I just replaced my 11-25 shimano 105 cassette with with a brand new 12-27. This bike was new about 700 miles ago.
Now, when pedaling in all gear combinations, there is a bumpy or rough feeling that was not there with the old cassette. It's not a clicking or creaking noise, just a feeling in the pedals and a slight low rumbling sound. I've carefully adjusted the derailleur chain tension, limit screws, and b-screw, and I am certain they are not rubbing on the chain.
Is it possible that this rough feeling is because of chain wear? I thought my chain would last a lot longer than 700 miles - I mostly ride on dry, clean roads, but do get caught in the rain every once in a while.
I used a ruler to measure the chain, based on Sheldon Brown's website, and I found about 1/16" of chain stretch. Also, when the chain is on the big chainring, I can pinch the chain in the middle and pull it off the chainring and make a 1/8" gap.
Should I replace this chain? Is there something else that could cause this rough feeling?