Elimination of stack preload due to bent shims can be very difficult. Bent shims on the order of one tenth of a thousands of an inch (0.0001") is nearly impossible to measure. Yet, in a stack of 30 shims allowing each shim to be bent by 0.0001" produces a stack preload of 0.003" and a substantial change in the low speed damping forces produced by the shock. Bent shims, dirt in the stack and defects in the valve face are some of the unquantified unknowns that cause dyno tuners to state that they cannot setup two shocks to produce the same damping force.



