Help! Wheel swap is driving me nuts

Discuss light weight issues concerning mountain bikes & parts.

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Gregorio
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by Gregorio

Ok I am baffled.
On my 29er recently started having problems with rear der adjustment when swapping rear wheels. One is a DT Swiss Hub and the other is a Novatec. New Cassettes, chain and der pulleys...new cable as well.
I set it up on one wheel and it shifts perfectly fine, switch out rear wheel and its not even close. I am not exactly sure when this started happening but over the summer I did have the Novatec apart to replace bearings and I have a feeling that may have something to do with it.

Any advice???

by Weenie


rijndael
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by rijndael

Use micro-shims to space the cassette so it'll line up with the other.

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Benno
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by Benno

Something is probably wrong with your spacing. Either you didn't put your wheel back together correctly, or the cassette is missing/has too many spacers. Also I have seen a company accidentally ship a 10sp cassette with 9sp cog spacers.
You say everything is new, so lots of potential for error.
Measure the width of the cassette and how far it sits from your dropout to start. Something should be different.
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Oswald
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by Oswald

To find out which of both wheels is causing this, I would either
take a third wheel and try that in your bike
or
put both your wheels into a second bike.
That way you will see what wheel is causing this. Then check the hub, cassette, ... on that wheel.

TheRookie
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by TheRookie

Common for different hubs to put the cassettes in different positions, Novatech tend to sit them further inboard than other, in fact versus a Shimano hubbed wheel mine is exactly a whole gear out.
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Gregorio
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by Gregorio

Is it really that common? I have a lot of different wheel sets for road bikes and have never had this issue before.
I can get each wheel to work fine individually by adjusting the der. so cassettes must be fine.
I will take the novatec hub apart again and see if I can figure it out, maybe try to get in touch with their service dept.

mattr
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by mattr

Gregorio wrote:Is it really that common?
It's almost normal that two different manufacturers wheels will put the cassette in a different place. The reality is that it's normally within the tolerance of the chain/shifter system. Shimano and Campagnolos tolerances for what can be made to work are quite large!

Unless it's suddenly started doing this, I'd simply be taking some measurements and spacing one of the cassettes out. (As long as you have enough lockring engagement)

Getting discs positioned right has similar issues.

DanW
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by DanW

I have 4 rear wheels in the house (Hope Pro II Evo, American Classic, Mavic and Pro-Lite) and all work well without any rear mech adjustment. The discs need to be shimmed but that is the only difference between the wheels. It might be reasonably common but I haven't come across any issues. MTB has been very Shimano dominated until recently with SRAM getting more of the market share so I'd have thought everything should be built roughly the same. No Campag in MTB creating other standards for example.

mattr
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by mattr

The shimano and hopes I have work, eastons and mavics needed a tweak or two.

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dwaharvey
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by dwaharvey

DanW: I think the issue here is that there isn't really a standard for the exact location of the cassette - they all space it as far out to the axle endcap as they feel comfortable, in terms of ensuring clearance with all the different dropout/stay designs on the market.

bombertodd
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by bombertodd

I've had this issue in the past. The cassettes are a little off due to hub differences. As mentioned before, micro shimming is the way to go. I measure the gap between the smallest cog on the hanger with a pair of calipers. Then shim the cassettes (shim between largest cog and hub) to match the distance. Most hubs seem to work without tweaking, but I notice an improvement across all my wheels when they are all shimmed to the best of my abilities.

Gregorio
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by Gregorio

where can I get micro shims? I searched google but did not see anything. I think BB spacers are the right diameter but probably too thick.

mattr
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by mattr

http://www.wiggle.co.uk/shimano-cs-hg-1 ... et-spacer/
1mm? 30 seconds with a vernier will tell you how far out you are, and if you can get within 0.5mm , the floating top jockey will take up any extra.

bombertodd
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by bombertodd

mattr wrote:http://www.wiggle.co.uk/shimano-cs-hg-1mm-sprocket-spacer/
1mm? 30 seconds with a vernier will tell you how far out you are, and if you can get within 0.5mm , the floating top jockey will take up any extra.



+1

I think those are the same spacers I use.

by Weenie


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