Originally Posted by
CliffordK
On a flat, level floor, with round wheels, the contact point has to be directly below the hub/axle. Think about it. No need to even have the bike attached.
Dancingbear linked to the Wikipedia article about
Bicycle Geometry
Trail and Rake are measured with respect to an imaginary line drawn down from the center of head tube.
Um, Clifford, are you saying my suggestion was off-base? Please explain. I have measured trail directly in the past, and i find it challenging. I find it much easier to measure the key parameters (offset, angle, diameter) and then calculate the trail. But for the Diamante, the OP cannot take either approach. But if he can give a frame builder an axle to head tube required length and a reasonable target value for trail, he can get a fork built. Or he can dump the frame on the builder and say "please make me a fork that would steer like ... (insert description), he can get a fork built.