bicyclepost

Hello, I'm a complete newbie to single speed and fixed gear bikes. I recently got a fixie with a flip-flop hub and have been riding single speed with the freewheel for the past couple weeks. Today I flipped it around to fixed for the first time and it's quite noisy. The freewheel side was a perfectly quiet, smooth ride. I don't know if this is normal for fixed gears but it's pretty annoying because it sounds like there's something wrong. I tried different chain tensions but there was no difference. To my untrained eye, the chainline appears to be straight, but maybe slightly off. What else could be causing this? I also have two videos:

aggiegrads

I would check the rear hub bearings, cones, and races. I don’t think that there is anything wrong with chainline, chain, or gears.

Also check that there are no loose spokes.

Mikefule

If it doesn't make that noise in single speed, but does in fixed, then it's something at the back end. So that means not the chainring, and the chain alone is not the issue.

It's not the chain line, and the chain looks well lubricated.

I wonder, is your chain the right width for your fixed cog? If it is a size too narrow (say 3/16 instead of 1/4) that may be the issue.

Speedway2

I'm with Mikefule. I think the chain is not seating properly with the teeth of the fixed cog. It's (chain) probably been mated to the freewheel over the miles.
How old is the bike?

bicyclepost

From the research I did I thought that may be the issue. Perhaps the fixed cog is not the same size as the freewheel cog. How would I figure this out? Visually the chain appears to sit over the cog teeth fine but I'll flip it back to the freewheel side to see how it compares. I bought the bike used and have only ridden it myself for 2 or 3 weeks but the guy I bought it from built it himself from a road bike frame and I don't think it was used much. The chain appears to be brand new but the cogs look like they have some more wear on them. The fixed cog has fairly square teeth though.

y0x8

Fixed Gear is a completely noise-free operation. You can only hear one breath and a heartbeat.

jay4usc

sounds like you have Cheetos in your cog

y0x8

Rinse in a closed polyethylene bottle with gasoline or kerosene twice, dry. Lubricate with bike chain silicone lubricant. Clear the stars.

Rolla

If that's the case, the new chain might just need to be ridden a bit so it stretches to accommodate the teeth. Go climb hills.

Also, go ahead and measure your chainline. You might need to mount the chainring on the inside of the spider arms.

indigowarpz

I'm with Rolla here.
Is it possible that you just put a new chain on a cog/ring you've been riding already? The chain will need to wear in to fit the worn (even if only a little bit) teeth. In bikes with gears, you generally change your cassette when you change your chain so everything wears evenly. That way your chain isn't wearing out your cassette, or your cassette isn't wearing out your chain.

Best of luck

y0x8

Make sure everything is clean first. And only then carefully measure and examine the wear of all components. As an option: throw all this household into the trash and buy a new one.

TejanoTrackie 

Maybe the chain is too tight ?

FiftySix

That right there is likely the culprit. I can see those squared off teeth in the photo on the fixed cog.

FiftySix

Right. Never meant to imply that teeth did square off from wear.

But, that square tooth sprocket sure doesn't mesh well with that particular chain in the first post.

Rolla

Thanks - I re-read your post and deleted mine just before you posted this.

Yeah, I don't know if it has anything to do with the square aspect, but something's up with the chain/cog/chainring interface.

bmwjoe

I believe it is a new chain being used with a worn cog. I did this once and the noise was incredible! It was worse when under power. I only rode a couple hundred yards and turned around to put the old chain back on. Install a new rear cog and you should be quiet.

Altimis

Sources of sound can be many many thing.

-Your pedals bearing loose, its crazy but its true for me, try remove pedals and spin it, for me its gone. So I end up buy quality pedals to replace it.
-Too tight chain
-New chain (most new chain need some sitting before its quiet down)
-Out of chainline, freewheel and fixed flip-flop often not have the same chainline, you may get fine line freewheel, when filpped to fixed, you are out.

Scrodzilla

It's completely insane that so much over-thinking is done over such simple machines.

Colorado Kid

I had the same problem with my Fixed Gear. I've tried everything. What made it run better is some good lube. I'm using Finish Line right now and that seems work fine.

the sci guy 

sometimes a 1/8 chain rattling around on a 3/32 cog makes that noise

y0x8

Absolutely agree! The fixed mechanism is absolutely silent. There are times when it seems that the bike disappears under you and you run fast, fast, as if in sneakers.

TugaDude

I love that pic! How nice to not have to worry about aesthetics. Bar tape wouldn't matter, components needn't match. Awesome!
On a serious note, in the rare event I am biking near pedestrians I always have to announce my presence. If I don't, they never hear the bike coming and are startled as I pass by.

rustystrings61 

Nice to finally see the Emperors' new bike on the road!

sixty2strat

Experienced the exact same thing. The noise was unreal. Replaced with dura ace and its buttery quiet.