Tamiya The Grasshopper (1984)

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 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 389 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.

• It depends on the motor you fit, so the maker does not list one.

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.

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.

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.

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.
• This is from one outside source, not the maker's own page.

What the shocks are and how they are built, as the maker describes them.

• Oil-filled shocks damp with silicone oil; friction shocks, found on some entry-level cars, damp with a sprung plunger and cannot be tuned with oil.

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.

The electronic speed control. It feeds power from the battery to the motor as you work the throttle, and usually powers the receiver and servo too.

• An amp figure in its name is normally the maker's continuous rating.
• A brushed ESC cannot run a brushless motor.
• Set its low-voltage cutoff for LiPo, so a pack is not run flat.

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

• 380 is a standard can size; a larger number is a longer can with more torque.

Battery pack configuration: A documented battery, motor, or ESC installation detail. Electrical ratings and physical fit are separate checks.

Servo mounting space: A documented servo or steering interface for this model. Matching torque alone does not establish mounting or horn fit.

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.

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.