Do I need a new cassette and/or chain ?

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mnichols
Posts: 1149
Joined: 22 Apr 2013, 4:29pm

Do I need a new cassette and/or chain ?

Postby mnichols » 12 Aug 2018, 5:38pm

Just doing a few bike checks ahead of an upcoming tour ( 8 days/800 miles along the south coast of France) and my chain checker drops into the links on the 0.75 and 1.00 test, so I'm going to replace the chain, but do I need a new cassette?

LBS always says that if it gets to 1.00 then it's best to replace the cassette, but is that right? Seems a bit wasteful, is there a better test?

Brucey
Posts: 29939
Joined: 4 Jan 2012, 6:25pm

Re: Do I need a new cassette?

Postby Brucey » 12 Aug 2018, 6:00pm

best test is to fit a new chain and try it. If the cassette is no good the chain will skip under load.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

gxaustin
Posts: 297
Joined: 23 Sep 2015, 12:07pm

Re: Do I need a new cassette?

Postby gxaustin » 12 Aug 2018, 6:30pm

I used to run my chains to 0.1 and never wore out a cassette after several chains. None of the teeth were hooked. I finally changed it when I decided I needed lower gearing. I'd try it first as Brucey says. I tend to change chains rather earlier now because I use dearer cassettes :lol:

mnichols
Posts: 1149
Joined: 22 Apr 2013, 4:29pm

Re: Do I need a new cassette?

Postby mnichols » 12 Aug 2018, 8:19pm

Brucey wrote:best test is to fit a new chain and try it. If the cassette is no good the chain will skip under load.

cheers


Does that mean it would be skipping under load now with the existing chain if it needed replacing?

Brucey
Posts: 29939
Joined: 4 Jan 2012, 6:25pm

Re: Do I need a new cassette?

Postby Brucey » 12 Aug 2018, 8:40pm

mnichols wrote:
Brucey wrote:best test is to fit a new chain and try it. If the cassette is no good the chain will skip under load.

cheers

Does that mean it would be skipping under load now with the existing chain if it needed replacing?


No; worn chains carry on running on worn cogs for a long time before they give trouble, (but this approach knackers the sprockets and chainrings, which are expensive).

New chains skip on sprockets that are too worn, but if you change your chain before a certain point, this is avoided, and you have a transmission that runs smoothly and doesn't cost a fortune to keep in fine fettle.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

mnichols
Posts: 1149
Joined: 22 Apr 2013, 4:29pm

Re: Do I need a new cassette?

Postby mnichols » 12 Aug 2018, 9:33pm

Thanks, cassettes are expensive

mnichols
Posts: 1149
Joined: 22 Apr 2013, 4:29pm

Re: Do I need a new cassette?

Postby mnichols » 12 Aug 2018, 9:44pm

What chain would you recommend to go with a 10 speed 105 shimano setup?

Although it has this chainset https://www.spacycles.co.uk/m2b0s109p3534/SPA-CYCLES-RD-2-Triple-Chainset-with-Zicral-Rings

gregoryoftours
Posts: 751
Joined: 22 May 2011, 7:14pm

Re: Do I need a new cassette?

Postby gregoryoftours » 12 Aug 2018, 11:26pm

If you favour certain gears a lot you can get skipping with a new chain on a used cassette even when the old chain was only just due for replacement. As for replacement I'd go for Shimano or a mid range kmc chain. I don't have great experience with SRAM.

Salty Seadog
Posts: 10
Joined: 1 Apr 2018, 10:00am

Re: Do I need a new cassette?

Postby Salty Seadog » 13 Aug 2018, 7:46am

It's worth nothing you cannot really tell the condition of a cassette by looking at it like a chainset.

Brucey
Posts: 29939
Joined: 4 Jan 2012, 6:25pm

Re: Do I need a new cassette?

Postby Brucey » 13 Aug 2018, 10:32am

Salty Seadog wrote:It's worth nothing you cannot really tell the condition of a cassette by looking at it like a chainset.


yup. The difference between a tooth shape that promotes skipping and one that does not is sometimes only a few microns.

FWIW one of my chums recently fitted a SRAM 10s chain (of which he has used many before without issue) and the hollow rivets were clearly scuffing neighbouring sprockets and marking them up. The chain measured ~6.1mm width, i.e. it was part-way between the usual size for 10s and 9s. KMC replacement is the correct width.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Marcus Aurelius
Posts: 124
Joined: 1 Feb 2018, 10:20am

Re: Do I need a new cassette?

Postby Marcus Aurelius » 13 Aug 2018, 1:19pm

You can’t teach an old cog new links. I would get a new cassette as well if I were you.

mnichols
Posts: 1149
Joined: 22 Apr 2013, 4:29pm

Re: Do I need a new cassette?

Postby mnichols » 13 Aug 2018, 5:16pm

I don't want to replace the cassette every time I replace the chain. Is there a rule of thumb that says after every n chains you need a cassette?

If I try the chain first on my Saturday ride and it skips under load will this damage the chain and then I need another new chain plus a cassette?

I've order a chain which I'll fit tomorrow, I'll ride around the block, but my next ride on that bike is Saturday and is around 110 miles with 6000 feet of climbing

I use a Shimano 105 12/30 on the back and they are £41 from Wiggle

Brucey
Posts: 29939
Joined: 4 Jan 2012, 6:25pm

Re: Do I need a new cassette?

Postby Brucey » 13 Aug 2018, 5:31pm

mnichols wrote:I don't want to replace the cassette every time I replace the chain. Is there a rule of thumb that says after every n chains you need a cassette?

If I try the chain first on my Saturday ride and it skips under load will this damage the chain and then I need another new chain plus a cassette?

I've order a chain which I'll fit tomorrow, I'll ride around the block, but my next ride on that bike is Saturday and is around 110 miles with 6000 feet of climbing

I use a Shimano 105 12/30 on the back and they are £41 from Wiggle


You won't ever stop the cassette from wearing completely, but provided the chain isn't ever too worn, the tooth profile normally remains compatible with a new chain. The exact point at which you last get the chance to change your chain varies from bike to bike and rider to rider, but it is normally in the range of 0.5% to 0.75% wear.

If the chain skips under load, this is normally apparent very quickly. You should test ride the bike before comitting to a long ride; a few skips is unlikely to break anything but an all day ride like that is a different matter. If it skips it will usually skip on the most used sprockets.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

mnichols
Posts: 1149
Joined: 22 Apr 2013, 4:29pm

Re: Do I need a new cassette?

Postby mnichols » 13 Aug 2018, 7:21pm

Thanks I get through a lot of chains and cassettes. I seem to wear them out quickly. I'm doing about 8,000 miles a year - I'm not sure how long they are supposed to last

Salty Seadog
Posts: 10
Joined: 1 Apr 2018, 10:00am

Re: Do I need a new cassette?

Postby Salty Seadog » 13 Aug 2018, 7:33pm

There is an often quoted rule of thumb that is 3 chains to 1 cassette.