disc wheel not sitting central in frame

[Bodhbh]

Finally got around to cleaning up the hub on a graunchy old wheel with the hope of having a couple of spare wheels for the MTB so can swap tyres easily.

Anyhow, the rear spare wheel does not sit exactly where the orginal one does - the disc rotor just about fits in the caliper but rubs against the side, the cassette is not in the same spot as the gears need re-indexing and re-limiting, and the wheel does not look exactly central in the frame.

Any particular reason why one hub/wheel might sit differently? The bike is a 2005 Rockhopper, the orginal wheel has a lockring mounted disc, while the spare has 6-bolt mounted disc - only difference visually. (sorry I don't have the parts no. or anythign, came across the issue late last night and I'm at work).

 

[RedBike]

Different makes of hub do vary. You can expect your gears / disc to slightly miss-aligned. However, all wheels (if they've been built right) should all sit central in the frame.

Perhaps by adjusting/ re-space that axle, a few shims behind one disc or the other and finally re-dishing the wheel you can get them all to line up with each other.

 

[Bodhbh]

Different makes of hub do vary. You can expect your gears / disc to slightly miss-aligned. However, all wheels (if they've been built right) should all sit central in the frame.

Perhaps by adjusting/ re-space that axle, a few shims behind one disc or the other and finally re-dishing the wheel you can get them all to line up with each other.

Hrmm well that's an idea. Messing with the dishing is a bit beyond me right now, although in time I might use this wheel to have a go (and eBay another spare for the mo). Cheers for the help anyway.

No sure if there is something up with the build on this wheel. It has been retrued twice already after breaking multiple spokes each time. Spokes went on the disc side which I understand is unusual.

Seems unless everything is 'just so' it's as easy to swap tyres over each time rather than mess about with the wheels, and presuable have to mess about moving cassettes about or swapping chains to match each cassette if you have two to stop gear slippage.

 

[RedBike]

You can use two cassettes (one on each wheel) and provided you use both set roughly equally / the chain isn't too worn there shouldn't be too many problems.

But trying to use a newish cassette with a worn chain is asking for trouble.

 

[NickM]

Wheel spacing (meaning side-to-side positioning of the hub shell) on (at least) one of them is wrong by the sound of it. If you have access to a dishing tool, you can find out which. You won't necessarily need to adjust spokes to get the dish correct; it may be simply a matter of correcting the hub spacing - I'd try that first, anyway.

 

[jimboalee]

Spare wheels.

First requirement - same number of sprockets on same series cassette.

Most critical dimension - Frame face on driveside to centre of smallest sprocket.
So the mech does not need adjusting when wheel is changed.

Second critical atribute - rim is centre ( dished correctly ).

With a disc brake, if the sprockets are in the correct position, the disc should be too. But if it isn't, shim the disc ON ALL wheels to be used in that frame.

 

[Bodhbh]

Wheel spacing (meaning side-to-side positioning of the hub shell) on (at least) one of them is wrong by the sound of it. If you have access to a dishing tool, you can find out which. You won't necessarily need to adjust spokes to get the dish correct; it may be simply a matter of correcting the hub spacing - I'd try that first, anyway.

This sounds promising. How would I correct the hub spacing? It's possible to walk the cone nuts a bit down the axel until it holds it in the same position as the other hub? This is the 1st/2nd time I've done hub maintenace so wouldn't be suprised I've moved things and buggered it up.

 

[Bodhbh]

First requirement - same number of sprockets on same series cassette.

Yes, just for the purposes of testing swappign the same sprocket atm, but will get a duplicate (9-speed 11-34 deore one).

 

[jimboalee]

Put the cassette on the spare wheel. With the chain off the bike, offer up the new wheel. Does the smallest sprocket and the upper jockey wheel align when the mech is in top gear position?

If it doesn't, juggle washers between the cone and face nut on the driveside.

Now the mech will shift to each sprocket nicely.

Is the rim centered?

Use a dishing tool and truing jig to get it central.

Does the disc slip centrally between the pads?

Shim the disc mounts.

 

[Bodhbh]

Put the cassette on the spare wheel. With the chain off the bike, offer up the new wheel. Does the smallest sprocket and the upper jockey wheel align when the mech is in top gear position?

If it doesn't, juggle washers between the cone and face nut on the driveside.

Now the mech will shift to each sprocket nicely.

Is the rim centered?

Use a dishing tool and truing jig to get it central.

Does the disc slip centrally between the pads?

Shim the disc mounts.

Alright thanks! Cheers all, I'll give this a punt tonight and see how it goes. The way things appear is everything is too far over to one side, so hopefully this will fix both gear and disc alignment.

 

[NickM]

This sounds promising. How would I correct the hub spacing? It's possible to walk the cone nuts a bit down the axel until it holds it in the same position as the other hub?

Yes

And what jimboalee says. A good way of measuring right-hand side positioning is to lay the wheel flat, put a straight edge on the locknut and use a micrometer to measure the distance from straight edge to outer face of top sprocket (adding 0.9mm for half the thickness of a 9-speed sprocket, if you want an absolute measure).

When everything is right there should be an equal amount (usually 5.5mm) of bare axle sticking out from the locknut on each side of the hub in order to engage the dropout correctly. If the amount is not currently the same both sides, that is a clue about which way to go!

 

[Mr Pig]

I bought a spare set of wheels for my MTB last year. I was going to get the same ones as were fitted originally, Shimano hubs/Alex rims, but was told that they should all line up perfectly no mater who made them. I got a set of Mavic wheels and sure enough they did!

Sorry you're having issues but stick with it. It's worth doing as it's great being able to swap over to road or mud tyres in two minutes.

 

[Bodhbh]

Cheers guys, one problem solved. Had a look at it last night and it was simply a case of moving a spacer from one side of the axel to the other. I've not tried swapping back and forth, but as the disc on the spare now sits squarely between the calipers without scraping as the original does, if there is any difference I can't see it being much or effecting indexing.

It's possible I borked putting the hub back together, but I don't think so as I seem to remember having this issue when I first tried wheel swapping over winter (vesus a brand new touring wheel from Spa Cycles, which I assume is spot on).