Kyosho MINI-Z Buggy Inferno MP9 TKI

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.

Ready to run: built at the factory with the electronics installed.

• Some come without a battery or charger; the maker's box contents say which.

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 9.1%.
• A bigger pinion loads the motor and ESC harder, so check the maker's gearing chart and feel the motor temperature after a run.

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.

Spur teeth divided by pinion teeth: the part of the gearing that a pinion or spur swap changes.

• Here it is 3.182:1.

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.
• This one is worked out from the tooth counts the maker publishes.

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.

Front rollout divided by rear rollout, minus one, expressed as a percentage at equal axle-input RPM.

• The listed front and rear rollouts match at equal axle-input RPM. The connection between axle inputs is not recorded, so its ability to accommodate a mismatch is unknown. These figures do not predict vehicle road speed.
• Positive means the front covers more distance per input turn. Zero means matching rollout, rather than matching wheel RPM.

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.

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.

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.

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

A transmitter comes in the box, already bound to the car's receiver.

No drive battery comes in the box.

• Buy one with the right plug and a cell count the ESC is rated for (the Battery row under Power).

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.