Parson

Until today I have been running a 105 12-27 cassette on the wheel that came with my bike without any problems.

Today I installed an ultegra 11-28 on a power tap g3 wheel with 11 speed compatible hub. Now I can't shift into the 28 tooth cog. When I try, the lever won't budge. it feels like its already in the largest cog and there is no room to go further.

When installed the hub using the 10 speed adapter/spacer and the spacer supplied with cassette as instructed, the smallest cog overlapped the hub body slightly. I couldnt tell if the slots of the cog were fully set on the hub, but it seemed like they were overhanging slightly.

Thinking that there shouldnt be overhang, i removed the supplied cassette spacer and then tightened the lockring. The lockring tightened on the cassette and there is no looseness/play.

Is it okay for the smallest cog to overhang slightly? If so, maybe things will shift fine if i use the spacer. If not, i guess i have to adjust the rear deraileur?

Thanks for any suggestions.

catonec 

Adjust your limit screws.

If that doesnt help (I bet it will) you may have a physical limitation issue.

I use a short cage 9 speed chorus rear deraileur. its maximum cog capacity is 27. at 28 the cage and chain rub against the largest cog