UberIM

Doc,

I have a 2009 Fuji Touring bike converted to a single speed. I use SPD pedals and it is I think a Mavic Mtn Bike crank set
It has probably greater than 3000 miles on it - used through all 4 seasons here in Maine.
Recently I noticed the following:
Intermittently I get a clicking, almost gritty feeling when pedaling-feels perhaps more on the right than the left. It seems most obvious when I am "trying to catch up my RPMs-i.e. if I normally ride at 80-90 rpm on a flat surface when I go down hill it seems to be worse (maybe) when the bike speeds up and I have to go 100 rpm, say. But it is intermittent and not always in this situation and also other situations.

I brought it into the LBS and an experienced mechanic looked at it. He said the BB was fine (I thought that it might be wearing out and this was the first sign before it got loose?). He said no. The chain was cleaned and placed back on the chain ring and rear sprocket and the the tire pulled back to tension it.......The mechanic noticed that my front chain ring was not perfectly round and the chain at one point gets tighter and rises in that arc of the pedal stroke........but he didn't think of that........

I feel a little Shakespearean: out damn spot.......I could replace the chain and chain ring and sprocket in the rear and even the BB and still have the problem. When the mechanic test rode the bike he couldn't appreciate the clicking..........

Any thoughts for this obsessive nut case high maintenance commuter (other than you are glad you don't work in my LBS ? :-) )

Thanks