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 Post subject: Daft question nr 2
PostPosted: Tue Jul 24, 2007 10:33 pm 
Old School Hero
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Joined: Tue Jun 20, 2006 2:53 pm
Posts: 223
Location: Gods very own Leeds
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???


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 Post subject:
PostPosted: Tue Jul 24, 2007 10:46 pm 
King of the DuckBoard
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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


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 Post subject:
PostPosted: Tue Jul 24, 2007 10:49 pm 
East Midlands AEC
East Midlands AEC
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Location: Derby, UK
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?


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 Post subject:
PostPosted: Tue Jul 24, 2007 11:28 pm 
Gold Trader
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Location: Odense, Denmark
Which model gripshift is it? Not all are Shimano compatible.


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 Post subject:
PostPosted: Wed Jul 25, 2007 8:09 am 
East Midlands AEC
East Midlands AEC
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Location: Derby, UK
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


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 Post subject: Daft question
PostPosted: Wed Jul 25, 2007 8:12 am 
Old School Hero
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Location: Gods very own Leeds
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?


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 Post subject:
PostPosted: Wed Jul 25, 2007 8:26 am 
East Midlands AEC
East Midlands AEC
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Joined: Thu Oct 05, 2006 7:45 pm
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Location: Derby, UK
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!


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 Post subject:
PostPosted: Wed Jul 25, 2007 8:36 am 
Mr Darcy
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Location: Bicester
Is this 7 or 8 speed?
Shimano or Suntour cassette?

Spacing wasn't always the same..


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 Post subject: Re: Daft question nr 2
PostPosted: Wed Jul 25, 2007 9:42 am 
BoTM Winner / retrobike rider
BoTM Winner / retrobike rider
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Joined: Thu Nov 23, 2006 2:12 pm
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[quote="thejackal"]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.[quote]

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:


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 Post subject:
PostPosted: Wed Jul 25, 2007 11:21 am 
Anglian Deputy AEC
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Joined: Mon Oct 09, 2006 6:13 pm
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Location: Livin' in a dust bowl
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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