What is that grinding noise on my fixed gear?

[ShawnoftheDread]

@OneEighth 146860 wrote:

Not when you are running big honking studded tires and riding in snow. But yes, otherwise the magic number is 16.

Some people don’t go out in snow because it messes with their chi or something.

[EasyRider]

@americancyclo 146825 wrote:

but when I stand up on the pedals, it gets loud and grindy.

I agree with others about chain tension. My guess is that the frame is flexing a tiny bit when you stand on the pedals, increasing the chain tension. To account for it, I’d just need to move the rear wheel forward in the dropout a tiny bit, taking care to make sure it is centered. Did you remove the wheel when you replaced the chain? I’d also check to see if the chainring bolts needed a quarter turn. Your rear cog doesn’t look worn out to me.

Back when my commute was shorter and flatter, as my fixed gear’s chain would wear, I’d bump the wheel back once or twice by a fraction of an inch to maintain chain tension, before finally replacing it. Sounds like you maybe just need to do the opposite, since it’s a new chain.

[americancyclo]

@EasyRider 146862 wrote:

I agree with others about chain tension. My guess is that the frame is flexing a tiny bit when you stand on the pedals, increasing the chain tension. To account for it, I’d just need to move the rear wheel forward in the dropout a tiny bit, taking care to make sure it is centered. Did you remove the wheel when you replaced the chain? I’d also check to see if the chainring bolts needed a quarter turn. Your rear cog doesn’t look worn out to me.

Back when my commute was shorter and flatter, as my fixed gear’s chain would wear, I’d bump the wheel back once or twice by a fraction of an inch to maintain chain tension, before finally replacing it. Sounds like you maybe just need to do the opposite, since it’s a new chain.

I had to re position the wheel when I put the new chain on. The old one was stretched to at least 1.0 on the chain checker. Bike was quiet before the new chain and nothing else changed, so it’s gotta be the tension, cog, or chain ring. I made sure to tighten the chain ring bolts before i put on the new chain.

[EasyRider]

This got me thinking about chain wear and fixed gear. It’s been a few years since I rode a fixed gear, but as I said, my memory is that I would periodically bump the wheel back to maintain chain tension. But thinking about it, my understanding of chain wear/stretch is too vague to know if chain wear would actually result in less chain tension on a fixed gear bike that could remedied by moving the wheel back. In other words, perhaps I’m full of it?

Still, it sounds like your chain is just a hair too tight.

[americancyclo]

sounds like this:
[video=youtube_share;HzCVEhb1J4k]https://youtu.be/HzCVEhb1J4k[/video]

[ShawnoftheDread]

Note to self: negotiate cost of neglected maintenance when purchasing bikes from Subby.

Sent from my iPhone using Tapatalk

[huskerdont]

Mostly I hear wind noise (I have been to too many punk and metal shows though), but that chain looks bouncy, not too tight. So this chump doubles down on the cog.

[bentbike33]

@huskerdont 146875 wrote:

Mostly I hear wind noise (I have been to too many punk and metal shows though), but that chain looks bouncy, not too tight. So this chump doubles down on the cog.

Speaking as a chump who rides only bikes with shifters, why wouldn’t you replace the cog and chainring on a SS/fixie when you replaced the chain, especially if the chain has measurably stretched? You might be able to get away with a chain-only change if you are derailleured up because the chain wears over multiple cogs and chainrings, which is obviously not the case on SS/fixie set-ups. A new chain on a cassette that should have been changed makes some ugly noises too.

[americancyclo]

@OneEighth 146846 wrote:

I’ve had that happen before when I changed the chain but not the cog or chainring. If you’ve got 1/4 to 1/2 inch play in the chain at the tightest point, then it is probably your cog and/or chainring.

Does that mean you change all three at once?

[EasyRider]

I would think that if it’s a worn cog not meshing properly with a new chain, it’d be noisy all the time, and not just when you are out of the saddle, but I second huskerdont’s advice. Even if the free solutions (easing up on the chain tension, checking wheel alignment) solve the problem, buy a new cog. A brand-new cog is a delight to hold.

[TwoWheelsDC]

@bentbike33 146880 wrote:

Speaking as a chump who rides only bikes with shifters, why wouldn’t you replace the cog and chainring on a SS/fixie when you replaced the chain, especially if the chain has measurably stretched? You might be able to get away with a chain-only change if you are derailleured up because the chain wears over multiple cogs and chainrings, which is obviously not the case on SS/fixie set-ups. A new chain on a cassette that should have been changed makes some ugly noises too.

Fixed gear drivetrains are generally pretty robust (no shifting ramps and what not, and 1/8″ is pretty hefty) so I can’t imagine needing a sprocket change for every chain change. Since no shifting is involved, you can generally get longer useful life out of them even if they are worn, assuming you can deal with increased noise.

[honestmachinery]

@TwoWheelsDC 146884 wrote:

Fixed gear drivetrains are generally pretty robust (no shifting ramps and what not, and 1/8″ is pretty hefty) so I can’t imagine needing a sprocket change for every chain change. Since no shifting is involved, you can generally get longer useful life out of them even if they are worn, assuming you can deal with increased noise.

1/8 inch cogs and chainwheels should last a long time with timely chain replacement. I changed my chain before it was indicated by chain length, and it was definitely noisier. As long as the chain isn’t binding at any point through a complete revolution, or hanging on the teeth, I wouldn’t worry.

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[americancyclo]

Going to try a new cog, and considering a new chainring as well. Will update when i get it installed.

[huskerdont]

@bentbike33 146880 wrote:

Speaking as a chump who rides only bikes with shifters, why wouldn’t you replace the cog and chainring on a SS/fixie when you replaced the chain, especially if the chain has measurably stretched? You might be able to get away with a chain-only change if you are derailleured up because the chain wears over multiple cogs and chainrings, which is obviously not the case on SS/fixie set-ups. A new chain on a cassette that should have been changed makes some ugly noises too.

Somehow missed this. The site doesn’t always show new posts in bold for me, but I tend to trust it like it does.

So, yeah, you might well change them all at once, if that’s the way you do things, and many people do. I tend to try the chain first to see if I can get away with it, then move to the cog, then go to the chain ring as a last resort. Cheap maybe, but if you replace your chain in time, before it wears the other parts down, it works, just as it might work on a bike with gears.

I just discovered that my 9-speed road bike suddenly has chain wear that shows on the wear indicator at 0.5 but not at 0.75, so I’m going to get a new chain first and see what happens before I change the cassette. I may end up needing a cassette too, and in the past I probably would have replaced both at once, but since I have the wear indicator, I thought I’d give it a try. I think it’s just a way of doing things and isn’t either right or wrong. I don’t change chain rings on a shifty bike unless I’ve hurt myself at least once when the chain comes off.

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