Wheelbase is one of those things that seems obvious but . . . isn’t. It’s just the distance from the front wheel to the rear, right? Wrong.
Wheelbase is the distance from the point where the front wheel touches the ground to the point where the rear wheel touches the ground. You might visualize wheelbase more easily as the distance from the center of the front wheel to the center of the rear wheel.
Touring bikes and cruisers tend to have longer wheelbases, while sportbikes are much shorter. They are built this way becaue bikes with longer wheelbases tend to be more directionally stable, while those with shorter wheelbases tend to be more responsive to steering input. A dragster (or drag bike) is the perfect illustration: the extraordinarily long wheelbase helps keep it running in a straight line.
A long wheelbase makes a bike less wheelie-prone, and because the rider sits farther from each wheel, he gets a smoother ride. But for any given speed, a rider will need to lean a long-wheelbase bike further into a turn—another reason roadrace machines tend toward shorter wheelbases.
Adjusting your bike’s chain may alter your wheelbase by up to an inch (2.5 cm) as well—something many riders won’t notice.