Weird noise on fixed side after beach ride - disappears on freewheel?

[lorextreme]

Hey everyone, hoping someone can help me figure this out.

I took my flip-flop hub bike to the beach and when I got back I could feel the chain had picked up sand — that gritty feeling between the links. I did a proper clean, took the chain off, put it in a container with dish soap and water, shook it well, and there was definitely sand sitting at the bottom after, so the clean went fine.

After putting everything back together I switched to the fixed side and started getting this weird noise while pedaling. It would get louder and louder the faster I pedaled, like it was directly related to cadence. Tried everything — checked chain alignment, went through all the usual suspects — nothing fixed it.

On a whim I flipped the wheel to the freewheel side and the noise completely disappeared. Pedaling smooth and silent.

So yeah, fixie side makes noise that scales with pedaling speed, freewheel side is totally silent. Anyone know what could be going on?

 

[Sharky]

Is the number of teeth the same on both sides?
When tensioning the chain, is the wheel slightly more fore/aft than the freewheel and causing the chain to be very close to the chain stays?

 

[fossyant]

Potentially you've a worn chain and or sprocket and it's not meshing well. I had this when I'd been on an 'evens' sprocket for a number of months, then had a puncture and put the wheel back in. The chain had shifted along a tooth, and it sounded like a tractor. Fixed by moving the chain along one.

 

[lorextreme]

Is the number of teeth the same on both sides?
When tensioning the chain, is the wheel slightly more fore/aft than the freewheel and causing the chain to be very close to the chain stays?

The chain is fine cause it works perfectly with the other freewheel side. And before my ride it used to work perfectly and I haven't modified the chain at all, to clean it I just took off the master link.

 

[lorextreme]

Potentially you've a worn chain and or sprocket and it's not meshing well. I had this when I'd been on an 'evens' sprocket for a number of months, then had a puncture and put the wheel back in. The chain had shifted along a tooth, and it sounded like a tractor. Fixed by moving the chain along one.

Both sides have the same number of teeth. And the wheel position is the same on both sides since it's a flip-flop hub, I just flip the wheel around. So idk.

 

[midlife]

Is it like a squeaking / creaking noise ?

 

[Sharky]

I'm running out of ideas, but have you checked the cone lock nuts? Is the axle too tight or too loose? It could be that turning the wheel round, it tightens the cones too much?

You will probably have try a new fixed sprocket or try putting the freewheel onto the fixed side of the hub and see if the noise remains.

 

[midlife]

Swap it back to the fixed and leave the chain slightly slack. Sometimes the chain wheel is slightly eccentric and twice per revolution the chain can get very tight and make a noise. (The creak / squeak / cracking sound I mentioned above). Starting off slack stops any over tightening if the chain.

 

[Fastpedaller]

Has everything previously been ok with the setup on fixed? Has the freewheel been used frequently but the fixed used infrequently (therefore not worn as much as the teeth on the freewheel?)