I was riding my fixed gear the other day when the front wheel slid out on a right turn and the bike and I went down on our right side. The rest of the ride home I felt what I believe was the chain slipping on either the cog or the chain-ring every so often.
I assumed the slam to the pavement loosened the rear wheel, giving the chain too much slack and causing the slipping on either the cog or chain-ring. I pulled the wheel, degreased/lubed the chain and popped it back on, ensuring the chain had sufficient tension. I took a ride to make sure everything was okay, though I could hear the chain rubbing at one point during each rotation of the wheel.
Upon closer inspection I noticed that there was normal chain tension at one part of the rotation and very tight tension at another point, which was when the rubbing was occurring. It was like the cog or chain-ring was oval shaped.
I donít think this is a chain problem, as I have not had any issues with the chain before. Can you provide any ideas as to what might be causing this?
Thanks in advance for your help!