HOW TO : UNDERSTANDING MOTORCYCLE RAKE AND TRAIL

            Spec charts sometimes quote rake and trail numbers for a motorcycle chassis, but what does this mean? If you ask, you feel like you’re getting sent on some sort of snipe hunt. Not to worry, I am here to share knowledge. And the concepts, while abstract, make perfect sense when you see them.

         Rake (also called caster) is the angle of a motorcycle’s steering head of the frame (A). Choppers have a lot of rake—their forks stick way out in front. Super bikes have much less astheir forks are closer to vertical. A typical sportbike might have a rake as steep as 25 degrees, while a chopper may be closer to 45 degrees. A touring bike is typically at around 29 degrees and a cruiser at 32.

        More rake does two things: one, it makes the wheelbase longer, and two, it generally increases a motorcycle’s trail.

          Trail (B) is measured in distance (inches or millimeters) between the point of the front wheel’s contact with the ground and a line drawn through the axis of the steering head.

         Under normal operation, this contact point is always some distance behind the projected line: somewhere between 2 and 4 inches (5–10 cm). Think of it as how far the contact patch trails behind the steering axis. Too much trail makes a motorcycle difficult to turn; too little makes it unstable.

        Comparing the rake and trail numbers for different motorcycles may give you some idea of how they’re going to handle, even if you’ve never ridden them.

("Good luck maintaining your own bike" well, she said that.)