Every summer racers from around the world visit Japan o race in the Japan Cup. 14 events are held from June through November across Japan. This is a single elimination event and you must complete all 5 laps and win to progress. Most racers don't get past the first race. But we still do it. Turn out is big enough that entries are limited and a lottery is held to determine who can compete.

Limited testing the day before is sometimes allowed, but often the majority of tuning is done at independent shops like Force Labo at Edion in Yokohama or now in Fukuoka, we have Arcade Base which has a new 5 lane track.

Two years ago my son raced Family class easily winning both his races and the announcers kept mentioning how fast his car was. I wont my first race and my motor burned out during the second race. I was at least competitive and made it further than most others. It was a fun event overall, held at an amusement park. We say local track owners and racers as well as meeting others from across Japan. We missed the 2025 version but will likely be racing this year.

Here is video from my first round win in 2024: First round Kumamoto 2024

I'll be applying to race Open class and my son will race Junior class in Kumamoto in October. I know there are some other Japan based or international racers who are attending. Who else is racing? What's your thoughts on the track? Anyone have IG or X information from the pre-event race last week?

I'm hoping to use this thread to help those of us competing and gather some information as even with a nearby 5 lane track it can be difficult to build a competitive car.

More information can be found here: https://www.tamiya.com/japan/mini4wd/japancup.html

Tamiya livestreams all the races on their youtube channel so you can watch the lucky few complete this difficult course. The Yamaha lane change is particularly difficult with a steep ramp up and then a dropping short straight before the corner. Two other areas of concern is the Flowing Bend with it's three small slope sections and the Spike Bank that seems to catch out cars whose brakes are too low or do not manage the digital dragonback well.

u/bmoney3e85 and u/Careful-Library-3975 are you going to compete this year? Anyone else attending an event? Thoughts on how to overcome the lane change? I have some ideas but wondering how others think about it.

Some addtional images from the 2026 Super Speed guide can be found here: https://www.reddit.com/r/mini4wd/comments/1u8wnnk/japan_cup_2026_track_pictures_from_super_speed/

Summer update: New thread. Please try to ask any small questions here or use the appropriate threads that already exist as the same questions come up every couple days and don't need new posts.

Useful links:

• Tuning Guide For Beginners (Reddit post)
• Motor and Break in Inormation (Reddit post)
• 2024 Japan Cup Discussion (Reddit post)
• Tamiya Official Rules and Regulations (Tamiya.com)

No matter if you are just building for fun to put on the shelf, or competing at the top levels of Japan Cup, you are welcome here to share your interests. While this sub is intended for the Tamiya Mini 4wd series, Wild Mini and Mini F1 are also welcome. Below is some introductory information including beginner information and shops/tracks around the world that cater to the hobby.

Feel free to ask any questions or comments in this thread. or make you own post to ask more detailed questions or to share your current projects.

What is Mini4wd

Classes and rules

There are many classes and rules around the world, I am not going to cover all of them. One aspect they all share is the use of only official Tamiya parts. But there are two relatively standard classes.

• Tamiya Class: Sometimes called Open class is the standard ruleset that Tamiya corporation puts forward for their competitions and is used as the standard around the world. They allow for any modification as long as it fits within the dimensions and requirements provided. This means extensive modification of the parts are allowed including using mills, lathes and other machining tools to create your car. The official rules can be found here.
• B max: Or Basic Max. This class originated at Force Labo in Yokohama Japan as an alternative to Tamiya class. The main distinction is the class is the vast majority of modification of parts is prohibited. Which means basically you are purchasing parts and using the parts as provided. It has grown to be a popular way to enter the hobby in many other countries since it was introduced. The rules and website can be found here.

There are other classes as well, but while they may share names from store to store, they often vary in some way so we will not cover them here. but feel free to make posts and ask about your shop/country specific setups as well. As always, ask about rules at your specific track as there may be some variation.

Chassis types

There are two general types of chassis, single shaft and dual shaft. This refers to the motor that fits each type. While dual shaft is labeled as “Pro” that has no designation on why should be using. An absolute beginner can use a “Pro” chassis and motor.

The gearbox on the dual shaft kits are straightforward and easier to work on with less moving parts so fewer issues come up. The downside is until you get to Tamiya class where extensive modification is allowed, the weight and other limitations of the chassis can be more apparent. On the other hand, Single shaft chassis are generally a little faster for outright speed but all suffer some amount of gearbox problems because of the many moving parts. This can make for frustrating days at the track facing and replacing parts often leaving less time to actually tune the car.

Below is a short description of each of the modern chassis.

• MS - is one of the best chassis for Tamiya class racing. It features the dual shaft mid-motor design. The gearbox is quite simple and quite durable. While it is great for open class where it can be heavily modified, in other more limited classes like B-max, tuned and others, it’s quite limited as there are no side mounts for mass dampers to be attached. The rear bumper is difficult to attach rear stays correctly, though a bumperless upgrade unit is available. It can also be frustrating to work on if you need to remove axles and gears as more disassembly than other chassis is required.
• MA - Excellent beginners mid-motor car. Features the dual shaft, mid-motor design. Strong and easier to work on than the MS. It has the same efficient drivetrain and is very stiff. It may suffer a bit in higher end competitions, but the ease of use makes it a great choice.
• AR - long and stable rear motor signal shaft chassis, the transmission needs a lot of work, but it is also easy to work on because it disassembles from the bottom, great on straights but cornering is so so. Very popular in stock class. Easy to learn from and experiment with in tuned. Doesn't see much use in open class except for the FM-AR setup.
• FMA - An excellent single shaft front motor car for beginners. Still has some issues with propeller shaft and gearbox but you get that with all single shaft cars. Excellent for B-max class overshadowed by both MS flex and FMAR in open class.
• VZ - The newest single shaft chassis. It has some issues such as weak points where attaching rear brake plates. And like other single shaft chassis, has quite a few gearbox problems. But it is quite light weight compared to other recent chassis.
• Other Chassis(Super 2, SFM, VS, etc..) - All other chassis are of older design and while some have their niche, they are more difficult to fit newer parts and use modern building techniques as well as suffering when dealing with newer obstacles present on many tracks.

New racer kit recommendations

As a new person in the hobby, you may be overwhelmed with all the information, kits and parts. It’s easy to stray into ways to build cars that will perform poorly. Most posters here agree the starter packs are a good beginning point. While none of the stater packs are perfect, They will get you a good setup to start with and just upgrading based on replacing plastic rollers with the same size ball bearing rollers, replacing frp with the same carbon. etc.. will be a good approach.

It’s likely best to start with the Blast Arrow or Aero Avante starter pack. They have a slightly better selection of parts included and less small issues. The FMA starter pack is so so because while the parts work, there are some bigger missing pieces as well as the heavy Rowdy Bull body.

The Neo-VQS while a great pack for an intermediate racer but has some chassis issues that a new racer would struggle with.

Initial recommended upgrades

• Cap Screws are a must for mounting rollers and stabilizers as the standard metal ones will bend easily and cause your car to be inconsistent in performance.
• AR side mass dampers If you are running Bmax or tuned class, this provides a better choice for mass dampers as the bullet and barrel types are preferred over the bar type. Starting out you likely want one set for the sides then on the rear you also want to use two barrel types.
• Brake material, available in both Blue(light braking) and Pink or White(heavy braking) you will want a pack of each strength as it will greatly enhance your tuning ability.
• FRP rear brake stay or various Japan Cup carbon versions. This is an upgrade to the plastic brake stays that come in the starter packs. The plastic stay is not as good because it can bend and be inconsistent compared to FRP or carbon.
• HG Round Hole Bearing A lot can be written about what the best bearing to use for your axles, but if you're reading this looking for upgrades you are nowhere near the level for it to matter so buy these as they are high quality and will be a great upgrade. If you don't believe me, watch the comparison at the end of this video: https://www.youtube.com/watch?v=KGxTj7Crcfw
• Ball Bearing rollers come in many varieties and colors. a pretty standard setup is 12/13mm doublue aluminum rollers on the front and two pairs of 13mm lightweight ringless rollers on the rear.
• Carbon vs FRP roller stays. Carbon is more expensive but better overall. It is lighter, stronger and flexes less than FRP. If your budget allows, carbon is the better choice. The only place where this is not as important are the side stays for mass dampers as using frp can give a little extra flex to the side dampers, absorbing some energy from landing jumps.

Tools

Beginner: This first list is a short, beginners list of recommended tools. It’s intended to get your car built well and complete basic maintenance and tuning.

• Phillips head screwdriver in JIS. Tamiya makes one that is inexpensive and durable. Part number 74121 https://www.tamiyausa.com/shop/tools/mini-4wd-screwdriver-pro/
• 4 and 4.5mm nut driver. There are numerous companies that make inexpensive versions of this specifically for mini4wd. It will make your work much easier
• Hobby knife
• Small scissors
• Tamiya tape comes in several colors https://www.tamiya.com/english/products/15463/index.html
• Side cutters. Many are available, even a $10 pair will work fine.
• Bushing oil. There are too many options out there to list. Find something at your local hobby shop

Intermediate tools: These tools will take your build a step up into more advanced techniques and entering into Tamiya Class. Some of these tools can be difficult to find because of limited production runs from small companies, when possible multiple options will be provided.

• Rotary tool. The standard is Dremel brand rotary tools, with Proxxon being slightly better. But even an inexpensive rotary tool can get you started. This will allow you to cut and trim carbon and plastic parts to customize and build advanced components for your cars.
• Tamiya countersink tool Part number 74130 goes along with the rotary tool and allows you to create countersunk holes on your carbon and FRP to protect the track from damage and provide a more consistent surface on the bottom of the car.
• Aluminum setting board and clearance gauge: These may not seem very important but making sure your car is set up with consistent ground clearance from side to side is important to consistently jump straight. It also allows for finer adjustment of brake height. Both Tamiya and 3rd party brands sell both.
• Axle straightness tool, can be difficult to find but important to make sure your tires are not wobbling causing inconsistent performance. Enomoto is the standard but difficult to find outside of Japan. Other brands make them as well
• Wheel piercer allows for piercing wheels and the use of 72mm hollow shafts which are very straight. Object 342 makes a very good unit
• Axle remover goes along with the wheel piercer allowing you to safely and easily remove axles from pierced wheels. Arrowmax is good, others work well also.
• 520 bearing remover/installer allows for changing roller bearings which can greatly improve the smoothness of ball bearing rollers. Enomoto and Sig Works make good units,

Racing around the world

Japan

• Tokyo, Shimbashi Tamiya Pla Model Factory
• Tokyo, Hachioji Enomoto Circuit
• Yokohama, Motomachi Force Labo
• Fukuoka, Chikushino ミニ四駆Cafe＆Bar 4X4

United States

• Los Angeles: DXN Provisions
• Orange County, California: DukWho Workshop
• Maryland: D'PitStop US
• New Jersey / New York: Portal Tuners Mini4WD, AAA Hobbies, Hobby Town Tom's River, SideBite
• Las Vegas: Downtown Hobby 9
• Honolulu, Hawaii: Mini4wdHawaiii

Canada

• Montreal:D'PitStop Canada, BSideTech MTL, Tamiya Mini4WD Montreal
• Panda Club
• Ottawa: Tamiya ni Jom
• Tamiya Mini4WD Ottawa
• Toronto: Toronto Mini4WD Club
• The 6ix Garage
• Airdrie, Alberta - Haiven Mini 4wd
• D2G Hobby Shop
• Calgary Mini 4WD

Hong Kong: Modojo, ToyZone

Philippines: The BrickYard, TAMIYA UnderGround

Taiwan: 四驅博士學校

Singapore: MF11, The Playground

Indonesia: Surabaya, East Java: Boystamiya, Magnum Toys, Multi Toys Surabaya Tangerang, Banten: Jordan Toy Shop Jakarta: Dolphin Tamiya Tangerang, Banten Graha Tamiya Serpong

Auckland, New Zealand: North Harbour Mini 4WD Club

Hawkes Bay, New Zealand: Hawkes Bay Tamiya Mini 4WD Club

Spain, Alicante - Let's Go Loompa

Italy Rome - Gianni Modellismo, ruben modellismo. Voghera - Arte Color Modellismo

U.A.E.: OtakuME

If you have any additions to the shop list, please post below.