Frame Geometry - Cut once measure twice

With the back wheel installed on the bike vice, the target ride height is set. Using blocks of wood, the frame in then leveled with the table. A ratchet strap is used to keep the frame locked into place.

Using a plum-bob, the frame center line was measured and translated onto the table. The placement of the stock neck was also marked. The center line will be used during the frame stretch and rebuild process.

Using a square, the stock rake was measured at 30*, stock softtails range from 31* to 33*. The difference here is that the frame is now parallel to table. Stock softtails have a 1* to 3* incline. Using simple maths, the rake can be calculated to 30*. Horizontal(x) = 3.5, Vertical(y)=6. ATAN (x/y) = rake

Various points on the frame were measured and entered into the computer. The black indicates the frame parts that will remain stock while the purple represents frame parts that can change. The current fork tubes are 2" over and the new ones 10" over. These are drawn in the upper corner. The computer allows for changes, in rake, trail, upper and back bone stretch without making any welds. This is the target frame geometry we plan to use.

The pictures are article on this page were kindly provided by www.jhchoppers.com

If you have written an article and would like it to be published, please contact us; webmaster@motorbike-search-engine.co.uk