XRAY XT8E'24 Chassis

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.

• A truggy is a 1/8 buggy with wider arms and truck tires: more stable and more forgiving on rough ground.

Sold without a motor, so you choose the motor, ESC and battery yourself.

• Rows that depend on the motor say so.

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 a chassis sold as kits, each kit brings its own.

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 Gearing parts table below shows this car's pitch and part numbers.
• On this car the spur is mounted on the center differential.

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.

Silicone oil sealed inside the differential. A diff lets the wheels on one axle turn at different speeds in a corner; thicker oil makes it act more like a solid axle.

• At the front, thicker oil keeps both front wheels pulling out of a corner but makes the car turn in less willingly; thinner oil steers more easily.
• It is graded in cSt (centistokes), a measure of thickness that means the same across brands. K means thousands, so 10K is 10,000 cSt.

The center diff splits power between front and rear. Thicker oil there sends more drive to the end that has grip and helps acceleration; thinner oil lets the car steer more easily off the throttle.

The rear diff mostly shapes drive out of corners.

• Thicker oil there puts power down more evenly on loose or slippery ground; thinner oil lets the car rotate more easily through a corner.
• This car runs thicker oil in the front diff (10K) than the rear (5K): steadier on turn-in, with a rear that lets the car rotate.

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 hex on the axle that the wheel locks onto and is driven by. A wheel must match the hex size to fit.

• 17 mm is the standard size on 1/8 cars.
• The wheel nut is a separate size, so check its thread too before buying nuts.

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.

It needs a motor KV, and this vehicle comes without a motor. Fit one and the calculator works it out from the motor's KV and the gearing.