Spring preload affects a motorcycle’s ride height and steering geometry. A change in rider or luggage weight can therefore call for a setup check. The starting point is sag: how far the suspension compresses from its fully extended position.
The principle is to compare the same reference points in three conditions: suspension unloaded, motorcycle resting on its wheels, and rider aboard in full gear and a normal riding position. The first reading minus the second gives sag under the bike’s own weight; the first minus the third gives rider sag. Lifting requires a suitable, stable stand, and measurements require level ground.
Compare the results with the instructions for the particular motorcycle and fitted suspension. Another model’s millimetres or adjuster clicks are not universal targets. Make one small change at a time and record it. If the recommended ride height cannot be reached within the permitted preload range, a suspension specialist should assess whether the spring is appropriate.