How do you know when a single-speed chain needs replacing?

chris-suffolk

Well-Known Member
Same as any chain, use chain checker and replace accordingly. Pretty much standard to replace at or before 0.75 on the gauge
 

ColinJ

Puzzle game developer
How do you know when a single-speed chain needs replacing? Will there be an adverse effect on performance?
If the bike has a chain tensioner then worn chains need much more work from it. My bike gets noisier as the chain wears. It is nice and quiet with a new chain, when the tensioner barely touches the chain...

584108


This is what it looks like with a slacker worn chain...

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It doesn't really make it harder to ride though!

If you didn't take up enough slack then there would be more chance of the chain coming off.

PS Yes, there ARE 2 sprockets but the smaller one is only there for the lockring to bite against! I used to tighten the ring directly against a stack of spacers but it came loose on a couple of rides.
 
OP
Chris S

Chris S

Legendary Member
Location
Sparkhill
If the bike has a chain tensioner then worn chains need much more work from it. My bike gets noisier as the chain wears. It is nice and quiet with a new chain, when the tensioner barely touches the chain...

View attachment 584108

This is what it looks like with a slacker worn chain...

View attachment 584109

It doesn't really make it harder to ride though!

If you didn't take up enough slack then there would be more chance of the chain coming off.

PS Yes, there ARE 2 sprockets but the smaller one is only there for the lockring to bite against! I used to tighten the ring directly against a stack of spacers but it came loose on a couple of rides.
Thanks. My bike has a 3-speed hub gear but a worn chain would have the same consequences. I haven't got a gauge so I'll just replace the chain when it starts coming off.
 

swee'pea99

Legendary Member
You don't need a proper gauge, all you need is a ruler. (And a decent pair of eyes.)

Get a 12" ruler, and line up the 0 point exactly over a rivet. Now look at the 12" point on the ruler. If your chain is brand new, that will also be exactly over a rivet. As your chain wears, the 12" mark will start being a little bit past the rivet, then a bit more, then a bit more.

1618506549012.png


Rule of thumb: if it's more than 1/16th" out, you need a new chain. (So the one in the pic would be for the knackers.)
 

chris-suffolk

Well-Known Member
Thanks. My bike has a 3-speed hub gear but a worn chain would have the same consequences. I haven't got a gauge so I'll just replace the chain when it starts coming off.
A chain gauge is cheap compared to chains (and sprockets). If it means you change the chain at the right time then you maximise the chain life, and don't change anything un-necessarily. Run the chain for too long (uncluding it starting to come off IMO), and it's likely to be new sprocket time too.
 

yello

Legendary Member
Location
France
For me it's a chain gauge, noise and/or feel. The gauge should have the final say but worn chains can sound and feel (a notchiness, if that's a word) past their best. A gauge is a obviously a preemptive test too; a noisy chain being already gone/on it's way out.
 

rogerzilla

Legendary Member
Allow a clean chain to hang freely (yes, you might need to clean it then throw it away).

12 full links measure up to 12 1/16", refit.

12 full links measure between 12 1/16" and 12 1/8", you can re-use it but it is now killing the sprocket.

12 full links measure over 12 1/8", you should replace the chain and sprocket, as a new chain will not run smoothly on the worn sprocket.

If you are happy to replace the sprocket each time, you can more or less run them both into the ground. It takes a lot to wear out the (expensive) chainring.
 

T4tomo

Guru
If you are happy to replace the sprocket each time, you can more or less run them both into the ground. It takes a lot to wear out the (expensive) chainring.
This is the pragmatic option given you are replacing a relatively cheap sprocket and not an expensive 11spd cassette. That was pretty much my approach on the brompton (3spd), which is effective a single speed for the purpose of this discussion.
 

silva

Senior Member
Location
Belgium
I replace chain and rear cog when the latters teeth appear to be close to breaking.
At the moment I think I'll will continue until this actually occurs - I have new chain and new and worn spare cogs with me so that I can fix it till back home or immediately, depending on along the road - situation.
In the future I plan to flip the rear cog more frequently, and not only in its last lifecycle part.
 
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