Trail (for motorcycles)

Description

Trail, or caster, is the horizontal distance from where the steering axis intersects the ground to where the front wheel touches the ground. The measurement is considered positive if the front wheel ground contact point is behind (towards the rear of the bike) the steering axis intersection with the ground. Trail is a function of steering axis angle, fork offset, and wheel size. Motorcyclists tend to speak of trail in relation to rake angle. The larger the rake angle the larger the trail. A rake is an angle of slope[ and for motorcycle is measured from the vertical.

Related formulas

Variables

TmotoTrail (mm)
RWWheel radius (mm)
ArThe rake angle measured from the vertical (radians)
OsThe fork offset or rake (connects a motorcycle's front wheel and axle to its frame) (mm)