This is a GENERAL DESCRIPTION of rake trail. Optimum measurements vary from bike to bike. There are many other factors also involved which are not discussed here.

OFFSET: Centerline of the top steering neck(stem) to the centerline of the top of the fork tubes.Diagram

RAKE: The angle in degrees of the steering neck from vertical .

FORK LENGTH: The distance between the top of the fork tubes to the centerline of the axle.

DIAMETER: The diameter of the front tire.

TRAIL: The distance defined by the vertical line from axle to ground and the intersection of centerline of the steering neck and ground.

RAKED TRIPLE TREES:High degrees of neck rake coupled with various fork designs can sometimes lead to excessive trail measurements. In order to bring trail figures back into line, triple trees with raked steering stems can be used. Usually adjustable in 3, 5, 7 degrees of rake.

HOW TO MEASURE CORRECT TRAIL

With the bike in an upright position, using a level upright, hold the level straight down from the center of the front axle nut to the floor. Put a mark on the floor at that point. Then hold a string or a suitably long straight edge parallel to the centerline the steering neck, following the angle of the steering neck all the way to the floor. Put a mark here also. Now measure the distance between the two marks and you have your trail measurement. It should read between 3 and 6 inches.

TOO LITTLE OR NEGATIVE TRAIL

With too little or negative trail (steering axle mark behind the front axle mark), the bike will handle with unbelievable ease at low speeds, but will be completely out of balance at high speed. It will easily develop a fatal high-speed wobble. EXTREMELY DANGEROUS!

NORMAL TRAIL

Normal trail is somewhere between 3 and 6 inches. The bike will handle easily at both high and low speeds. Flowing smoothly through curves without swaying or wobbling. If you use a very fat rear tire, you should keep the trail as close to 5 inches as possible.

TOO MUCH TRAIL

If the trail is more than 6 inches the bike will begin to handle sluggishly at high speeds. It will seem almost too steady. You will have trouble balancing the bike at lower speeds or on winding roads. It will feel generally sluggish and clumsy.