Wheelbase

The wheelbase is the distance between the centres of the front and rear wheel axles, measured with the bike upright. It is one of the main figures describing a chassis, together with rake, trail and weight distribution.

A longer wheelbase usually means more straight-line stability, less tendency to wheelie and a calmer ride, typical of cruisers, tourers and drag bikes. A shorter wheelbase makes the bike turn more readily and change direction quickly, as on sports bikes, supermotos and trials bikes.

On chain-drive bikes the wheelbase changes slightly when you adjust the chain or change sprocket sizes, as the rear axle moves in the swingarm. Racers sometimes use this to fine-tune handling, but any change should be small and matched with correct chain alignment.