Chain Slipping on new cassette
Discussion
I recently replaced my chain and my rear cassette, gone fron 12-26T to 11-28T, same make. At the same time I also discovered that my rear derailleur was siezed on the shaft that screws to the frame, so i stripped it down, cleaned and greased it and put it all back together. It now moves freely. However I'm having a problem with the top two gears on my cassette. On the bottom chain ring the chain jumps on the top two gears and on the top chain ring it slips on the top gear. I've messed around with the chanin length and adjusted the B screw but it's still slipping. I'm thinking that the spring in the rear derailleur is past it and not providing enough tension but I don't want to spend more money on something that doesn't work. Is there any way of testing this?
It could be the spring, but I'd check the cables anyway. If you need to change them, check the cable tension - the derailleur may be sat on the cusp of the cog above or below it which would cause it to skip around.
As a general rule (and assuming that the limit screws are set correctly) if the derailleur is struggling to shift onto the bigger cogs, it needs more tension. If it's struggling to shift to the lower cogs, then it needs less tension. Assuming it has one, play around with the barrel adjuster on the mech - have a play around with that.
Of course, you may have already tried this.
As a general rule (and assuming that the limit screws are set correctly) if the derailleur is struggling to shift onto the bigger cogs, it needs more tension. If it's struggling to shift to the lower cogs, then it needs less tension. Assuming it has one, play around with the barrel adjuster on the mech - have a play around with that.
Of course, you may have already tried this.
Unless it's broken, I'd be surprised if it's the spring - it's amazing how little wrap you need for this stuff to work, nor does the cage do a lot to hold it, other than making sure it's going around the sprocket.
I'm not sure from your terminology what combinations exactly are slipping. as others have said check alignment etc. Also see if you can 'feel' if the jockey wheels are touching the top of the sprocket's teeth. Depending on series of your mech, it quite probably isn't designed to take a 28, no matter what you do with the b-screw. My 10speed 105 mech needed the b-screw reversing to make that work (it isn't designed to).
I'm not sure from your terminology what combinations exactly are slipping. as others have said check alignment etc. Also see if you can 'feel' if the jockey wheels are touching the top of the sprocket's teeth. Depending on series of your mech, it quite probably isn't designed to take a 28, no matter what you do with the b-screw. My 10speed 105 mech needed the b-screw reversing to make that work (it isn't designed to).
Edited by upsidedownmark on Friday 3rd June 15:19
It shifts very well.
To clarify, when on the small chain ring it is slipping on the two smallest cogs on the cassette and when on the big chain ring it is slipping on the smallest cog on the cassette.
The 28 fits ok with some b screw adjustment, it's the smallest cogs that seem to be an issue.
I'll have a look at cable tensions.
I'm trying to avoid goin near to a shop. It's a Boardman so independent cycle shops tend to roll their eyes and not want to help and Halfords are not much good.
To clarify, when on the small chain ring it is slipping on the two smallest cogs on the cassette and when on the big chain ring it is slipping on the smallest cog on the cassette.
The 28 fits ok with some b screw adjustment, it's the smallest cogs that seem to be an issue.
I'll have a look at cable tensions.
I'm trying to avoid goin near to a shop. It's a Boardman so independent cycle shops tend to roll their eyes and not want to help and Halfords are not much good.
Devil2575 said:
Fixed.
I'd split the chain and remade it a couple of times and there were a couple of stiff links. All sorted now and it going great.
You're best buying a new chain and a power link if you have split and remade it with a chain tool. I'd split the chain and remade it a couple of times and there were a couple of stiff links. All sorted now and it going great.
it will probably snap and leave you stranded in the middle of nowhere in the near future!
gp1699 said:
Devil2575 said:
Fixed.
I'd split the chain and remade it a couple of times and there were a couple of stiff links. All sorted now and it going great.
You're best buying a new chain and a power link if you have split and remade it with a chain tool. I'd split the chain and remade it a couple of times and there were a couple of stiff links. All sorted now and it going great.
it will probably snap and leave you stranded in the middle of nowhere in the near future!
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