Chain Stretch ?

echowitch

I am getting a slightly lurching/slipping sensation whilst riding at the moment every now and then. I suspect it is chain stretch but my LBS said it was ok (although another said the opposite a few weeks before hand.)

Is it time to replace my chain and cassette ? Or is something else the culprit ?

Chunkers1980

Chain stretch can be measured - I'd suggest you start there.

brucie45

It sounds like your chain is stretched but without looking it's hard for anyone to say for sure. As chunkers says, chains can be measured. Take a look at Seldon Brown on the link.

http://sheldonbrown.com/chains.html

97th choice

Get a chain checking tool, inexpensive and saves a new cassette and rings

The Rookie

To clarify, chains don't stretch as such, the joins wear and the accumulated 'slop' means they end up being longer than they should.....

97th choice

Are you Mr Logic from Viz?

cooldad

Nope he's just an annoying, pedantic know it all.

Annoyingly though, he is quite correct.

And annoying.

Chunkers1980

Not really. They don't end up being longer end to end. They are measured 'longer' with a chain checker due to the slop in the rollers and pins, not the outer plates getting longer through stretch.

cooldad

They do end up a bit longer. The wear is inside the rollers, so each pin is fractionally further along than before.

njee20

More than fractional - hold worn and new side by side, there's a big difference on the whole length.

Not really. They don't end up being longer end to end. They are measured 'longer' with a chain checker due to the slop in the rollers and pins, not the outer plates getting longer through stretch.

That's exactly what the Rookie said, but as per CD they do get phyiscally longer under their own weight, but you're right it's not plastic deformation of the side plates.

cooldad

njee20 wrote:

More than fractional - hold worn and new side by side, there's a big difference on the whole length.

Each link is fractionally longer - over a hundred odd the cumulative difference is significant.

Bloody pedantic pedants.

drlodge

Chains stretch, they get longer. Chain component parts do not stretch, they wear.

Chunkers1980

Blooming heck drlodge - that's concise and exactly to the point.

One thing to add - they only get longer when under tension or gravity (dangling). Under compression or pushed together on a table say, they'd actually be shorter.

bigmitch41

Take your chain and starting from a pinhole, measure off 12 inches of the chain. The 12 inches should hit the 12th link’s first pinhole, If it goes over by 1/16” past the mark, you’ve got to buy a new chain. If it is 1/8” past the mark, you will need to buy a new chain & cassette.

drlodge

Chunkers1980 wrote:

One thing to add - they only get longer when under tension or gravity (dangling). Under compression or pushed together on a table say, they'd actually be shorter.

Or if put in its side and curved, it will be more curved