I race Tamiya Mini 4WD cars.

I find the high speed movement and sound of each car careening around a circular track to be highly therapeutic, very much like a moving meditation. Each car is an intricate machine with many parts, the ultimate science experiment. Each track is like a puzzle waiting to be solved. You compete against others to see who can finish the race first, but your ultimate goal is to always try to build the best car that day. Young or old, male or female, anyone can enjoy this sport. Go fast. Don't crash! That's Mini 4WD.

TYPE-3 and ZERO Chasses

TYPE-3 and ZERO chassis cars (introduced in 1989 and 1990, respectively) have seen a resurgence of interest lately with the reissue of the Dash-1 Emperor, Super Emperor, Dash-0 Horizon, and Great Emperor kits and the three Classic Tune-Up Parts Sets. TYPE-3 chasses are upgrades over TYPE-1 and TYPE-2 chasses (introduced in 1986 and 1988, respectively) and improved on acceleration ability. There were also TYPE-4 and TYPE-5 chasses (introduced in 1990 and 1992). TYPE-4 still had mediocre features. TYPE-5 improved on cornering ability. Most modern Mini 4WD racers will likely never attempt to seriously race one of these cars believing that it is simply not possible to transform these cars into formidable racing machines, but I have seen a carefully designed ZERO chassis car win a podium spot in a tuned class race. In my own experiments, I've made a tuned class ZERO chassis car beat its box stock 10-lap time on a Japan Cup Oval Circuit by more than 10 seconds. Never discount the classics! Just be careful about racing these cars long term. Their weak chasses will likely be badly damaged after their first crash. Note the very simple design with lack of rear roller stay. You need to purchase the rear roller stay as a tune-up part.

Super TZ and TZ-X Chasses

Super TZ chassis cars (introduced in 1996) are very good at cornering but are mediocre in all other areas. These cars can be considered "your grandparent's Mini 4WD cars" because they came out over 25 years ago. There are many opinions about the raceworthiness of Super TZ and TZ-X cars, but they're all just opinions. If you know how to design your TZ or TZ-X, you will find yourself with a very formidable racer. It might not last very long after you crash it up a few times, but it can give the newer chassis cars a run for their money if you take advantage of its feather lightness.

I first encountered Tamiya Mini 4WD race cars in 1997 when I bought my first two kits from an Asian bazaar in Seattle: a Thunder Boomerang W10 and a Black Stalker (both Super TZ chasses). Although these were marketed as 1/32 scale cars, I read that they were actually 1/30 scale. I built the Thunder Boomerang, installed a Hyper Dash motor in it, played with it a few times, noticed how fast it was, and then stored it in its box until 2021, almost 24 years later. The batteries were still in the car. Not surprisingly, it didn't turn on. I changed the batteries, the car moved a couple of feet and then stopped. What was going on? I changed the motor and it did the same thing, moving a couple of feet and then stopping. Picking up the car, the wheels spun fast and made a high-pitched sound. It sounded normal to me, but I didn't have much to compare.

Little did I know, the little cog-like part at the end of the motor axle - the pinion - was the problem. Notice the crack in the gear that shows up when I enlarge the photo? The actual size of the pinion is less than 5mm. The motor was spinning, but the pinion didn't turn much because it wasn't gripping the axle!

Replacing the pinion was easy and inexpensive. I bought a pack of carbon reinforced 8T pinion gears. The car now runs fine, although a bit slow, even with a Hyper-Dash motor. There's nothing wrong with the motor because I installed it in an Aero Avante and there are no issues with speed. My Thunder Boomerang wasn't very sturdy as parts would fly off upon impact. I learned that I could replace the chassis with a new version of it, the Super TZ-X. Many Mini 4WD racers love this classic design and seek out these antique cars. Unfortunately, it's not very easy to upgrade these classic chasses as the body or parts may need to be cut or modified to work with current parts. My practice run with it yielded unfortunate results. The car blew up on the track. Instead of retiring it a life on a bookshelf, I upgraded everything on it and now it is one of the most raceworthy cars in my collection.

Some of the things you learn racing Mini 4WD cars parallels what you learn in life. When you drive real cars, you know that the fastest car doesn't always win races. Oftentimes, the car that wins is not the fastest, but one that can stay grounded around corners. The first two iterations of my Thunder Boomerang were the basic box stock build followed by a conservative set of add-ons for tuned class.

I added 17mm rollers with rubber rings and purple stabilizers up front and 19mm rollers with plastic rings and ball-race rollers in the rear. Adjustable mass damper weights were also added, two up front and four in the rear. I changed the gear from 4:1 to 3.7:1 and swapped the gear shaft for a fluorine coated gear shaft. The car is capable of handling a Light Dash motor, but a well-tuned Atomic Tuned motor can be faster than a Light Dash motor. Anything more would be too powerful for its specs. Aluminum wheels added some needed weigh to the rear of the vehicle. I crafted a new piece of tech - The "Dragon Tail" - and installed it in the rear of the car. The end result is Thor.

Super X and XX Chasses

Super X chassis cars (introduced in 1997) are classic racers your grandparents had. Every feature is pretty good, but its one potentially unforgiveable weakness is its cornering ability. This was the first chassis to use 72mm wheel shafts. The wide stance of the car means great stability, but that comes at the expense of cornering abiity. Think about how great a BMW or MINI is at cornering versus a typical wide American car. The ability to corner well is one of the keys to success in most Mini 4WD races.

Super XX chassis cars (introduced in 2009) is the successor to the Super X and provides a stronger nose guard to cover the bumper up front, stronger body and side guards, and additional mounting points on the side guards. Its greatest strength is the abiity to swap out motors quickly. It's a heavy but stable chassis because of the additional armor. Like the Super X, every feature is pretty good, except its cornering ability.

The Phantom Blade Black Special stays on any track like it's on rails, but it's not going to be winning any races soon because it's slow as molasses right out of the box compared to other box stock cars. Still, it's an intriguing design worth checking out and a little more competitive as a tuned class car.

Super II Chassis

Super II chassis cars (introduced in 2010) are beasts in cornering and acceleration, but have weak chasses and are known to be less stable than other chasses. If you are building a Super II car, replace any standard chassis with a polycarbonate ABS one. Add an EX Side Stay so you can mount side mass dampers. Sandwich the front bumper with a front roller stay and underguard plate to strengthen it. With a little ingenuity, you can have a front roller angle greater than 5 degrees. Replace the flimsy rear roller stay with carbon or FRP plates for strength, stability, and a myriad of expansion options. Copy the NEO-VQS Advanced Pack rear sandwich and you will have an excellent back end, but do use 19mm aluminum rollers for best performance. A well-tun ed Super II chassis car might be your next tuned class winning car. Lots of interesting animal racers are either VS or Super II chassis cars. Racing an animal racer is the easiest way to make your opponents lower their guard. Little do they know what's in store for them!

With a carbon plate up front and a triple-plate FRP sandwich on the rear (all three rear FRP plates from the NEO-VQS Advanced Pack), this tuned-class Super II racer gets its performance from parts made for the VZ chassis. The front plates have an >5 degree angle for downthrust. Solid aluminum rollers add weight and stability as Super II chasses are notoriously light and can course out easily. The 3.7:1 gear ratio and 24mm tires and wheels ensure good top speed and cornering speed. Front and rear underguard brakes enable this racer to negotiate inclines and lane changers safely. v2 has roller bearings, side mass dampers, and additional rear weight for better shock absorption.

The Shining Scorpion Premium and Kumamon Racer are speedy cars with the Shining Scorpion winning out due to its light weight (minus the side stay) and faster gear. Trust the Black Bear in highly technical courses.

The Neo Tri-Dagger ZMC Carbon Special has carbon everything, but it's a little disappointing in real-world speed tests.

The Astro Boomerang is a lightweight car that has a tendency to flip over easily, so transforming it to a tuned class car and weighing it down will correct its center of gravity.

AR Chassis

AR chassis cars (introduced in 2012) are great all-around racers and some of the sleekest-looking cars have appeared in AR chassis form. Only the MA chassis cars have better overall performance, but the AR is a tough chassis to beat. For box stock technical tracks, the AR is hard to beat. An included POM skid bar attachment acts as an underguard for the rear of the vehicle, helping it negotiate slopes better. AR chassis strength is pretty good and I would generally recommend an AR chassis to novice racers seeking durable, but fast and agile single-shaft motor cars. The AR Speed Spec Kit featuring the Aero Avante is an excellent first or second purchase. Some say that you can swap body shells between TZ or TZ-X chassis cars and AR chassis cars, but this is not always the case. The greatest strength and weakness of this chassis is the one-piece design, which requires cutting to reduce weight, but it can be argued that the chassis is already very well-designed, so why mess with something that's already good?

The Aero Avante is a cool-looking car that looks faster than it actually is. Its body is literally covered with stickers. It was especially challenging to line up all the stickers as many of them are adjacent to one another. I upgraded my Avante with the AR Basic Tune-Up Parts Set (green parts above). I also built an AR Speed Spec version of the Aero Avante (blue parts above). I used the AR Speed Spec version in the Tuned Class races on June 12, 2021. It's not that fast, but it stayed on the track.

The Flame Astute Red Metallic is not the be-all end-all box stock racer, but it sure is fast. Initial tests clocked in at 27 km/hr, but with the motor properly broken in after several races, it now tips the scales at 28 km/hr. Many of my tuned class cars are not as fast as this.

MA and MS Chasses

MA chassis cars (introduced in 2013) are great all-around racers. For box stock technical tracks, the MA is hard to beat. An included POM skid bar attachment acts as an underguard for the rear of the vehicle, helping it negotiate slopes better. MA chassis strength is pretty good, although your mileage may vary as I've had a polycarbonate chassis crack on me. The use of six rollers right out of the box makes this chassis a cornering monster and one of the most stable and raceworthy among all the chasses. I feel that MA cars are the best bang for the buck for novice racers, but just like other Mini 4WD cars, they must be built with great care and consideration to produce their optimum potential. The greatest strength and weakness of this chassis is the one-piece design, which requires cutting to reduce weight, but it can be argued that the chassis is already very well-designed, so why mess with something that's already good? The motor cover is relatively easy to attach and remove once you get used to it. A handful of people have attempted to make suspension systems for this chassis, but with no notable success.

MS chassis cars (introduced in 2005) are very good all-around cars, with MA cars typically being better right out of the box and because MA chassis technology is eight years newer, but MS chassis cars have a strong, stable following in the Mini 4WD community. Because the MS chassis has been around for so long, there are a lot of parts for it and there is a lot of experience modifying and optimizing the chassis by incorporating a suspension system into the removable front and rear units. Although there are attachments for a side mass damper plate, most people designing an open class car will opt for a body damper and use the attachment points for their suspension system. In the open class realm, the MS chassis is king of all monsters. Typically, MS chassis cars can be seen at the podium at every open class race and it is not uncommon to see all three spots won by MS chassis cars. Perhaps the only cars that have any chance of coming close to the performance of MS suspension cars are well-built VZ chassis cars, but VZ cars often lose time after a jump.

Both the MA and MS chasses are on the heavier side, so you will need to factor this in when designing your next MA or MS car. Both use double-shaft Pro motors that contain additional torque over single-shaft motors. Personally, I feel MS chassis cars are terrible box stock racers, but very good open class racers.

The Festa Jaune (MA chassis) is a hot-looking yellow sportscar. It's one of my box-stock cars. I did a motor break-in to try to coax a little more speed from the stock motor. As a result, my Festa Jaune is faster than my son's Festa Jaune Black Special and he actually has better tires!

The Exflowly (MS chassis) is another hot-looking car with a clear polycarbonate shell and a doube-shaft motor. You can see all of the innards of the car through its unpainted body. It's a terrible box stock car as it always flies off the track. It sure looks great on a bookshelf, though.

Slingshot is a best-in-class Shooting Proud Star Clear Blue Special (MA chassis). It's rock solid and fast due to its larger wheels and tires.

My open class Thunder Shot was built completely from scratch using an MS Pro flex suspension chassis. The body shell is polycarbonate. I fashioned my own back-to-front lantern body damper using car catcher material. The rear AT bumper is my Flexi-Plate design. It has a 3.7:1 gear, HyperDash motor, carbon wheels, and custom sponge low-frix and superhard tires.

Finally, my son's HyperSupreme tuned class car is based on his favorite chassis, MA. Although heavy, it's still a very fast car and rock solid due to the sliding damper up front.

FM-A Chassis

FM-A chassis cars (introduced in 2017) are a favorite among Mini 4WD racers who prefer having the heavier motor weight up front to better negotiate jumps. An included POM skid bar attachment acts as an underguard for the front or rear of the vehicle, helping it negotiate slopes better. Wide-height rear rollers are also a nice upgrade to the typical crappy box stock rollers. Some racers switch them to the front depending on the track. FM-A cars are acceleration monsters, so take care when selecting gears. FM-A chassis strength is pretty good, although your mileage may vary as I've had a chassis crack on me. For this reason, I would say chassis strength depends largely on the kit you buy. The Mach Frame has a very light, slender body with very litle protection for the chassis whereas a Copperfang has ample full-coverage protection for the chassis. Typically, I would see Mach Frames at the podium in every box stock race.


Medusa K4 has my standard single roller front/double-roller rear setup with mushroom car front heads and tapered ball-race rollers on the bottom rear. MadTang custom wheels with a combination low friction/super hard tires allow for less bounce on jumps and better cornering. Version 1 uses Tamiya tape to hold the cab together. I may rethink this for version 2. The Geo Glider Black Special is one of the fastest cars in box stock due to its carbon six-spoke wheels and low-frix arched tires. Unfortunately, the polycarbonate-reinforced chassis is its greatest asset and Achilles heel. I switched the chassis to a fluorescent one rendering it unusable for box stock.

The Tumbler resembles the Bale-era Batmobile with its rugged armor and take-no-prisoners panache. Next to the Avante cars, this car has the best sticker set around. Don’t be fooled by its modest 4.2:1 gear ratio. Its large wheels more than make up for that and, on the right track and with the right motor, it will compete favorably with the 3.5:1 cars.


You can't say enough about the Mach Frame. It's everybody's favorite box stock car. In one box stock race, nine out of 45 cars were Mach Frames. That should tell you how reliable and consistent the car is across tracks. The Mach Frame Black Special takes everything up a notch with the use of a polycarbonate-reinforced chassis, but I personally feel it is a piece of crap because the front roller mount can easily crack. The stiffer chassis ekes out another km/hr, but at the cost of being more fragile, even though the reinforced chassis is supposedly stronger. Weighed down in BMAX class, the Mach Frame is a monster. Don't push it too fast, though, as the car has a tendency to course out with motors above HyperDash.

VS and VZ Chasses

VS chassis cars (introduced in 1999) is perhaps the most adored and also the most hated of all the chasses. Just like TZ and TZ-X chassis cars, the technology in these chasses is antiquated, but there is a wealth of knowledge available for upgrading it. VS chassis cars make terrible box stock racers, which is ironic considering that their major market nowadays is children purchasing their first Mini 4WD car, which is typically a VS chassis animal racer. Its primary advantage is feather lightness, so take advantage of this in your design builds. You can win many races if your car is lighter and faster than everyone else's. VS chassis cars are renowned for their cornering and acceleration. Swap in a 3.5:1 gear in an animal racer and you have one formidable machine that will make you smile every time you beat a $600 podium car. Alas, the Achilles' heels of the VS chassis are its weak chassis and stability. Stay away from box stock races with this car. Turn these cars into tuned or open class monsters. Here's a tip: the downthrust angle of a VS chassis is 6.5 degrees versus everyone else's 5 degrees. Use that to your advantage.

VZ chassis cars (introduced in 2019) are successors to VS chassis cars and are improvements in every area except for the weakness of the chassis. There are several reports of broken front bumper stays, but these are easily replaceable. Both the front and rear bumper stays are removable so you can have a bumperless setup without the need for cutting or other such destructive modifications. The use of six rollers right out of the box makes this chassis a cornering monster. It is also hella fast on straightaways and curves. The VZ chassis is lighter than the VS chassis, so use that critical information when designing your next podium car. Every VZ chassis comes with POM plastic bearings and an 8T carbon pinion gear, but lacks a skid bar. Like the VS chassis cars, skip the box stock races and go for tuned or open class races. Add front and rear brake stays mounted with sponge brakes to your car to give it the ability to negotiate slopes.

Although the VS chassis is an antiquated design, many racers feel this is an excellent chassis for competition as it has a narrow wheelbase for tight cornering.

Many animal racers were introduced with VS chasses. Unfortunately, as box stock racers, these animal racers leave a lot to be desired. Use them as a basis for your tuned or open class cars.

The VZ chassis (Neon Vicky, left) has several improvements over its older sibling, the VS chassis. The VS chassis (Firefly, right) can still race with the best of them.

You can do no wrong with a VZ chassis. I built a VZ car made of all junk parts and it ended up being my fastest car at an unheard of 47 km/hr. The Dual Ridge is a very fast car that allows for quick modifications to its weight. Remove the tailfin and front faux springs to make it lighter and more solid. Reverse the front and rear rollers and you now have a battering ram up front.

I transformed a Toyota GR Yaris into a MINI Cooper. It is slow and heavy, but the ironic thing is, on the right track, all you need to do is replace the motor and you will find a competitive car for tuned or even open class without any additional hardware.

The NEO-VQS (VZ chassis), in its Advanced Pack form, looks very pretty, but one of the things that bugged me was their choice of rollers, which are crappy 12mm plastic rollers. This "tuned" car was about as fast as my Festa Jaune. The VZ chassis is basically the next generation VS chassis with strong, removable front and rear bumpers.

I upgraded the rollers to 12-13mm rollers on front and dual 19mm rollers on back. It took me several hours of work to align them properly and get them to spin freely. I also added washers between the wheels and body to make the alignment more stable.

I upgraded the standard axles with hollow shafts to lower the weight. I also swapped the NEO-VQS wheels and tires with those in the Exflowly kit because I liked the chrome wheels. This new configuration now appears to be twice as fast as my Festa Jaune. When they start at the same spot, the NEO-VQS quickly catches up to the Festa Jaune in a few laps.

I upgraded the low friction POM keylets - the plastic rings that the axels spin inside - with hex-hole ball bearings and bearing roller spacers for a smoother wheel rotation. I changed the gear to 3.5:1.

I replaced the Light Dash (LD) motor with a Torque Tuned Motor (TT). TT is a monster motor after break-in.

On deck for the next upgrade is replacing the standard engine gear shaft with a fluorine coated gear shaft for improved motor performance, changing the rollers to 12-13mm with rubber rings.

The NEO-VQS Advanced Pack has hidden things to discover that become more apparent as you experiment with the car. Removing the yellow front bumper and sandwiching the black guard with both FRP plates reduces the weight by 5 grams and reduces the initial lap time significantly. I also chose the roundest of the wheels in the NEO-VQS and placed them in front and the roundest of the Exflowly and place them in the rear. Average lap times decrease from 1.4x-1.5x to 1.3x. Replacing the Energizer alkalines (46.73g each) for Energizer 1300mAh rechargeables (43.1g) results in a lighter car.

Even something so simple as a back latch (1.01g on an Aero Avante versus .53g on a NEO-VQS versus .42g on a Thunder Boomerang) makes a difference in weight and speed.

This car looks much better with the chrome-plated wheels from the Exflowly.

The Dual Ridge is already pretty fast on its own, but with the lighter polycarbonate body of the Japan Cup 2021 version, this car wil fly around the track. Swap the front and rear rollers and you will have a very formidable vehicle that will cause plenty of vibrations behind it.

Mini 4WD Race Journal

HobbyTown Tom's River Mini 4WD Open Class Race - May 8, 2021 - I entered Neon Vicky in my very first Open Class race. It had trouble staying on the track on its second 90 degree angle turn. Neon Vicky was faster than every other car in the field, but it flew off the track on that right angle turn. The racemaster looked at my car and said I should pitch the wheels inward. He also said I could add more weight to the front of my car. Changing the batteries from NiMH to alkalines helped keep the car down somewhat, but it still flew off the track. I changed the front plate to carbon and replaced the 12-13mm aluminum rollers with 19mm aluminum rollers with plastic rings. I added two weights up front with a shorter shaft to keep the weight towards the ground. I reattached the rear underguard, realizing that it was needed to keep the screws from catching against the top edges of the track. A drop test revealed a good balance. I replaced Neon Vicky's switch terminal cover with an NVAP switch terminal cover for better strength, since the NVJC one kept lifting up after impact. Under the body shell, I changed the blue sponge pad on the passenger side to pink to match the driver side sponge pad. I shaved the two humps at the front of the carbon plate to keep the car within spec. I moved shortened the body damper in order to move the side weights closer to the front wheels like the NVAP. I also added lightweight weights to the front of the car for better balance. It should be able to handle jumps better with the body damper and additional weight. I added MadTang custom wheels with a combination low friction/super hard tires mounted on carbon Y-spoke wheels and 72mm hollow propeller shafts for better cornering. I attached two mushroom ball heads on the front roller shafts to deal with cornering. I attached a ball head under the main screw of the canopy so there won't be any accidental sticking after a jump. Surprisingly, the cars weighs the same as before.

Neon Vicky, May 2021

HobbyTown Tom's River Mini 4WD Drag Racing - May 8, 2021 - Pengo - Drag Racing is a new class in Hobbytown Tom's River. I initially just wanted to be a spectator, but I ended up competing in it and won. We were allowed to use tuned class racers. My entry was a fully optimized box stock Penguin Racer. My Fujitsu batteries were charged at close to 100%. I recharged my batteries after every heat.

Tuned class motors (RT, AT, TT) are not the most powerful motors. You could go with RT, a speed demon with low torque, or TT, a torque monster with low speed, or AT, a balanced lower-powered combination of both that is just one step above BX, a basic box stock motor. My racer had huge wheels, which are traditionally used for speed cars. I felt that TT was the best choice for my car. In fact, I think the TT is probably the most powerful motor of the three. It really packs a punch so long as you keep your car's weight real low. Just before my first drag race, I made some quick decisions on reducing my car's weight:

  • Swapped the battery clip (2.1g with penguin) with a standard VZ chassis battery clip (.58g with no penguin) to reduce the load by 1.52g.
  • Swapped the VZ back latch (.53g on a NEO-VQS versus .42g on a Thunder Boomerang) to reduce the load by .11g. The Thunder Boomerang back latch is one of the lightest I've come across. It is .01g lighter than the animal VS chassis racers.
  • Changed the gear from 5:1 to 3.7:1.
  • The overall weight of my Penguin racer was 80g without and 115g with batteries.

With a TT motor, 5:1 gears yield 19 Km/h whereas 3.7:1 gears yield 29 Km/h.

Several people wanted to buy the Penguin racer after they saw me win. In the final race, I won by a roller length, so there's room for improvement. I improved Pengo with the following upgrades:

  • Changed the gear from 3.7:1 to to 3.5:1.
  • Changed the gear to include ball bearing and fluorine coated gear shaft.
  • Remove the spoiler to reduce the load by 1.7g.
  • Swap the Thunder Boomerang back latch with a rubber body catch (part 95393) to reduce the load by .35g (.42g versus .08g)
  • Pengo now weighs 78g.

With a TT motor, 3.5:1 gear, and pink Fujitsus charged to 1.51V, the car can go 31 Km/h. Adding a bearing spacer to my gear actually reduces speed, so I omitted it.

HobbyTown Tom's River Mini 4WD Tuned Class Race - June 12, 2021 - As weird as it sounds, I think Tuned Class is more difficult to win than Open Class. Maybe it's because there is greater competition and less ego involved. Everyone has to build their cars within spec without cutting or shaping parts and every car is limited to one of three low-powered motors: TT, RT, or AT. Most cars seem to use AT motors. I was surprised to see many cars with plastic rollers. Neo Victor kept flying off the track so I had to switch to heavier batteries and wait for a lower charge. I also switched its TT motor to an AT motor and changed the gear to 3.7:1. I raced the Blue Beetle and came in second in every race. Other cars were flying off the track and getting disqualified. In the races for the finals, I switched to Neo Victor so I could be competitive against the faster racers, but wasn't successful as my car was still flying off the track even with the lower battery voltage.

I purchased two copies of the NEO-VQS Japan Cup 2020, one for collecting and one for racing. I purchased an additional NEO-VQS Advanced Pack for spare parts and at least $100 worth of additional spare parts with the goal of creating a competitive racing car. In the following analysis, NEO-VQS Advanced Pack parts will be referred to as NVAP and NEO-VQS Japan Cup 2020 parts will be referred to as NVJC. Other parts not in either set will be identified by Tamiya part number.

  • The NVJC opaque yellow plastic molded parts are lighter than the NVAP translucent yellow plastic molded parts. I did not replace any chassis parts with NVAP parts.
  • The NVJC wheels are carbon reinforced wheels (Y-spoke). These should be stronger than standard wheels. They also add an understated beauty to the car.
  • Like my NVAP car, I removed the A4 front bumper for a savings of 2.12g and a faster burst of acceleration in the first lap.
  • I removed one of the FRP rear plates for a savings of 1.93g. I double-stacked one set of the brakes to make up for the lost plate.
  • I shaved off the sides of the chassis for negligible weight savings, but it looks cooler and more streamlined.
  • I replaced the 60mm hex shafts with 60mm hollow stainless steel shafts (part number 15440). According to Tamiya, "this shaft weighs 2/3 of the normal shaft and has the same strength." I cleaned the hollow shafts with rubbing alcohol to remove metal dust. This improves the overall efficiency of the shafts so the wheels can rotate faster.
  • I replaced the POM keylets with hex hole ball bearings (part number 15287) and bearing roller spacers (part number 94768) between the chassis and the wheel. I cleaned the ball bearings with lighter fluid for 4 hours, shaking the solution every hour, to remove oil residue. I cleaned the ball bearings with rubbing alcohol to remove lighter fluid residue. The POM keylets do a very good job as stock keylets, but the ball bearings reduce the lap times by .03 seconds. I discovered I did not need washers in between the spacers and wheels. The act of removing and inserting the wheels on the shafts multiple times decreased the gap between the wheels and the chassis.
  • I replaced the front rollers with 12-13mm double aluminum rollers (part number 95581).
  • I replaced the rear rollers with 19mm alumonum ball-race rollers (part number 95582).
  • I replaced stock propeller shaft (beige pinions) with NVAP hollow propeller shaft (green pinions). I cleaned the hollow shafts with rubbing alcohol to remove metal dust and saved .36g.
  • I kept the 3.5:1 gears from NVJC. These gears are faster than the 3.7:1 gears frin NVAP.
  • I replaced the switch terminal cover with the NVAP one for better durability. The NVJC switch terminal cover kept popping off on impact after course outs. This led to a weight gain of .04g.
  • I chose the 950mAh Fujitsu batteries that weigh 36g over the 1300mAh Energizer batteries that weigh 43g for a savings of 7g.
  • The overall weight of my NVJC is 105g, a savings of 10g over my NVAP.

HobbyTown Tom's River Mini 4WD Drag Racing - June 12, 2021 - Pengo v2 - I entered the drag race at Hobbytown again and won easily. My car has become something of a curiosity for other racers who are used to racing circuits. One racer asked to see my motor because he couldn't believe my car could be so fast with a tuned motor. I think he expected to see a more powerful motor in my car so he could prove I cheated, but he was surprised to see a TT motor in my car. Most people who probably pick an RT motor because RT emphasizes top speed, but, from my tests, a TT motor is faster than an RT motor. Plus, it seems that a car with a TT motor appears to go faster and faster the longer it's on a straightaway. "Don't change a thing on that car," the racemaster said, "because, right now, that's the car to beat." Of course, I tuned it again, because that's what I do.

I updated Pengo with an Avante polycarbonate body and a rubber body catch. Pengo now weighs 108g with batteries and 72g without. It should have been a little faster now with the lighter body, but the Tamiya speed checker says that both versions have the same top speed. The speed checker never tells the whole story, though. I lost in the July drag race finals. The other racer had a car with an Atomic Tuned motor. That was an eye-opening experience to see his Atomic Tuned car beat my Torque Tuned car on a straightaway.

HobbyTown Tom's River Mini 4WD Open Class Race - June 12, 2021 - I entered Neon Vicky in my second Open Class race. MadTang's custom wheels/tires helped my car stayed on the track better than with my regular wheels/tires. i didn’t win anything in the race, but i feel my car is a few tweaks away from succeeding. The amazing thing is the car is so fast even without a ball bearing and fluorine coated gear shaft in its gear! I wonder how my car would fair with a slower motor and 3.7:1 gear.

I reinforced the switch terminal cover with small pieces of sponge to prevent it from popping out upon impact.

Neon Vicky, June 2021

HobbyTown Tom's River Mini 4WD Open Class Race - July 10, 2021 - I entered Neon Vicky in my third Open Class race and won a bronze place for my win at Hobbytown Tom’s River! My prize was a new motor for my son’s car. For this race, I replaced the Sprint Dash motor with a Hyper Dash motor and added wheel stabilizers in place of the mushroom caps.

Neon Vicky, July 2021

July 14, 2021 - I removed one set of rear rollers on Pengo and replaced the steel wheel shafts with hollow shafts.

Penguin racer, 3.5:1 gears (blue/yellow), fluorine coated gear shaft with 520 ball bearing (no spacer), carbon reinforced crown gears, standard propeller shaft (mustard), blue POM 620s, 60mm hollow stainless steel wheel shafts, TT motor, Avante poly shell, rubber body catch, one set of rollers front and rear.

HobbyTown Tom's River Mini 4WD Tuned Class Race - September 11, 2021 - I entered Thor in the Tuned Class race and won a silver place for my win at Hobbytown Tom’s River! Because I wanted this car to run in Tuned Class, I installed an Atomic Tuned motor in it. I found the purple stabilizers to be pretty useless for the Hobbytown tracks, so I replaced them with 16mm plastic rollers. I may have to rethink this as one of my plastic rollers and one of my tapered ball-race rollers got pretty wrecked on the track. I moved the rear mass damper weights towards the middle for better stabilization. Everyone raced beautiful cars. Mine was held together with a lot of tape as it endured many crashes in practice. I replaced and repaired parts after each run. I lovingly call it my Frankenstein car. After the race, I replaced the bad plastic roller with a good one and replaced the wheels with aluminum ones to get the center of gravity lower. These wheels are supposed to be specially designed for STZX chasses. I reduced the mass damper weights in the rear. I also replaced the crappy battery latch with a better one of my own design, a modified VZ chassis battery latch.

HobbyTown Tom's River Mini 4WD Box Stock and Open Class Races - November 13, 2021 - I won bronze in Box Stock with Voltron. In Open Class, against a $600 "podium car" and the racemaster's car, Neon Vicky did fairly well in the final race and won silver, but the heats that led up to it were absymal. The wheel stabilizers slowed my car down to a crawl even with a Sprint Dash motor installed. I decided to go back to basics, removing the wheel stabilizers and using Rayovacs to weigh the car down. Those simple changes enabled my car to be highly competitive, negotiating turns without the slowdowns the wheel stabilizers gave me. One of my long screws is slightly bent. Had I used the stronger, more expensive carbon reinforced screws, I would've faired better. This month's track roughed up the rollers on all my cars.

Neon Vicky, November 2021

December 19, 2021 - Thor's aluminum wheels now have a 60mm reinforced shaft between them. These rear rollers are now higher and held with carbon reinforced posts.

Neon Vicky, January 2022

HobbyTown Tom's River Mini 4WD Open Class Race - February 13, 2022 - I entered Thunder Shot in this month's Open Class finals race and won a silver place for my efforts. It was my first MS suspension car and faired pretty well against a much more powerful MS suspension car, so I was pretty happy with my results.

Thunder Shot, February 2022

HobbyTown Tom's River Mini 4WD Open Class Race - March 12, 2022 - I entered Wolfie, a VS chassis car, in this month's Open Class finals race and won a silver place for my efforts. It competed well against a suspension car, so I was pretty happy with my results. I made a number of modifications to the previous version, including front stabilizers, a carbon front plate, new front mass dampers, new front underguards made of carbon pieces, new rear aluminum tapered ball-race rollers, new location for the rear mass dampers, a new rear underguard, and new tire/wheel set with low-friction/sponge front tires and super hard/sponge rear tires. The body damper is my own design made with body catcher material. This month's racetrack had an incline curve, two dragonbacks, and four digital curves, so I needed to slowed down my speed cars. I replaced my Power Dash motor in Wolfie with an Atomic Tuned motor, which was still pretty speedy. I was going to race Neon Vicky with a Light Dash motor, but it just wasn't as stable as Wolfie.

Wolfie, March 2022

AAA Hobbies Mini 4WD Box Stock Race - June 5, 2022 - I entered Voltron in this month's Box Stock finals race and won silver place! I removed the brake and battery cover from my car to reduce the weight down to 80g. I also swapped the front and rear rollers for better grip on turns. I won the first qualifying position, ahead of everyone else. In the final race, the car that beat me won by a hair. I didn't have the best release on the drop, but gained on the lead car and even surpassed it in the middle of the final lap, but the other car eked out a victory in the end. My son entered his new Shadow Shark Italia and was supposed to be the second qualifying position, but was beaten by a slightly faster car. He got to the third semi-final, but couldn't win in the end. I won a number of prizes, including a Mini 4WD car kit, an oil pen, Tamiya tape, and a gift certificate. I also entered Kogo in Tuned Class and won a number of heats, but coursed out in all three semi-final races on the last lap. The sad thing is Kogo was faster than every other car there. In all instances that Kogo started from behind other cars, it was able to eventually overtake them. It was just a case of bad luck. My son entered my car, Thor, and he did quite well, but also lost in the third semi-final race in the end.

HobbyTown Tom's River Mini 4WD Races - June 11, 2022 - No victories in any of the races. My cars coursed out in the semi-finals or finals. Especially disheartening was the Open Class finals race where my car made its jump properly on the first turn of the first lap and a car next to me coursed out and hit my car, sending it flying off the track. There's something to be said about releasing your car after everyone else releases theirs.

AAA Hobbies Mini 4WD Races - July 3, 2022 - No victories in any of the races. Voltron wasn't as proficient on this slower, more technical track that had a loop, a jump, and inclined curves. My son's Shadowshark fared a little better. Sadly, my son's car didn't get into the finals, because I dropped his car late while posing for a picture opportunity. Pango wasn't the fastest car, but was pretty competitive and fared better than my son's Midnight. Voltron and Pango both coursed out in the semi-finals. I had faster cars I could've raced, but they wouldn't stay on the track. I'm not concerned about my recent losses because I took a very conservative approach to car configuration.

HobbyTown Tom's River Mini 4WD Open Class Race - July 9, 2022 - I won silver place in the Open Class finals race with the newest member of my fleet, the Firefly VS chassis.

Firefly, June 2022

AAA Hobbies Mini 4WD Box Stock Race - August 7, 2022 - I won bronze place with Phoenix in this month's Box Stock finals race. I would've won gold, but my car flew off the track on its final lap. My prizes were a JR case for Mini 4WD car box and a red plastic spacer set. I entered Kogo in the tuned class race and, racing for the final spot of the race, my car was well ahead of my competitor, but it flew out on the curve just before the finish line. I removed the rear block weight on Kogo, which made it super fast, perhaps too fast for its own good.

HobbyTown Tom's River Mini 4WD Open Class Race - August 13, 2022 - I won gold place with Phoenix in the Box Stock finals and silver place with Firefly in the Open Class finals. Firefly's refinements include a white bell HyperDash, round carbon underguards, and black matte dampers. My prizes included the Roborace 2.0 and Eleglitter car kits. My son won gold place with his new DCR-02 car in the Kids Box Stock finals.

Dxn Provisions Mini 4WD Fast Fridays - August 26, 2022 - When I arrived at Dxn for Fast Fridays, the Tuned Class races had already started, so I didn’t have a chance to test my cars, however, they were able to fit me in as one of the final competitors. Little did I know, this was not a three strikes and you’re out affair. It was a one and done! Both of my cars flew off the track. My Open Class cars fared a little better, but were too slow compared to my competition. I had to figure out what to do to reduce their weight and make them run faster.

Dxn Provisions Mini 4WD Summer Cup Round 3 - August 27, 2022 - Saturday's races were part of the Summer Cup series, a five-week contest where the person with the highest scores wins the Summer Cup title. Everyone fervently worked on their cars. Some brought multiple pitboxes of varying colors and raced multiple cars, no doubt a testament to their love for and longtime experience in Mini 4WD racing. It was cool that many of the people there already knew of my reputation as a YouTuber. One guy recognized me and showed me his version of the rear-to-front roller VZ car he made. He learned how to make one through one of my videos. He mentioned a technique he discovered to dampen the new rear roller by untightening the screws. Even the Minnesota man who travelled here every other week for the cup races knew who I was. They seemed impressed that I flew all the way to the West Coast just to race my cars. My best race was Box Stock. I was supposed to win my heat, but my car slowed down in the final lap. My Tuned Class and Open Class cars fared very well in practice against other racers, but coursed out in the actual races. Firefly was definitely competitive, but I was a bit overzealous tuning it for Open Class. I kept looking at it again and again before my race. I just wanted to win one heat while I was here. I decided to amp my motor and lube my rollers, so I borrowed a friend’s Voodoo oil for my motor and Dxn oil for my rollers. Powering it on, Firefly sounded like a new car, but now it was too fast for its own good. It was at peak speed and its batteries were not even at full strength! “Your car is too fast,” a colleague advised after reviewing the racing video. The moral of the story: When we get too greedy, we can die. It was remarkable to see so many passionate Mini 4WD racers. Many different nationalities of all ages were represented, both men and women. I was especially amazed at the skills of a young Asian female who had some formidable cars. Everyone was very encouraging and not ego-driven. When everyone saw someone doing well, they cheered him or her on. People seemed more interested in seeing the best car win rather than care who was racing. I feel happy and honored to have raced at the mecca of Mini 4WD racing on the West Coast.

HobbyTown Tom's River Mini 4WD Open Class Race - September 10, 2022 - I won bronze place with Firefly in the Open Class finals. I had to dumb down my car by using a Light Dash motor for this month's very technical track that caused many racers' cars to course out. My prizes were a tube of Tamiya bearing lubricant and a keychain. Firefly used 1.54V Rayovacs in the finals.

AAA Hobbies Mini 4WD Box Stock and Tuned Class Races - September 11, 2022 - I won gold place with Phoenix in this month's Box Stock finals race. My prizes were a Mini 4WD pro racer's box and a gift certificate. Phoenix was several lengths ahead of the others and I was lucky to make the lane changer every time except for one time in practice. I won gold place with Pango in this month's tuned class race. My prizes were a Tamiya shoulder bag and a gift certificate. Pango lost in the first round, so I changed the motor from Torque Tuned to Atomic Tuned and it became the car to beat in the second round in this month's speed track. Pango was only 26 to 27km/hr, so its top speed wasn't that fast, but the synergy of everything it was equipped with helped make it a much faster car than it was. Phoenix used 1.56V Rayovacs in the finals. Pango used 1.51V Neo Champs in the finals.

The Liberty Cup, Round 1 - September 18, 2022 - I won gold place with Voltron in this month's Box Stock finals race. My son Matthew won gold with The Midnight in Tuned Class. Co-host Evan and I designed a very technical track with two loops and three jumps that forced everyone to consider battery strength and car speed. We had 6 cars in Box Stock and 7 in Tuned Class with 6 racers in attendance and one proxy. We offered prizes that rivalled the hobby shop races.

AAA Hobbies Mini 4WD Awards Ceremony - October 2, 2022 - I won a bronze medal for the 2022 racing season (May to September) in the Box Stock category. There were 94 racers this season, so this was no small feat. After the ceremony, a good number of us stayed behind to race each other on the in-store track.

The Liberty Cup, Round 2 - October 16, 2022 - I won bronze place with Voltron in this month's Box Stock finals race. Unfortunately, my new Vulture Mach Frame did not get into the finals, but it still did very well considering it didn't have any damper weights and I built it the day before without cleaning the bearings. Co-host Evan was out sick, so it was a challenge setting designing and setting up the track by myself, but thankfully my friend Ken was there to assist with the track assembly and disassembly. I designed a very technical track that some say outdid last month's track. An elevated tabletop with four jumps, a loop, and hairpin turns made this a dynamic and devious challenge for every racer. We had 10 cars in Box Stock and 15 in Tuned Class with 10 racers in attendance and one proxy.

HobbyTown Tom's River Mini 4WD Open Class Race - November 12, 2022 - We were late on arrival and could only enter tuned class and open class. No victories in any of the races. My cars coursed out in the semi-finals or finals.

The Liberty Cup, Round 3 - November 20, 2022 - I won gold place with Venom FM-A in this month's Box Stock finals race. I also won gold place with Green Goblin in this month's Tuned Class finals race. We originally laid out an ambitious track on the rooftop, but the 25mph winds destroyed it several times, so we had to move our event indoors. We raced on a smaller, but equally fun track. The major components were all there: my new rainbow lane changer, hairpin turns, a little tabletop, and washboards. I initially thought the washboards were useless, but they did affect some of the cars. Unfortunately, my Vulture Mach Frame suffered a head-on collision with another racer's car that flipped over and headed backwards towards me. Co-host Evan was out sick, so it was a challenge setting designing and setting up the track by myself, but thankfully my friend Ken and the racers were there to assist with the track assembly and disassembly. We had 11 cars in Box Stock and 11 in Tuned Class with 5 racers in attendance and one proxy.

Mini 4WD Engine Horsepower

You can measure net horsepower of your Mini 4WD motors by attaching it to a GE-Force Mini Break-In system set at 3.0V using AC adapter power and measuring your motor's RPM using the Giri app on your iPhone or Android. Some people may say that 3.0V is too much voltage, so any such results are artificially inflated, but if you test all of your motors the same way, you will be able to compare any motor to any other motor in this set. Giri outputs your motor's speed in RPM.

You can measure power at the wheels by placing your car's front tires on the bottom rollers of a Tamiya Mini 4WD Speed Checker. Some people may say that any such results using this method are artificially inflated, but if you test all of your cars the same way, you will be able to compare any car's speed to any other car's speed in this set. The Speed Checker outputs your car's speed in km/hr.

Your motor's RPM and car's km/hr speed is roughly 1,000 to 1, so a 27,000RPM motor should give you roughly 27km/hr in your car as measured on the Speed Checker. There should be very little parasitic drag from the motor to the wheels if your car parts are new(er) and you build your car properly. The actual speed of your car will depend on not just the motor and the wheels, but tire compound, rollers, dampers, weight, stability, drag, humidity, and track conditions. The latter is perhaps the most unpredictable element of all.

Reviving a Dead Motor

Hard impacts in rapid succession may affect the functionality of the motor inside a Mini 4WD car. The motor may slow down or come to a complete stop. Remove the motor from the car.

Attach the motor to a G-Force Break-In system at 1.5V via AC adapter. Do you see smoke coming out of the motor? Stop the process immediately. Detach the motor from the G-Force. Place the motor in the freezer for one hour. Remove the motor from the freezer and let it warm to room temperature.

Spray electronics cleaner into top and bottom openings of the motor (endbell and pinion side). Wrap motor in paper towel and shake to remove debris.

Water Bath

Attach the motor to a 3V battery pack and submerge the motor in a double shot glass full of water. Power on the battery pack and let it run for 1 minute, stop and rest for 1 minute, replace the water, power on the battery pack again for 1 minute, stop and rest for 1 minute, replace the water, add Ganapati liquid bearing oil to the openings of the motor, power on the battery pack again for 1 minute, stop and rest for 1 minute, replace the water, add Ganapati liquid bearing oil to the openings of the motor, power on the battery pack again for 2 minutes. Remove the motor from the water. Shake and tap the motor on a paper towel to dislodge liquid debris inside. It is normal for the water to get cloudy when the motor is submerged and running in the water.


Attach the motor to G-Force at 1.5V via AC adapter. If there's still smoke, your motor is probably toast. If not, stop the process and set G-Force to 3V via AC adapter.

Let G-Force run for 1 minute forward. Add drops of oil to the slots on the colored end bell. Blow at the endbell and use a little compressed air in the slot holes. Let G-Force run for 1 minute reverse. Repeat two more times. Check Giri for currrent speed versus known speed of this motor. Remove the leads and turn motor over 180 degrees, tap it against a paper towel to remove liquid debris. Wipe excess oil off motor. Rest for one hour.

Test Motor

Insert the motor into a junk chassis. Let it run for 2 minutes on a track and 2 minutes holding it in your hand on junk batteries (1.3 to 1.4V each). Check the speed. Rest for one hour. Repeat two more times.

Insert the motor into a car. Check Tamiya Mini 4WD Speed Checker. Let it run on a track.

The Sound

The sound of an optimized motor will be a high-pitched metallic ringing sound. It's a musical pitch rather than a generic motor sound, music to your ears. You'll know it when you hear it. For HyperDash motors, do not run a motor for more than 1 minute on a G-Force Break-In system at 3V via AC adapter. You will prematurely burn out the motor. Races are typically less than 1 minute duration.

Sometimes there is no way to revive a dead or burnt out motor. At best, a burnt out motor will end up being a box stock motor. At worst, it goes to motor heaven. At that point, open it up and remove the white motor spacer inside. Use the spacer for your open class cars. However, bear in mind that it takes a lot to kill one of these little motors. Try to revive it again or use it as a slow motor in a test car.

Mini 4WD Science

Weight: An average sportscar weighs around 3,000 pounds. Shrink that down to 1/32 to equal 93.75g, which is considered a very light Mini 4WD car. Most box stock cars are around this weight. I always try to target my Mini 4WD cars as close to that ideal weight as possible, but there are many instances where greater weight is needed to stay on a complex track with lots of hills, inclines, drops, curves, turns, and lane changers. Every gram is equal to about 32 pounds. A car battery typically weighs around 40 pounds, so think of every gram you can remove from your Mini 4WD vehicle as shaving off the weight of a car battery. A lighter car is a faster car, but you will need to take into account the nuances of the track you are racing on to see if you can keep it that light or make it heavier to remain on the track.

Height: The lower the height of the car, the more it will hug the ground. Taller cars have a tendency to roll over easily. A car can also be too low and flip over onto its back in tight turns.

Length: The longer the car, in relation to its width, the longer the car can glide after jumping off a hill.

Wheels: Most wheels are made of cheap PP plastic. ABS is stronger. Carbon reinforced wheels are the strongest and most recommended. If the wheels haven't been used a lot, 60mm shafts are fine. If the wheels have been used a lot, pierce the wheels and use 72mm carbon reinforced shafts. You can save more than a gram of weight by using a hollow propeller shaft and hollow shafts for your wheels, but they are not as sturdy as the carbon reinforced shafts.

Tires: The harder the tire, the higher the car will bounce up after it lands from a jump. Sponge tires absorb impact best, but will not allow your car to reach its potential top speed like hard tires. Soft, grippy tires are sometimes good on tracks that have many consecutive hairpin turns, but they are also notorious for sliding off wheels easily, so secure them with Tamiya tape between the tire and the wheel. Select tires based on the track you are racing on.

Motors: Tune and oil your motors for optimal results. A day before every race, run and test every motor you will use to ensure expected performance. Label each motor with its km/hr number.

Rollers: Small rollers up front with wide rear rollers for a combination of speed and grip around corners. Wide front and rear for technical tracks. Rubber O-ring rollers to slow a car down around corners. Plastic O-ring rollers for a good combination of grip and speed. Stabilizers above rollers to decrease the chance of course outs. Lubricate the ball bearings of all rollers for maximum speed. You don't always need maximum speed, so lubricate less when you don't need it.

Weights: Front, rear, and side weights comprise the mass damper trilogy. Some tuned class cars don't need side weights depending on the track. More weight equals slower car. Less weight equals greater chance of course outs on a sharp turn or jump. More front weight to dip the nose down and negotiate jumps better. More rear weight to reduce the jump distance. Distribute weight so car lands flat or bounces minimally. In box stock, something so minimal as a screw can be a weight, too.

Bodies: If you customized your car to run well without a body, then use a polycarbonate body to minimize the weight, otherwise your design must consider the weight of the body shell. The additional weight from all the interconnecting parts in or around the body must also be considered. There are times when you will use or omit a tail fin, canopy, or one or more pieces of a multi-piece body depending on the track.

Track Vibration: Running your car solo on a track only tells you half the story. Running your car alongside others forces you to consider track vibration.

Balance: Drop test your cars using a variety of methods: the front and rear drop test, the height drop test, and the angled drop test. Some tracks have more left turns than right turns so you can adjust your rollers and weights accordingly.

Brake: Using a lighter or mini flame torch, lightly melt the long edge of the brake that comes into contact with the track first. Before it cools, press the brake against an aluminum setting board to evenly flatten the edge of the brake.

Oil and Grease: Do not use the grease in the little blue toothpaste tube that comes with the kit. That is inferior to the F grease you can buy separately (picture on the right). Do not use either kind of grease on your wheel shafts. Use an oil pen or Ganapati oil instead.

Genericism: I have seen racers copy their favorite designs from others and the end result is these racers end up with a generic car. I would rather make my own mistakes and learn from them than copy someone else's designs.

Reproducible Elements: Just like any science experiment, the goal is to create reproducible results. There will always be random elements that will affect the outcome of a race, but there are things you can do to mitigate uncertainty. Observe and record the outcome of any changes you make to your cars. Study slow-motion videos of your cars as they traverse various obstacles. Learn what each specific part does and how it affects your car's performance.

On-the-Fly Tuning: Learning to tune your car after every heat is an art form and a mystery to many people, but once you develop these skills, you will be a very formidable racer. I have seen cars that course out in every heat until the last race when it counts. In that last race, the skilled tuner can tweak his or her car to give it a podium finish.

Note: These are only guidelines. Don't let these be rules that prevent you from having fun creating your own unique designs!

Geekgirl Clare's Mini 4WD Inventions

DragonTail - introduced June 2021 - a variable brake that handles different inclines better than a rectangular linear brake
Flexi-Plate - introduced June 2022 - an AT pivot bumper that pivots vertically rather than horizontally with independent left/right pivots
Roller-Guards - introduced July 2022 - underguard protection for cars that use standard rollers as bottom rollers

The Geekgirl Clare garage also has numerous design innovations with regard to underguards and body dampers.


The Venom-Tuned series are Mini 4WD box stock cars that have undergone all the latest break-in processes that I invented or learned. Like the AMG, M, or John Cooper Works series of Mercedes, BMW, and MINI cars, Venom-Tuned cars bring the excitement of street-legal racing to Mini 4WD box stock cars. Each car starts with a high-performance Venom-tuned engine that's over 33% faster than straight-out-of-the-box (SOOTB) box stock motors*. Stage 1 Venom Tuning begins with a 24k water-tuned engine with 1.99 spec wheel shafts, Ganapati-lubricated roller mounts and joints, optimally lubricated gears and pinions, optimally adjusted rollers, propeller shaft, tires, and wheels, and even optimal sticker placement. The goal is to achieve a fast, balanced car before I badge the Venom label on it. Stage 2 Venom Tuning contains all of Stage 1 plus an upgraded 26k Venom-tuned motor (44% faster than SOOTB motors). The Venom-tuned motor is an unmodified SOOTB motor that is broken in with various techniques that requires about 3 hours to complete. Stage 3 Venom Tuning contains all of Stage 1 plus a >=28k Venom-tuned motor (55% faster than SOOTB motors) cherrypicked from the very best Stage 2 motors. Microadjustments are made to joint and roller lubrication to accommodate the higher powered Stage 2 and 3 motors.

Phoenix is the first example of a Venom-tuned car prior to the incorporation of the Venom-tuned label. It was created as a prototype that uses all the techniques of Venom-tuning.

* SOOTB motors typically generate 18k RPM via GForce Motor Break-In @ 3V

Frequently Asked Questions

Which is harder: Box Stock, Tuned Class, or Open Class races?
Each class of race offers different challenges. Box Stock and Tuned Class force you to work within a system. Open Class allows you to unleash your creativity so that you can invent new parts and introduce new concepts. Your ability to fare well in a particular class depends a lot on your creativity, personality, experience, and budget. The beauty of Mini 4WD racing is anyone can race and anyone can win: young or old, male or female, novice or pro. Never underestimate anyone and always race humble.

Which is harder: 3-lane or 5-lane races?
It really depends on the track design. The Japan Cup focuses on 5-lane races, but most of the serious racers who come out of the Phillipines and Japan race on 3-lane tracks. Both offer different challenges, but the 3-lane tracks often have tighter turns and flex more easily due to their narrower width. The lane changer on 3-lane tracks is much more difficult to traverse than the rainbow lane changer on 5 lane tracks. 5-lane tracks may have angled or even near-vertical inclines that may pose challenges to some cars. The most challenging tracks combine both 3-lane and 5-lane racing.

How do you keep a car's weight down?
Pare down a car to its barest essentials. Apply spray paint instead of stickers. Find and use the lightest components that support your design. Design your car around what batteries you will use. If you use NiMH batteries, your car may need to be heavier or you may need to cut the chassis to drop the batteries lower. A popular YouTuber described his Open Class cars as being 120 grams. I had wondered why my cars were always 150+ grams. For months, I studied and devised ways to cut down the weight of all my Open Class cars using materials like car catcher plastic. I later learned that his cars did not include battery weight. When I weighed my cars without batteries, they weighed around 105 to 112 grams, well under his Open Class cars. The moral of the story is if I didn't work on reducing my cars' weight because of my misconception, I would've remained complacent and just copy other people's designs and be like everyone else.

Why should you concern yourself with top speed?
Some racers believe that top speed doesn't matter and the focus should be on stability. That's true for tuned and open class cars. For box stock, you have to concern yourself with top speed. Build the fastest car you can. Make sure all of the parts are lubricated and running smoothly. If it flies off the track, find ways to pare down the speed. You can weigh it down. You can remove lubrication. You can add dust to the tires. It's easier to achieve a successful box stock car this way than the other way around, which is building for stability and then trying to find speed. Some cars are simply not that fast so nothing you do will make them any faster. A seemingly slow tuned or open class car will find speed with the right rollers and weight distribution. There is also the oftentimes ignored consideration of how fast a car recovers its speed after landing from a jump or even a forcible bump. The more you fine-tune a car's transmission, the faster it will recover after such effects.

Racer (Clare) Kit Chassis Class Weight (gms) Box (Km/h) Tuned (Km/h) Open (Km/h) Speed Notes
Blue Beetle
3.5:1 gear, Avante poly body, rear mass damper
Aero Avante AR tuned 97 17BX

30AT Rayovac 8/24/22
3.5:1 gear, slick tires
Flame Astute Red Metallic AR box 86 28BX
27BX Rayovac 7/25/22
28BX Rayovac 9/5/22
26BX Rayo 1.57V 11/9/22
Rayovac, 24k water-tuned motor
AAA Box Stock Bronze (8/22)
HT Box Stock Gold (8/22)
AAA Box Stock Gold (9/22)
4.2:1 gear, 30mm tires
Razorback FM-A box 90 22BX       23k BX, 1.44V
3.5:1 gear, 24mm tires
Mach Frame FM-A BMAX 139   26AT 29HDw
  28k AT, 1.56V
34k HDw, 1.57V
41k HDw, 1.6V (too fast)
Venom FM-A
Mach Frame Black Special FM-A box 85 26BX       28k Venom-tuned motor, 1.54V
aka MachWarrior
3.5:1 gear
Mach Frame FM-A box 85 26BX       Rayovac, CO <4 bodyparts
HT Box Stock Bronze (11/21)
AAA Box Stock Silver (6/22)
LC Box Stock Gold (9/22)
LC Box Stock Bronze (10/22)
3.5:1 gear, 19mm front/rear, trimmed propeller pinions, skid bar front, 2.5g x 2 side mass dampers, 7.5g x 2 rear mass dampers, cab damper with 6.6g x 2 block weights
K4 Gambol FM-A open 142
  34HD   Rayovac, 14g more if car includes Medusa
Shooting Proud Star Clear Blue Special MA box 105 26BX       NeoChamp, oiled motor
AAA Box Stock Bronze
MS Pro Flex suspension, 3.5:1 gear, AT front on rear, reverse catcher lantern, super hard tires
homemade MS open 118   24ATP

  Rayovac NiMH too light
HT Open Class Silver (2/22 ATP)
^^^ v2
3.7:1 gear
  MS open 118  
^^^ v3
3.7:1 gear, Flexi-Plate v1, low frix/superhard sponge tires
  MS open 112  
33HDP Rayo 11/7/22 LDP 1.5V Rayo, HDP 1.38V
homemade MS open    
27LDP 27LDP Rayo 11/7/22  
Black Bear
4:1 gear
Kumamon Racer S2 box 76 22BX       24k Venom-tuned
Green Goblin
4.2:1 gear
Astro Boomerang Premium Black Special S2 tuned 117   22TT      
3.7:1 gear, hollow prop, 12mm disc roller front, 19mm disc rollers rear, Ray Spear wheels
Panda Racer S2 tuned 115
    Fujitsu, gear box pop issue, terrible box stock racer
^^^ v2
side mass dampers, add'l rear weight
  S2 tuned 136
  28AT Rayovac 8/25/22 1.54V Neo (27AT)

^^^ v3
11/13mm front rollers, 24mm tires

  S2 tuned 138
  27AT, 24TT Rayovac 8/25/22 1.54V Neo, 32k AT, 33kTT
AAA Tuned Class Gold (9/22 AT)

Space Ghost
no side damper bar, front brace

Shining Scorpion Premium S2 box 77
    73g without side stay

Venom S2

Neo Tri-Dagger ZMC Carbon Special S2 box 80
    24k Venom-tuned, 78g without tail
red polycarbonate reinforced chassis, carbon fiber canopy, green homemade body and tail damper, Flexi-Plate v2
  VS open 111     31HDb
31HDb Rayovac 7/7/22, 9/5/22
33HDw 34k Rayovac 7/14/22
32HDw 33.8k Rayo 11/8/22
HT Open Class Silver (7/22 HDb, 8/22 HDw)
HT Open Class Bronze (9/22 LD)

aka Pango
5:1 gear

Koala Racer Pastel Special VS box   16BX       box stock is useless
4:1 gear
  VS     19BX
22TT 21LD
  good with LD and 4:1
^^^ v2
3.5:1 gear with ball bearing and fluorine coated shaft, roller spacer, hollow prop, 60mm hollow shafts, brass keylets, carbon wheels, super hard tires, 12-13mm front rollers with rubber rings, 19mm rear alum rollers and tapered rollers, Deluxe Dragon Tail 1mm blue brake
  VS tuned 106   30AT(***)
  27 AT Rayovac, 25 AT Fujitsu
^^^ v3, v3a
hex ball bearings, 60mm carbon reinforced shaft, side mass dampers, block weight rear, pinion pusher stabilizers, purple underguards
  VS tuned 130   30AT(***)
  30AT Rayovc 6/12/22, 9/9/22 27 AT NeoChamp, v3a purple rollers, hollow shafts too delicate, 1.47V Rayovac (28AT)
aka Lupo
3.5:1 gear with ball bearing and fluorine shaft
Lupine Racer VS open 86     25HD    
^^^ v2
  VS tuned 100   29AT      
^^^ v3
  VS tuned 98   29AT     no front weights; repositioned, lowered rear weights
^^^ v4
hi-mount tube stabilizers, homemade underguards, lantern
  VS open 117   26AT



weights front and rear
HT Open Class Silver (3/22 AT)

HD 1.46V



^^^ v5
24mm tires purple/black
  VS open 117    


32HDb Rayo 11/14/22


3.7:1 gear, POM bearings, 8-9mm rollers front, 19mm rollers rear
homemade Frankenstein car VZ open 111     47SD   best run at 40-43SD at 1.43V-1.51V Rayovac
^^^ v2
24mm tires
            39SD 39SD 1.61V Rayo  
4.2:1 gear, laser parts
Jadow A VZ box   26BX       Rayovac, 23k motor
3.5:1 gear, reverse rollers
Dual Ridge Jr. VZ box 73 26BX       Rayovac, 25k motor
3.5:1 gear, reverse rollers

Ray Spear VZ box 71 23BX
3.5:1 gear
Toyota GR Yaris VZ box 81 26BX   28HDw   Rayovac, 22k box motor
Neon Vicky
3.5:1 gear, ball bearings,12-13mm rollers front, 19mm rollers rear, hollow prop, Energizer 1300mAh
NEO-VQS Japan Cup 2020 VZ open 105     35SD    
^^^ Energizer >>> Fujitsu 1.2V 950mAh (June 2021)   VZ open 105     36SD    
^^^ v3
wheel stabilizers, front weights, fluorine coated gear shaft (July 2021)
  VZ open 111     36SD
33 HDw 1.51V Fujitsu 9/5/21 HT Open Class Bronze (7/21 SD)
^^^ v4   VZ open 103     37SD
1.51V Fujitsu and 1.43V NeoChamp HT Open Class Silver (11/21 SD)
^^^ v5
19mm rollers x 4
  VZ open 111     37SD
36SD Rayovac 6/12/22
27LD Rayo 11/7/22
SD 1.32V CO
Penguin Racer VZ drag 80   26TT     retired 5/8/21
^^^ v2   VZ drag 77   31TT     retired 6/12/21
HT Drag Race Gold (5/21, 6/21, 7/21 TT)
^^^ v3
Avante poly shell
  VZ drag 72   31TT     HT Drag Race Silver (8/21 TT)
^^^ v4
hollow shafts, minus one set rear rollers
  VZ drag 70   31TT   31 TT 9/5/21  
Venom VZ
Dual Ridge JCup 21 VZ box 69 27BX       26k Venom-tuned motor, 1.54V
Racer (Matt) Chassis Chassis Class Weight (gms) Box (Km/h) Tuned (Km/h) Open (Km/h) Speed Verified Notes
4,2:1 gear
Shadowshark Italia Special AR box 95          
4.2:1 gear
Copper Fang Black Special FM-A box 90 25BX     25BX Rayovac 6/11/22  
Geometric Vector
3.5:1 gear
Mach Frame Black Special FM-A box 85 24BX     24BX Rayo 11/7/22 HT Box Stock Gold
Blue Wasp Shooting Proud Star Clear Blue Special MA box 105 24BX        
The Midnight
Festa Jaune Black Special MA open 142 19BX


36MD   1.54V Rayovac (27AT)
LC Tuned Class Gold (9/22)
Bumblebee DCR-02 MA box   25BX       HT Kids Box Stock Gold
The Wasp Rise Emperor Black Special MA box 105 25BX       AAA Box Stock Gold
Owl Racer Owl Racer S2 box            
HyperSupreme Dual Ridge Japan Cup 2021 VZ open 105     32HDw
35PD Rayovac 11/7/22 1.54-1.61V Rayovac (32HDw), best run on 1.47V Rayovac (31HDw)
LC Tuned Class Gold (9/22)
Retired Cars Kit Chassis Class Weight (gms) Box (Km/h) Tuned (Km/h) Open (Km/h) Speed Verified Notes

Geo Glider Black Secial FM-A box 90-92 24BX       Rayovac
^^^ v2
ABS green body

  FM-A box* 88-91 24BX     24BX Rayovac 6/15/22 not true box stock since chassis was replaced with lighter version
Bumblebee Festa Jaune MA box 98 22BX       RETIRED
^^^ v2
Festa Jaune poly, 3.5:1 gear, 12-13mm front, 19mm rear, body damper
  MA open 113     32HD   RETIRED
Owlie Owl Racer GT MA box 97 20BX
Exflowly Exflowly MS box 82 18BX       RETIRED
Dinah Shore Dyna Storm S2 box 77 20BX       RETIRED
aka Thunder Zero
aka Frankenstein
redesigned rear, 3.7:1 gear
Thunder Boomerang W10 STZ-X tuned 106   29AT(**)
  29AT Rayovac 6/12/22 AAA Tuned Class Silver (7/21 AT)
HT Tuned Class Silver (9/21 AT)
1.47V (26AT)
RETIRED 7/12/22
3.5:1 gear
Phantom Blade Black Special SXX open 80 23BX 24TT 31PD
23BX Rayovac 6/11/22 mostly Rayovac tests, NeoChamp SD, 39UD
23BX 6/11/22
^^^ v2
rollers, mass dampers
  SXX open 104     27HDb   mostly Rayovac tests, PKCell
^^^ v3
  SXX tuned 80   26TT     Leo tuned HDb

^^^ v4

  SXX tuned 124   26RT    

saves 3g off Phantom Blade body; only 1g more than poly body, 1.54V Fuji (26RT)

TT 1.46V Rayo

Green Hornet
5:1 gear
Dash-4 Cannonball ZERO box 74 19BX       74g Cannonball body, 78g Horizon body
4.2:1 gear
ZERO ZERO box 74 22BX       RETIRED

Note: Weight (gms) is the weight of the car without batteries

BX = box stock, TT = Torque Tuned, RT = Rev Tuned, AT = Atomic Tuned, LD = Light Dash, HDb/w = Hyper Dash black/white, MD = Mach Dash, SD = Sprint Dash, PD = Power Dash, UD = Ultra Dash
CO = car jumped off-course

AT(**) - 7/20/21

Battery weights in pairs, heaviest to lightest:

Rayovac High Energy: 48g
Energizer Max: 47g
Energizer Recharge: 43g
Neo Champ: 36g
Fujitsu Pink: 36g
PKCell Green: 29g

Mini 4WD Kit Rating Index

Ganapati oil $12 a bottle. Perfect for lubricating rollers.
Voodoo oil $12 a bottle. Increases your motor's RPM.
Discount when you buy both.


Guiding our future Mini 4WD generations!



All images and work herein © 2007-2023 Clare Din. No reproduction without permission. All rights reserved.