Alignment

Once a chassis has been measured, it may need to be aligned. This step is very important in both crash repair and handling optimization. A chassis that is not square and true has the suspension planes and axis skewed relative to the swing arm pivot axis, thus setting up a scissor type motion of the suspension as viewed from the back. The chassis then "winds up" or rotates as viewed form the top. This twisted suspension motion sets off problems such as head shakes, pulling one side, turning better to one side or the other, and for racers a straight chassis grips better and is more predictable to ride at the limit.	The greater the suspension travel, the more critical the alignment is to good handling. This makes alignment of off-road bikes even more critical as the long suspension travel makes them more susceptible to swapping, due to the increased lateral displacement. To correct a twisted frame or swing arm, the chassis is loaded in a correction jig and held tight. Braces are placed around the chassis and jack screws and hydraulic rams are used to draw the chassis into alignment. Incases of severe misalignment, heat may be used to relax aluminum or stress relieve steel.

Front end alignment is just as critical as the frame and swing arm. We spend considerable time on the front end assembly before it is installed on the frame. It is critical that the fork tubes be in perfect alignment in all three planes or the forks will bind.	Since all the parts in the front end are not made identical, it takes some expertise and patience to assemble correctly. Improper assembly is one of the leading causes of stiction and binding in the front forks.