Replaced chain,reasons for slipping gears if not cassette

danielsbrewer

Hello,

So for the first time ever I changed the chain on my bike last night. I had brought a chain stretch tool and waited until the chain had stretched by "0.75" before replacing it. Now this morning a couple of the gears are slipping (5 & 6 out of 8 at the back when in the central chain ring). I have had a look at the cassette and it doesn't look shark finned at all. Is there anything else that is causing the slips? Could it be the indexing?

As you may have guessed I am very new to this maintenance stuff so be gentle.

nicklouse

things it could be.

worn chain ring.

stiff link in the chain

freehub on the way out

rotate the cranks backwards while watching the rear mech. Does it seem to "jump"?

if yes you have a stiff link.

is the chain the same Speed?

danielsbrewer

I don't think it is a worn chain ring as it was replaced at the same time as the cassette when the last chain was put on. Definitely the right speed chain.

I will have a look at the stiff link, thanks.

How would you know if the freehub is on its way out?

boneyjoe

I'd recon its the casette unfortunately. Check if the same gears slip in the other chain rings. If that happens, I'm pretty sure your cassette needs replacing. It literally only takes a millimetre of wear to cause a problem, which is hard to see with the naked eye.

MrChuck

boneyjoe wrote:

I'd recon its the casette unfortunately. Check if the same gears slip in the other chain rings. If that happens, I'm pretty sure your cassette needs replacing. It literally only takes a millimetre of wear to cause a problem, which is hard to see with the naked eye.

+1

Freehub failure is fairly unusual, whereas cassettes are constantly wearing. Indexing should still be OK if you didn't mess around with it when you changed the chain.

IME worn chainrings with a new chain means a lot of noise and roughness- you'd know if this was the case.

WesternWay

If I were a betting man I would say the cassette.

I have just had to do mine, I think that it is all the winter's grit catching up with me.

Cassettes seem to be the one part of kit where you generally think "oh, that is not as expensive as I feared", so a not terrible experience (unless you have a posh set :-)

Don't do as I did though and think you can do it easily without a chain whip. I tried jerry-rigging allsorts last night before finally managing with an old bit of chain wedged in the claw of a claw hammer.

danielsbrewer

So it looks like I will have to get a cassette then . I currently have a Shimano HG50 cassette (8 speed) but an SRAM PG820 Cassette seems considerably cheaper (http://www.chainreactioncycles.com/Mode ... elID=31547), any reasons not to go for one of those?

If it is the cassette I now feel super confused about the use of a chain stretch tool, what is the point of changing it at 0.75 if I have to buy a new cassette every time? If I leave it to 1 will the chain rings be warn out too?

I have a chain whip already as part of a set, so no worries there.

danielsbrewer

So I replaced the cassette and that sorted out the problems. Thanks. Still don't understand why the cassette was unfit for purpose despite changing the chain at 0.75 stretch. hmmm

nyanza

Still don't understand why the cassette was unfit for purpose despite changing the chain at 0.75 stretch. hmmm

I had exactly the same problem - only had 0.75 stretch on an HG50 cassette but the new chain skipped immediately. Perhaps the engineering of this particular cassette is more sensitive to chain stretch than other cassettes.

danielsbrewer

Ahhhh interesting. I wonder if this non-shimano one will be any better.