Originally Posted by
dr_lha
BB30 doesn't really have adjustable pre-load like, say, Shimano Hollowtech cranks or headsets do though does it? Pre-load is supplied by the wave washer, and the cranks tightened down onto that to a specified torque. I suppose you can adjust pre-load by adding washers.
Not right either or you weren't clear. There is no 'I suppose'. All BB30 cranks have preload. Many falsely believe preload is pre-determined. It shouldn't be. The BB may have come from the factory less than ideal. In fact a good chance it was. Majority of BB30 cranks have wave washers for preload but it is the spacing of the wave washer that determines where it is in its compression/force relative to deflection. The rest of BB30 cranks are mechanical preload which have adjustable preload by way of an expanding collar . Preload is one of the most important facets of crank set up influencing bearing durability and noise and a common problem why bearings can wear out prematurely and/or make noise.