VehiclesTamiya SW-01

Tamiya SW-01 Chassis

Name: Tamiya SW-01
Brand: Tamiya

1/24 scale · 4WD chassis · sold as kits

Tamiya's SW-01 is a 1/24 four-wheel-drive, gear-driven wheelie chassis small enough to sit in two hands, sold as the Comical Wheelie Lunch Box Mini and Mudmad assembly kits.

Tamiya prints 21.88:1 on the stock 16T pinion and does not publish the spur or the gear train behind it, so the pinion and that total are the only gearing figures. The wheelbase is 92 mm. The pinion, motor and tires come with each kit rather than with the chassis, so enter yours in the gearing tool.

Final drive: 21.88:1on 16T
Wheelbase: 92mm
Introduced: 2019

Gearing Top speedsourced

The pinion, motor and tires come with each kit: enter yours in the gearing tool.

Tamiya SW-01 — Photo: Tamiya (opens in a new tab)

Kits on this chassis Built on the SW-01

Each kit adds its own body, tires, pinion and motor. The chassis figures below apply to all of them.

Kit	Part no.	Maker page
Comical Wheelie Lunch Box Mini (Assembly Kit)	57409	tamiya.comPage (opens in a new tab)
Comical Wheelie Mudmad (Assembly Kit)	57412	tamiya.comPage (opens in a new tab)

Specifications

Last modified Sep 28, 2026

Spec	Value	Basis
Vehicle
Drive All four wheels are driven. That gives more grip under power, especially on loose ground. The cost is more parts to maintain. Build A kit you build yourself from parts. Most kits come without motor, ESC, servo, radio and battery, and many without tires or a painted body. The manual lists what to add. Scale The maker's nominal size compared with a full-size vehicle. It works more as a class label than a measurement. A 1/10 monster truck is far bigger than a 1/10 touring car, so compare length and weight for real size.
Drive	4WD
Build	Kit
Scale	1/24
Drivetrain
Pinion The small gear on the motor shaft. Fewer teeth gear the car shorter: quicker acceleration, lower top speed and a cooler motor. More teeth do the opposite. On a chassis sold as kits, each kit brings its own. Spur The large gear the pinion drives. A bigger spur with the same pinion gears the car shorter. Pinion and spur must have the same pitch, or tooth size, to mesh. Transmission & axle Every reduction after the spur, multiplied together: transmission, differentials and axle gears. It is fixed by the design; the gearing you change is the pinion and spur. Final drive How many times the motor turns for one turn of the wheels. A higher number is shorter gearing: more acceleration and pulling power, less top speed.
Pinion	With each kit
Spur	Not published
Transmission & axle	Not published
Final drive	21.88:1 on 16TMaker's chart	Maker's chart
Wheels & tires
Tire diameter The outside diameter of the mounted tire, tread to tread. A taller tire covers more ground each turn, which gears the car taller. At high speed tires can balloon and grow, so the real gearing gets taller as the car goes faster.
Tire diameter	With each kit
Power
Motor Motor KV is the RPM a motor turns per volt with no load. This vehicle comes without a motor, so there is no stock KV; it depends on the one you fit. Battery The highest LiPo cell count the maker rates the electronics for. This vehicle comes without electronics, so it depends on the ESC and motor you fit.
Motor	With each kit
Battery	With each kit
Size & weight
Wheelbase The distance between the front and rear axle centers. A longer wheelbase is steadier at speed and over bumps; a shorter one turns more tightly.
Wheelbase	92 mm3.6 inStock	Stock

How to read these figures

Stock is as the vehicle ships.
Calculated is worked from the stock figures on this page rather than stored beside them, so the two cannot drift apart.
Not published means it exists but no source we could find prints it.
With each kit means each kit on this chassis brings its own, so enter yours in the gearing tool.
Maker’s chart is the ratios the maker prints for this chassis with the pinions it names.

How these numbers were settled

The SW-01 is Tamiya's gear-driven 4WD Star Unit chassis with a 370 motor and planetary differentials.

Tamiya publishes neither the spur tooth count nor the ratio of the gear train after it: the Lunch Box Mini manual (57409.pdf) shows the 16T pinion (step 3, p. 5), and its options box (p. 22) says 16T and 18T pinions fit (SP.354 16T/17T, SP.355 18T/19T) without printing their ratios.
Both kit pages print 'ギヤレシオ=21.88:1', which is the kit's 16T pinion, and a 92mm wheelbase.
Kits: the Lunch Box Mini assembly kit is a standard product and the Mudmad assembly kit a spot re-run first sold in 2020 (std.csv); the built-up versions (57410, 57413) are left off.
The pinion, motor and tires come with each kit, so they are not part of the chassis figures: enter yours in the gearing tool.

Sources

Every figure on this page traces to one of these; where they disagreed, the note above says which was used and why. Links open in a new tab.

Maker documents

Comical Wheelie Lunch Box Mini (SW-01) instruction manual (Tamiya PDF) (opens in a new tab)16T pinion step 3 p. 5; pinion options p. 22d7z22c0gz59ng.cloudfront.netUsed forMain specs

Parts and electronics

Product info EX (opens in a new tab)tamiya.comUsed forMain specs
Products 57409 (opens in a new tab)tamiya.comUsed forMain specsSize
Products 57412 (opens in a new tab)tamiya.comUsed forMain specsSize
Products 57412 (opens in a new tab)tamiya.comUsed forMain specsSize
Std.csv (opens in a new tab)tamiya.comUsed forMain specs

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