How/why does shifting performance decrease when a chain needs to be lubed? I'm not at all doubting the effect just trying to understand it... If the point of lube is keep the links lubed and free of rust then the rest of its application is really spurious? And by link I just mean the two little moving barrels in the link. How do lubed, rust free links effect shifting performance? Pardon the noobness of the question, I can see how a dry chain could be a problem in other ways, but shifting? And both front and rear shifting? Thanks.