We are often asked to manufacture raked triple trees. Our decision NOT TO RAKE TRIPLE TREES revolves around the stability and handling of the bike, and the safety of you, the rider. Raked triple trees are scientifically unsound, as explained below.

As trail is REDUCED, instability results, producing a natural tendency towards deflection or speed wobble.

As trail is INCREASED, so does the ability of a motorcycle to resist wobble and follow a straight line. There is a limit, however - too much trail can result in a motorcycle only being able to travel in a straight line!

TRAIL is geometrically determined by continuing a centerline through the frame head to the ground, and drop- ping a vertical line from the center of the axle. The difference between the 2 points (corrected to the centerline of the motorcycle) is measured in inches.

THREE DIFFERENT FORK CONFIGURATIONS SHOWING HOW TRAIL IS AFFECTED

A) Typical Stock Configuration
A 30° rake is established in the frame head. The fork is also at 30°, with no rake change evident in the triple trees. The trail is lets say 3.5"

B) Raked Triple Tree
The Frame Head remains unaltered at 30°. The triple trees are machined to produce 35° in the fork. The trail vanishes to zero degree, producing gross instability.

C) How it Should Be Done
>The components are the same except that the Frame Head is reconfigured to 35°. The altered geometry increases the trail to let's say 4.25 inches and produces more straight-line stability.

So what's the solution? We recommend altering the frame head in order to achieve the desired non-standard rake. Never consider the "easy way out" by choosing raked triple trees. We would caution the rider to seek professional help in selecting a precision jig and only using sound, careful welding procedures.

Glossary

RAKE: The angle of the fork tubes, expressed in degrees off vertical. Also: CASTER

TRAIL: An imaginary distance arrived at geometrically, expressed in inches.

FRAME HEAD: A tubular section of the frame that houses the assembled fork stem and bearings. It is a normally immovable part which establishes the rake of the fork.

TRIPLE TREE: Machined, forged or cast plates which contain the fork tubes and fork assembly. Usually no rake angle is established here.