Changing cassette

[GlenBen]

Looking to change the cassette on my allez to one with smaller jumps. It has an 11-32 fitted at the moment, but I rarely use the 11 and very very rarely use above 24. (I live in a very flat area).

Its a suntour one fitted currently, looking to just swap to a hg50 shimano (12-25?). I was told in the lbs that the chain + cassette combo is whats causing it to be 'noisy' for lack of a better word. Is this likely to be the case? Its a kmc chain, x9 i think.

Also...this is the rear derailluer, will a smaller cassette be compatible with this?


Sorry to blurt out every question thats ever come into my head.

 

[Yellow Saddle]

Yes, you can fit a different cassette to that bike. You may have to shorten the chain a bit,depending on how much smaller the largest sprocket on the cassette will be.
You don't describe the noise, nor tell us when and how it occurs, so any advice in that vein will be guesswork.

I hope more questions come to mind, the world is a fascinating place.

 

[smokeysmoo]

There's a step by step guide HERE, also tells you the tools you'll need

It's a doddle of a job, with the right tools of course

 

[GlenBen]

Lovely, guess I shall get one ordered then.

The noise...I dont know how to describe it. Its constant when pedalling, under any pressure. Sounds a bit like when the limit screw isnt quite set right and it tries to jump cogs, but its all set up right. Its not awful, more of an annoyance.

The bikes done about 300 miles, think itll still need a new chain?

 

[Yellow Saddle]

That isn't many miles but the conventional wisdom is that you always replace the chain when you replace the cassette.

No Adrian, it is not. It is conventional myth that dictates that, not wisdom or reality. You've been here long enough to have seen the facts presented with back-up explanations.

A chain only has to be replaced when it is out of spec i.e. has elongated by more than 0.5%. Up to that point it does no damage to a cassette, new or otherwise.

 

[midlife]

Just out of curiosity if the op buys a Shimano HG casette will he need to buy an HG compatible chain or doesn't it work like that any more?

Shaun (from the 1970's)

 

[Yellow Saddle]

Conventional wisdom is conventional myth. Actual wisdom is something else.

I am saying you are perpetuating myth, not wisdom.

 

[Yellow Saddle]

That is why i used the phrase "conventional wisdom" so that the recipient might recognise it as such when the bike shop say it.

That's obscure. What is your actual advice to the OP?

 

[Yellow Saddle]

Hy

Just out of curiosity if the op buys a Shimano HG casette will he need to buy an HG compatible chain or doesn't it work like that any more?

Shaun (from the 1970's)

By definition all modern cassettes are Hyperglyde. This was a system that called for strategically placed ramps and shortened teeth on the cassette to help with shifting. They all have that now. Also, HG chains supposedly meshed with those ramps for better shifting. HG chains also had stronger rivets where the rivets were peened right around rather than just on two cords of the rivets' face.

All modern chains of say 8-speed and above are this by definition.

 

[youngoldbloke]

Just out of curiosity if the op buys a Shimano HG casette will he need to buy an HG compatible chain or doesn't it work like that any more?

Shaun (from the 1970's)

I never have, just whatever chain was at the best price at the time, KMC, Shimano, SRAM. I certainly wouldn't change the chain at only 300 miles, and if it is noisy I'd be looking for another cause

 

[midlife]

Thanks . I'm old enough to remember the first Shimano casette type hubs and the introduction of Uniglide

Shaun

 

[Yellow Saddle]

Well, we don't know how worn the chain is. Unless that is established, my advice would be change both. If is gets measured, decide accordingly.
That aside i might consider waiting a while, until he has extracted a bit better value out of the bits on the bike.

OK, that's clear. Why not instead just educate the bloke and tell him how a worn chain will affect a new cassette instead of just telling him to buy a new chain as well. It's a rhetoric question, BTW.

 

[GlenBen]

Well the chain checker says its not worn to 0.5, so ill keep that on for now.

With regards to chain length, im looking go go from 32 biggest to 25. Is there a set amount i shoukd be removing?


Alsoooo, ive seen an ultegra 9 speed cassette for £4 more, would that work/be any better than the cheap one?

 

[Ajax Bay]

With regards to chain length, im looking go go from 32 biggest to 25. Is there a set amount i shoukd be removing? Alsoooo, ive seen an ultegra 9 speed cassette for £4 more, would that work/be any better than the cheap one?

You should certainly take one link (ie one inch) out of your chain which, after 300 miles will be almost as good as new btw, so I don't think even 'conventional wisdom' would suggest changing it. Depending on whether the chain was slightly 'long' before, you could probably take out a second link (ie two inches in total). The 32t sprocket requires 1 and 3/4 inches longer than the 25t.
The Ultegra cassette is probably worth getting, at only £4 more, mostly so you can say 'I've got an Ultegra cassette on'. The HG50 cassette is fine and might last longer: it will be heavier (grammes). Hold onto the old cassette (keeping with it a note of how many miles it's done): you may need extra teeth in them thar hills, at some future date.

 

[si_c]

[QUOTE 4739014, member: 9609"]I will do a more in depth post at a later date, however; On the cassette I bought a couple of years back I replaced all the chains when they got to 0.5% (one got to 0.56%) and after 8 chains and about 7500 miles the 9th chain started to slip in the same way they do on a worn casstte. I kept 4 of the old chains (I had meant to keep all 8 but it is a total mystery where the other 4 are) And I am now rotating those chains every 100 mile, they are all up to about 0.7% now and still working fine - I will keep going with them until failure so it will be interesting to see what happens in the long term, (maybe another year)[/QUOTE]

Respectfully, you're bonkers. But I like it.