Shimano Road/ Mountain gear mix
Hi
My wife rides a road bike that until recently had a compact chainset and 9 speed 12/27 cassette. The shifters are Dura Ace 9 speed.
She had a knee operation in March and now finds it uncomfortable to climb out of the saddle. We live in south Somerset and spend a lot of time riding the Dorset hills. To enable my wife to climb hills in the saddle I fitted a 11/32 cassette and changed the Dura Ace rear mech for a Shimano XT SG rear mech. The problem is, she now gets ghost shifting. It's a new cassette and chain and the XT mech is about three years old but has not been used much or bashed at all. I have set the rear mech up as discribed by Shimano and it works great inthe small cogs but jumps and ghosts two or three down from the 32 tooth cog.
Any ideas?
Should I be using a XT SGS on this setup?
Please don't suggest a triple, she had one and hated it.
My wife rides a road bike that until recently had a compact chainset and 9 speed 12/27 cassette. The shifters are Dura Ace 9 speed.
She had a knee operation in March and now finds it uncomfortable to climb out of the saddle. We live in south Somerset and spend a lot of time riding the Dorset hills. To enable my wife to climb hills in the saddle I fitted a 11/32 cassette and changed the Dura Ace rear mech for a Shimano XT SG rear mech. The problem is, she now gets ghost shifting. It's a new cassette and chain and the XT mech is about three years old but has not been used much or bashed at all. I have set the rear mech up as discribed by Shimano and it works great inthe small cogs but jumps and ghosts two or three down from the 32 tooth cog.
Any ideas?
Should I be using a XT SGS on this setup?
Please don't suggest a triple, she had one and hated it.
0
Comments
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have you set the B screw correctly?
check the condition of the jockey wheels.
It should all work fine."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
Thanks Nick
I have overlooked the B screw on the XT mech. It was on a Raleigh Audax bike with a triple and 12/25 cassette so is probably way out. I will check in the morning.
You may have saved me from being moaned at on the club run tomorrow.
Ned0 -
The B screw turned out to be adjusted just about where it should be and the jockey wheels are still in good nick (correct side to side movement).
Luckily I was riding in a different group on this mornings club run. I did however get it in the neck at the cake stop when she caught up!
any ideas?0 -
nope sorry, can only really be set up as everything should work fine as it is compatible and all the same spd.
maybe the chain line is just not too nice on the big cogs,, but it should still work OK."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
Thanks Nick
I will continue tinkering. I did wonder, if there was sufficient capacity in the XT mech. I see from Shimano literature that the model I have has a total capacity of 33 teeth. Most Mountain Bike mech's have 44 teeth capacity. I might try an LX mech off my boy's bike.
cheers
Ned0 -
what are the front cogs ( not been mentioned yet) range?"Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
it's a setup thing, as suggested.
I put a 11-32 on the wife's bike, with an XT mech, for the Fred Whitton on Sunday. No problems. Check cable routing, check that click two isn't setup on sprocket one (I've seen it happen), check loose mech hanger, frame alignment?Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer0 -
The chainset is a Shimano compact 50/34, which shifts perfectly. The chain alignment should be as good or better than a triple that the XT rear mech was designed to work with.
The frame dosen't have a removable mech hanger and the alignment is fine.
I will check the cable routing and gear setup again as you have suggested.
cheers
Ned0 -
Where the rear mech cable goes into the pinch bolt (just after it's exited the barrel adjuster) it needs to go in a straight line to one particular side of the pinch bolt. Check it's not going diagonally to the wrong side of the bolt.
It's a subtle thing but it'll completely mess up the shifting if it's wrong.
I have a Cyclocross bike which uses MTB components at the rear (11-32t cassette and LX mech with longest cage, SGS I think) and I had trouble getting the indexing to work a while back, then discovered I'd clamped the cable on the wrong side of the pinch bolt... After much head scratching.0 -
Maybe also check that the hub is in good working order and bearings are in good nik and there is no play in the wheel.
I had loose cones on my hub, which allowed the wheel to move side to side enough to cause random ghost shifting. Took me ages to realise, went through the normal setup and trouble shooting multiple times before I found the fault.0 -
We got there in the end. Yes perfect shifting, with a twist.
A mountain biker I work with gave me a XTR SGS reverse pull, long cage rear mech to try. I set it up this afternoon and low and behold, really smooth indexing.
OK, the levers now work in reverse but the shifting is perfect. I rode the bike with this setup for an hour and it didn't misbehave at all. It's very weird shifting in reverse after years of conventional shifting. I will probably return the XTR mech and get a normal one in the same spec.
Anyway I now know the rear mech was the problem all along.
Thank you all very much for your help and suggestions.
Ned0
