Chain Stretch - Good News...

[Bodhbh]

Cheers, 3000 quite mucky miles on the chain atm, be interested to see what the state of play is!

 

[Chris James]

Incidentally, since most rules don't have markings beyond the 12th inch it is often easier to measure 10 inches as suggested by Chris Juden of the CTC.

To be honest, using a chain check is easier though, if you already have one. It is effectively a go / no gauge. You position one end against a chain roller and see if you can insert the other end completely into your chain. If the chain isn't worn then the chain checker will foul on a roller and not allow itself to be totally inserted. If it slides in then it is worn. If it slides in on the 0.75% setting but not n the 1% setting then it is partly worn and due for a change but hopefully your cassette will be okay. If both go in easily then your drive chain in probably goosed.

 

[PrettyboyTim]

I changed my chain about a year ago. I think I do about 3500 miles / year, and I'm not very dilligent at chain cleaning. I tend to clean it once it's really mucky.

Last week I cleaned my chain and measured it. It wasn't quite up to the 12" 1/16th mark so I figure it's good to go for a little longer.

It's a 7 speed cassette, but it might be a 8 speed chain.

I do change gears a lot; I've had to change my gear cable more than I've change my chain...

 

[Randochap]

Look and learn

From Sheldon...

The standard way to measure chain wear is with a ruler or steel tape measure. This can be done without removing the chain from the bicycle. The normal technique is to measure a one-foot length, placing an inch mark of the ruler exactly in the middle of one rivet, then looking at the corresponding rivet 12 complete links away. On a new, unworn chain, this rivet will also line up exactly with an inch mark. With a worn chain, the rivet will be past the inch mark.

This gives a direct measurement of the wear to the chain, and an indirect measurement of the wear to the sprockets:

• If the rivet is less than 1/16" past the mark, all is well.
• If the rivet is 1/16" past the mark, you should replace the chain, but the sprockets are probably undamaged.
• If the rivet is 1/8" past the mark, you have left it too long, and the sprockets (at least the favorite ones) will be too badly worn. If you replace a chain at the 1/8" point, without replacing the sprockets, it may run OK and not skip, but the worn sprockets will cause the new chain to wear much faster than it should, until it catches up with the wear state of the sprockets.
• If the rivet is past the 1/8" mark, a new chain will almost certainly skip on the worn sprockets, especially the smaller ones

Sheldon -- BHS -- was right. That's "the standard way" we all did it for years. But, a chain checker will save you from reading all the above and bujjering around with tape measures and -- if you're like me -- trying to find your magnifying glass.

Watch the demonstration video at this link and see how it's done.