"clicking" feeling when installing cassette on hub
I have a 10 speed cassette that I've been using. Lately I've felt it just doesn't shift very well when it gets to the smaller cogs. I decided to try a thinner spacer for the cassette. I run November Rail 52's with a White Industries hub. What I noticed with the thinner spacer is that I don't get that typical 'click' feeling I was getting with just a slightly thicker spacer. Does that mean the spacer isn't a good fit? It seems to shift better, but I'm not sure I want to run with the thinner spacer if it isn't installed all the way. It seemed a little 'mushier' when putting it on with the thinner spacer.
it means the spacer is not thick enough to allow contact between the cassette retaining nut and the knurled side of the smallest cog.
Clean up or replace the shifting cables and or housings to the rear derailleur to fix the original shifting problems going to the smaller cogs.
There is less spring tension at that position and friction free cables make it easier for the derailleur to move to the outside.
ps. re-adjust the derailleur screws before you ride.