I have a single speed bicycle I'm working on at the moment. It works fine under light pedaling and coasting, but becomes rough to pedal under load. I get a general "vibrating" kind of feeling in the bicycle when pedaling under load, as if something isn't meshing quite smoothly.
The problem began in earnest when I changed to a new crank set and put on a new chain. I went through and made sure there were no tight links. I opened the rear hub up today and found no problems there-- it appears brand new and has plenty of grease.
Would a wacky chainline cause this kind of a reaction or would that run rough all of the time? The roughness under load is driving me nuts. It runs fine on a flat or downhill, but the minute I have to tackle a hill and I apply force to it I get the problem.