What drivetrain part do karts lack, requiring one rear tire to slide in corners?

Karts lack a differential, so one rear tire must slide or lift slightly while cornering.

A differential normally lets wheels on the same axle rotate at different speeds. That is important in a turn because the outside wheel travels farther than the inside wheel. Most karts instead use a solid rear axle with no differential, a simpler and lighter arrangement that transfers engine power directly to both rear wheels.

Without a differential, the rear tires cannot naturally follow different cornering paths. Kart chassis are therefore designed to flex and lift the inside rear wheel slightly during a turn. This reduces the inside tire’s grip and allows it to slide or leave the track surface, helping the kart rotate through the corner.

The absence of a differential is a defining mechanical difference between many karts and ordinary passenger cars. The sprocket and chain transmit power to the rear axle, but they are not substitutes for a differential. A radiator and carburetor perform unrelated cooling and fuel-metering functions.