Trail

he may be asking about trail in the front forks.....and ya need more input than the question asked.....lots of things to consider....

1. Rake angle is the angle of steering axis as compared to vertical.
2. Given the relationship and interaction between rake, trail,
load distribution and centers of gravity it would be very
hard to accurately define the function of rake alone.
a. It is generally agreed that a vehicle with:
1) "MORE" rake will have straight line stability and
be somewhat harder to steer.
a) The castor (self centering) effect on the front
wheel is dependant on force created by
"lever arm" action ("length" of lever arm).
(1) Positive rake reduces length of "lever arm".
(2) Positive rake also reduces the steering angle
between tire and ground, as compared to angle
to which the handlebar is turned. In theory, this
would also reduce the "length" of lever arm.
(a) Therefore we need more trail as rake angle
is increased.
(b) The castor effect can become negative with
large steering angles. In this situation the front
wheel is attempting to push itself to a
point behind the steering axis.
1) At smaller steering angles there is some reduction in trail.
A larger amount of trail may be initially required to overcome
the negative castor effect of additional rake.
2) "Less" rake will have less straight-line stability and be somewhat
easier to steer.

i was just trying to decifer your question.....and it seems to have helped, as you got good answers..................

I thought he was asking about a medium wight gal for the back of his dirt bike to ride trails with