Tamiya Hotshot II BLOCKHEAD MOTORS

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.

All four wheels are driven. That gives more grip under power, especially on loose ground.

• The cost is more parts to maintain.

A brushed motor carries current through carbon brushes that rub on the commutator.

• It is cheaper and smooth at low speed.
• The brushes wear and the motor loses power over time.

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.
• This one is 390 mm long.

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.

The type of each differential, as the maker states it.

• A gear or ball diff lets the wheels on one axle turn at different speeds in a corner; a spool or locked diff turns them together for straight-line drive and climbing, at the cost of steering.

The pinion sizes the maker lists for the stock setup.

• Going larger than the maker's limit gears the car taller than the motor and ESC are meant to run, which risks overheating them.
• The Target pinion calculator shows what each size does to speed.

Whether the front axle is driven by the motor.

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

Whether the rear axle is driven by the motor.

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

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.

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.

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.

• Among 1/10 buggies in the catalog, the middle half run between 8.2:1 and 10.0:1 on stock gearing; this one is 8.7:1.

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.

• 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.

Stock tire width: A documented stock wheel, tire, or axle measurement. Stock dimensions alone do not establish the largest size that will clear the body and suspension.

Distance at the front 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.

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.

What the main chassis is made of and how it is built, as stated for this car. Braces, stiffeners and skid plates are not counted.

• Composite is the makers' word for molded plastic, usually nylon with glass or other fibers: it flexes and shrugs off hits, and it is light and cheap to replace.

Brushed motors are commonly described by can size and turns. No motor KV is published for this vehicle; turns alone cannot supply an exact value.

The highest LiPo cell count the maker rates the electronics for.

• The maker does not publish it.

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

• Brushed motors are often named by can size, such as 540 or 550, and by turns: fewer turns is faster.

Overall length as the maker states it, usually with the body fitted.

• Useful for comparing real size, since scale labels are loose.

Overall width as the maker states it, usually with the body fitted.

• A wider car is more stable in corners and harder to roll over.

Overall height as the maker states it, usually with the body fitted.

• Useful when checking it fits a shelf, a bag or a car trunk.