New chain skips under torque [solved]

[miklekrs]

Your chain became so worn out from use that it ruined one or more of the sprockets of your cassette. You may also have damaged one or more of your chain rings.

Unless you have a Campagnolo rear hub, you just need to source a cassette with the same number of sprockets. This is also an opportunity to tweak your gear ratios if you want, so long as you don't exceed the tooth difference capacity if your rear derailleur. If you never use your current lowest gear you could, potentially, fit a cassette with a smaller largest sprocket. This will give you a higher bottom gear, but give you more gears in the range you tend to use. If you currently have a 13t smallest sprocket, opting for a 12t or 11t would deliver a higher high gear. If in doubt, simply replace your old cassette with a new one with the same tooth numbers and it'll work as its creator intended.

Every 'Shimano compatible' cassette will work whether SRAM, Miche, Shimano or any of the many off brand cassettes you'll find on ebay.

i haven't always used all the gears top to bottom, so clearly shouldn't skip on all of them?
Thanks

 

[mickle]

i haven't always used all the gears top to bottom, so clearly shouldn't skip on all of them?
Thanks

What's the question?

 

[Ajax Bay]

Fine - if the shifters have been replaced as well with 9sp ones (think unlikely), get a 9sp cassette (no spacer btw, in case there's one there 'left behind') either SRAM or Shimano - will make zero difference. Don't know how you can say the shifting is "smooth" and in the same breath say "1 gear doesn't always shift".

every time i go uphill or i put some force on the pedals the chain jumps/skips on the casette for some reason

I think you'll find that the chain when under 'some force' only skips on a few of the sprockets, normally the middle ones which are those which get most use. But whatever, you need a new cassette.

i have a 9 gear SRAM on it currently, so previous owner must have had it replaced at some point, front chain ring is also seem to be not the factory one. explains why 1 gear doesn't always shift unless held it lightly

Front chain ring irrelevant to the symptom described. Make and model of chainset? I wonder if you have a chainline misalignment.
Not certain what you mean about shifting: how many clicks do you get from the shifters? Nine?

 

[katiewlx]

As others have said, cassette needs changing too. We rarely swap chains for customers without swapping the cassette as well: usually we swap the chain wheel too.

blimey, my bike in the last 11 years has gone through 0 chain rings, is on its 2nd cassette, 3 sets of jockey wheels and about 8 or 9 chains that either links broke or it reached 100% wear on my park measuring tool. theres no way Id be doing a full swap out everytime for a chain replacement

 

[Webbo2]

blimey, my bike in the last 11 years has gone through 0 chain rings, is on its 2nd cassette, 3 sets of jockey wheels and about 8 or 9 chains that either links broke or it reached 100% wear on my park measuring tool. theres no way Id be doing a full swap out everytime for a chain replacement

In that time I’ve ridden to the shops twice and the chippy 3 times.🤣🤣🤣🤣

 

[Andy in Germany]

blimey, my bike in the last 11 years has gone through 0 chain rings, is on its 2nd cassette, 3 sets of jockey wheels and about 8 or 9 chains that either links broke or it reached 100% wear on my park measuring tool. theres no way Id be doing a full swap out everytime for a chain replacement

That's the advantage of doing your own maintenance: you can decide what you think needs replacing.

The problem is that we have to offer a guarantee on what we sell and our work, so policy is that unless there's a good reason, everything gets changed to avoid angry customers demanding refunds.

 

[Ming the Merciless]

everything gets changed

Worn chain? Time for a new bike madam

 

[Andy in Germany]

Worn chain? Time for a new bike madam

With some of the wrecks we see, it would be the safer option...

 

[miklekrs]

Fine - if the shifters have been replaced as well with 9sp ones (think unlikely), get a 9sp cassette (no spacer btw, in case there's one there 'left behind') either SRAM or Shimano - will make zero difference. Don't know how you can say the shifting is "smooth" and in the same breath say "1 gear doesn't always shift".

I think you'll find that the chain when under 'some force' only skips on a few of the sprockets, normally the middle ones which are those which get most use. But whatever, you need a new cassette.

Front chain ring irrelevant to the symptom described. Make and model of chainset? I wonder if you have a chainline misalignment.
Not certain what you mean about shifting: how many clicks do you get from the shifters? Nine?

A bit of digging and i found out that the bike is made 2011/june as i've found out from the vin number. So now i could look up the actual specs, as i think trek official only shows the spec of the latest variant from 2016, so the cassette is a SRAM PG-950 11-26 and i have options upto 11-34. thanks everyone for your help once this is fitted i will let you know how it went.

 

[Ajax Bay]

the cassette is a SRAM PG-950 11-26 and i have options upto 11-34.

Be aware that if you replace the current cassette (which needs replacing) with a cassette with its largest sprocket >28t, your new chain will be too short. [This is on the assumption that the 'old' chain - mentioned in the OP - was the correct length.]

 

[miklekrs]

Be aware that if you replace the current cassette (which needs replacing) with a cassette with its largest sprocket >28t, your new chain will be too short. [This is on the assumption that the 'old' chain - mentioned in the OP - was the correct length.]

i've removed 6 links from a 116 link chain. one way to find out. but should be ok i guess.
Thanks

 

[katiewlx]

That's the advantage of doing your own maintenance: you can decide what you think needs replacing.

The problem is that we have to offer a guarantee on what we sell and our work, so policy is that unless there's a good reason, everything gets changed to avoid angry customers demanding refunds.

and thats fair enough, funnily enough my chain started misbehaving out today on a ride, so it might be time for its next swap, and I might have to consider the chain ring,as it was highlighted last time I serviced the bike it was getting worn to the point of need to start thinking about replacing it, which would be lbs job, I can handle most maintenance but probably not that to be fair.

 

[Pat "5mph"]

Mod Note:
I have moved the posts about the 12 speed SRAM set up in their own thread.
Here.

 

[miklekrs]

Update: bike is fixed, new casette SRAM PG-950 11-34 and kmc z9 chain sized, derailleurs indexed, fixed under 40gbp and rides like a dream. It really puts some new bikes to shame. loving it.