Karts may appear to be miniature cars, but they differ from ATVs and other miniature vehicles in a few key ways. There is no traditional suspension in a kart, so while things like camber and caster may be adjustable, there are no dampers or springs. This seems to be due to the axle being permanently attached to the frame, the absence of a differential, and the fact that both rear tyres turn at the same speed. A driver sits next to a small engine, usually 125cc or less, that drives the rear axle with either chains or gears in most kart layouts.