Daft question nr 2

thejackal

Retro Guru
On one of my current projects, I have a XTR rear mech set up with grip shift changers.

In a couple of gears, ie 2/3 and 5/6 the chain keeps jumping around from one gear into the other and back again and so on and on. It will not stay in the selected gear. Doesn't seem to matter which of the front rings then chain is on. In the other gears it is fine. Does the cable need tightening? Do I need a new rear mech? Could it be a cassette problem?

Any suggestions folks???
 
I didn't think you could run that combination. I don't think Shimano would recommend that. But what do they know?? They just what you to use only their kit. Which maybe why your having that problem? Or just a little bit of more adjustment is needed. But i'm no tech with gears :cry: I wish
 
Couple of ideas:

Long shot, but is your XTR mech a bit old and knackered (ie. floppy) which could lead to ghost shifting?

No crap between the sprockets on your cassette (bit of 'wound up' grass or compacted mud)?

Old cassette and new chain or vice versa?
 
Good point - does the gripshift say 1:1 on it anywhere- in which case it isn't compatible as shimano is (I think) 1:2
 
Daft question

Thanks for the suggestions guys.

The mech is a mid 90's XTR (not sure which one) which could be old and flopy, as opposed to the Gripshift/ Shimano set up which works fine on my other bikes.

Is there any hope for it? Cn I get a new spring. Or is it time to delve depp into my pockets and see if anyone on here has a similar for sale?
 
it's probably not the spring that's the problem but the bearing surface. Can you feel any 'play' in the mech if you try an wiggle it from side to side?

Unless it's been really abused though I would have thought XTR shouldn't fail like that... my well used XT's from the same era have no play.

If you do want to replace the spring I don't know if you can still get them but I put in a RAW Powerspring which means it works a lot better with Gripshift as it pulls the derailleur towards the higher gears with more force. Works a treat. Cost about £5 BITD. Bit a of a bugger to fit, mind!
 
thejackal said:
In a couple of gears, ie 2/3 and 5/6 the chain keeps jumping around from one gear into the other and back again and so on and on. It will not stay in the selected gear.
I had the exactly the same problem with SRT-800's and a good condition XTR M900 mech with new chain and cassette. Couldn't get it to work properly. Tried new cables, mech spring....

Fixed the problem with some thumbshifters. Sold the SRT-800s on here :LOL:
 
Had a similar problem myself, jumping between gears for no reason. Turned out it was a stiff link in the chain.
 
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