MST RMX 4 RTR MTRTR 275

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.

• Drift cars are set up to slide through corners on hard plastic tires, with the rear wheels turning faster than the front or driven alone.

Only the rear wheels are driven.

• Modern drift chassis are mostly rear-wheel drive and use a steering gyro to hold the car at an angle through a slide.

A brushless motor has no brushes to wear, so it makes more power and runs more efficiently than a brushed one.

• It needs a brushless ESC.

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 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.

• 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.

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.
• On a belt-driven drift chassis it takes in the pulley ratios as well.

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.

• Drift cars are geared for fine throttle control through a slide more than for top speed.

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

• Drift tires are hard plastic and barely change size as they wear, so the gearing stays put.

Motor KV is the RPM a motor turns per volt with no load.

• The maker does not publish it.

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

• The maker does not publish it.

It needs a motor KV, which this vehicle does not have on record, so no theoretical top speed is worked out.