Rat a Tat noises coming from my bottom bracket area. Please help! I recently got my single speed frame and forks powder coated and at the same time had a number of parts replaced - bottom bracket, chain ring, chain and freewheel cassette.  Really please with everything I took it for a ride and almost immediately heard a rat a tat noise coming from the bottom bracket.  Can be felt through the pedals and saddle.  The noise came and went so I returned it to the bike shop who checked and regreased everything.  They put their pedals on and stated the noise disappeared.  I've taken it out again and happily found the noise had gone until 3 miles in when I freewheeled for a bit and when I started pedalling the noise was back with a vengeance.  The volume varies and comes and goes but only ever appears after I stop pedalling for a bit and restart.  I'm convinced it is not my pedals as never been an issue and the noise just doesn't fit.

Any ideas before I go back to the shop to protest?
I think it's the single speed freewheel.

I've just been through almost exactly the same thing with a brand new Cross Check SS. From day one I had a fast, regular clicking when pedalling, about 4-5 noises per pedal revolution. I could sometimes get it to calm down by pedalling backwards a bit. I was convinced it was the bottom bracket too, until I got the whole crank section rebuilt and it didn't help.

Eventually found some forum posts that described a problem with some SS freewheels, e.g.:


http://www.bikeforums.net/singlespeed-fixed-gear/436916-freewheel-noise-while-pedaling.html
http://forums.roadbikereview.com/general-cycling-discussion/whats-knocking-my-single-speed-211923.html


My bike came with a 17 tooth Shimano freewheel. I got a White Industries freewheel instead and it's been a dream (although the normal ratchet noise when freewheeling is louder now).

Could you try a fixed cog or another rear wheel to eliminate the freewheel?