Replacing chain and cassette

cm59 · Post by **cm59** » 07 May 2009 10:20

Hi just wondering when anybody replaces their chain and cassette do they just go on a mileage? Just wondering cuz Ive got some long rides coming up and i dont want my chain to break half way round do they give warning when Theyre on the way out or just break?

RichK · Post by **RichK** » 07 May 2009 10:44

Unless I have another reason to then I replace the chain when it's worn to 1% - have a small tool for checking just that - buy the new one to be ready when it reaches the 0.75% worn level.

Philip Whiteman · Post by **Philip Whiteman** » 07 May 2009 10:46

I replace the chain when it is worn rather than mileage. Its wear depends upon the time of year and road conditions, quality of chain, wear on your chain rings, etc.

There is a simple way of measuring chain wear, using a gauge:

http://www.chainreactioncycles.com/Mode ... elID=10219

In terms of changing the rear cassette, this depends upon how old it is. Quite often you have to replace the cassette along with the chain unless the chain is replaced fairly early and the cassette is not that old.

cm59 · Post by **cm59** » 07 May 2009 10:56

Ok cheers ill have to get one of those tools whats the average time in your experience or is it always different

Philip Whiteman · Post by **Philip Whiteman** » 07 May 2009 11:29

cm59 wrote:Ok cheers ill have to get one of those tools whats the average time in your experience or is it always different

Alister at Birmingham City Cycles sells them.

If you replace the chain and cassette, you can do it yourself with the appropriate tools but it is a fag, so you could just take the bike to the shop in any case.

Post by **CakeStop** » 07 May 2009 12:53

I use mileage as a guide but measure with a steel rule to check when I think it's about time to change the chain. You measure a 12" length (24 links) pin to pin with the chain under a little tension. The chain needs changing when the far pin is 1/16" past the mark - you can carry on until 1/8" but then you'll need to change the cassette too. I have been meaning to get a chain gauge but never got round to it.

I rotate chains to extend the life of the cassette. It doesn't always quite work out but my ideal routine is: starting with 2 new chains, every 1000 miles I swap the chains leaving the old one soaking in white spirits. When both chains have done 3 turns I'll thiink about replacing the cassette as well as both chains.

So I aim for 3000 miles per chain and 6000 miles per cassette but at that stage on my old bike I just changed to a 3rd chain - the current chain has done 3000 and the cassette 9000 and it's all just starting to get a bit gnarly.

YMMV depending on how clean you keep your chain.

Andy M · Post by **Andy M** » 07 May 2009 15:28

If in doubt and you've got long rides coming up why not change it anyway ?
I got my last chain from Dotbike.com--it was much cheaper than the nearest bike shop and it came within one day.
I've only just changed mine, and even though my cassette is old the gears work fine.

cm59 · Post by **cm59** » 07 May 2009 16:16

Ok cheers for all the help Ive checked it with a ruler and it seems fine Ive looked on the net and it looks like i can manage changing it which type do i need Ive got a shimano eight speed just any chain then reduce links to match length with old one?

Philip Whiteman · Post by **Philip Whiteman** » 07 May 2009 16:27

cm59 wrote:Ok cheers for all the help Ive checked it with a ruler and it seems fine Ive looked on the net and it looks like i can manage changing it which type do i need Ive got a shimano eight speed just any chain then reduce links to match length with old one?

I am assuming that an eight speed bike needs an eight speed chain. In terms of length, that is an irrelevance, whether it is 10,9 or even 5 speed.

I recently used the calculator as discussed in another thread to calculate my chain length. Alternatively, just measure the old one against the new one.

http://www.beaconrcc.org.uk/message_boa ... php?t=2259

Post by **CakeStop** » 07 May 2009 17:06

You can use any Shimano compatible 8 spd chain, I used to prefer SRAM but I've recently been converted to KMC.

If the current chain is Shimano original it'll be fixed together with a joining pin and you'll need a chain tool to break it. KMC and SRAM chains come with a joining link which is better (IMHO) than faffing with a joining pin (although you can use KMC joining links on shimano chains). In any case you'll need a chain tool to remove a few links from the new chain to take it down to size.

It's easy, even I can do it.