I got my fixed gear out of storage, where it's been for four years. Everything seems fine, except when I ride with anything more than light force on the pedals, I get a kind of br-r-r-r-r-r noise. It definitely corresponds to the degree of force I'm pedaling with (louder during the part of the stroke where I'm pushing hardest).

I vaguely remember running into this before, and the problem was having the chain too tight. But I've set it to have enough slack to be able to lift it up about an inch. The chain is lubed and in good shape. It really doesn't sound like bb noise.

Any other ideas? Thanks.

Replace the chain. For $15 it's a quick fix.

Sounds like links might have developed some rust or stiffness while in storage even if it looks in good shape and well lubed.

could be the chain, but I think if it was you would get the noise pressure or no pressure, Sounds more like a dry or worn out bottom bracket.

IME an over tight chain definitely makes more binding noise as pedaling forces increase. And you can feel the binding more as well.

OP. Remove the chain and see if all the links move freely and smoothly. With the chain off you can also spin the cranks to feel/listen to the BB.

Thanks, all. I replaced the chain and it reduced though didn't totally eliminate the noise. Maybe a little break-in will fix the rest.