Tamiya The Fox (1985)

The kind of vehicle the maker sells it as. It sets what the car is built to do and which cars it is fair to compare it with.

• Buggies are low, light off-road cars built for jumps and fast corners on dirt, clay or turf tracks.

Only one axle is driven, the rear on almost every 2WD RC car.

• It is lighter and simpler, and it takes more throttle control on loose ground.

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.

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.

The maker's product number for this exact version.

• A V2, a new color, or a kit instead of an RTR usually has a different number, and parts can differ between them.
• Check it against your box or receipt before ordering parts.

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 this car one tooth changes the gearing by about 6.7%.
• Racers change the pinion to suit the track and the class's motor rules, and often compare setups by rollout rather than tooth count.

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.

Whether the front axle is driven by the motor.

• Unpowered wheels can have tire dimensions but have no motor-to-wheel gear reduction.

Whether the rear axle is driven by the motor.

• The calculator uses this axle's own tire size and complete recorded gear path.

This axle is unpowered and has no motor-to-wheel drive ratio.

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.

This axle is unpowered and has no motor-to-wheel drive ratio.

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.

How the driven axles are connected.

• The coupling has not been established from a source. It is not inferred from 4WD or from the axle differentials.

The outside diameter of the mounted tire, tread to tread. A taller tire covers more ground each turn, which gears the car taller.

• This figure is not from the maker's documents, so treat it as close rather than exact.
• Race tires wear down over a day, and a smaller tire gears the car shorter.

The outside diameter of the mounted tire, tread to tread. A taller tire covers more ground each turn, which gears the car taller.

• This figure is not from the maker's documents, so treat it as close rather than exact.
• Race tires wear down over a day, and a smaller tire gears the car shorter.

The outside width of the stock tire on the front axle.

• Width and outside diameter are separate measurements; neither is the wheel's bead diameter.

The outside width of the stock tire on the rear axle.

• Width and outside diameter are separate measurements; neither is the wheel's bead diameter.

This axle is unpowered and has no motor-to-wheel drive ratio.

Distance at the rear axle per motor turn through its recorded gear path.

• This follows the listed gear reduction and tire diameter; it does not account for tire slip or deflection.
• The selected axle has missing tire or gearing inputs.

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.

The diameter of the motor's output shaft, which a pinion's bore must match.

• This vehicle comes without a motor, so it depends on the one you fit.

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.

The motor fitted at the factory, as the maker names it.

The size of the stock motor's can, as the maker names it.