Do I need a new cassette and/or chain ?

For discussions about bikes and equipment.
mnichols
Posts: 1465
Joined: 22 Apr 2013, 4:29pm

Do I need a new cassette and/or chain ?

Post by mnichols »

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: 44454
Joined: 4 Jan 2012, 6:25pm

Re: Do I need a new cassette?

Post by Brucey »

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

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
gxaustin
Posts: 890
Joined: 23 Sep 2015, 12:07pm

Re: Do I need a new cassette?

Post by gxaustin »

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: 1465
Joined: 22 Apr 2013, 4:29pm

Re: Do I need a new cassette?

Post by mnichols »

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: 44454
Joined: 4 Jan 2012, 6:25pm

Re: Do I need a new cassette?

Post by Brucey »

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
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
mnichols
Posts: 1465
Joined: 22 Apr 2013, 4:29pm

Re: Do I need a new cassette?

Post by mnichols »

Thanks, cassettes are expensive
mnichols
Posts: 1465
Joined: 22 Apr 2013, 4:29pm

Re: Do I need a new cassette?

Post by mnichols »

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: 2234
Joined: 22 May 2011, 7:14pm

Re: Do I need a new cassette?

Post by gregoryoftours »

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: 16
Joined: 1 Apr 2018, 10:00am

Re: Do I need a new cassette?

Post by Salty Seadog »

It's worth nothing you cannot really tell the condition of a cassette by looking at it like a chainset.
Brucey
Posts: 44454
Joined: 4 Jan 2012, 6:25pm

Re: Do I need a new cassette?

Post by Brucey »

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
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Marcus Aurelius
Posts: 1903
Joined: 1 Feb 2018, 10:20am

Re: Do I need a new cassette?

Post by Marcus Aurelius »

You can’t teach an old cog new links. I would get a new cassette as well if I were you.
mnichols
Posts: 1465
Joined: 22 Apr 2013, 4:29pm

Re: Do I need a new cassette?

Post by mnichols »

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: 44454
Joined: 4 Jan 2012, 6:25pm

Re: Do I need a new cassette?

Post by Brucey »

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
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
mnichols
Posts: 1465
Joined: 22 Apr 2013, 4:29pm

Re: Do I need a new cassette?

Post by mnichols »

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: 16
Joined: 1 Apr 2018, 10:00am

Re: Do I need a new cassette?

Post by Salty Seadog »

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