MTB wheels with thru axle

[TheGreatSoprendo]

I have a feeling this might be a stupid question, but I'm stumped, so here goes...

Having pretty much destroyed the crappy Alexrims wheels that came with my Norco, I managed to get a good deal on some used Crankbrothers Iodine's to replace them. Fitted them this morning, including new discs, new cassette and a conversion kit to convert the rear to take 9mm QR. All good so far.

The issue came when I tightened up the front wheel which has a 15mm thru axle (both the original wheel and replacement wheel are 15mm thru axle) and noticed the wheel wasn't spinning freely. It span fine with the QR released, so not a brake binding issue.

When I took the wheel off again I noticed that the middle of the hub (the bit shown by the arrow in the pic) doesn't spin independently of the rest of the wheel as it does on the old wheel, hence tightening the QR tightens the form onto the hub which cannot spin freely. As I said, I'm a bit stumped by this and not sure what I need to do next!?

[AndrewEH1]

Do the bearings on each side of the hub turn freely?

[BadgerBenji]

It's it a 15mm axle or a 20mm axle wheel?

[TheGreatSoprendo]

It's a 15mm wheel and, no, nothing spins freely. The whole wheel and hub will spin, as one, on the axle as long as it's not done up tight but that's obviously not right!

[AndrewEH1]

Yep, something isn't quite right there...maybe take it to a LBS in case you're doing something silly.

[deadtom]

unless the design of the Iodines is much different to the set of cobalts that I have here, it sounds like your bearings are shot I'm afraid

[Kermit power]

deadtom said:

unless the design of the Iodines is much different to the set of cobalts that I have here, it sounds like your bearings are shot I'm afraid

Hence the good deal, possibly.

Still, it shouldn't be ruinously expensive to replace the bearings!

[Tiddy1]

You can get the bearings from Wych bearings for about £12 each, see attached link

http://www.wychbearings.co.uk/CH-61805-2RZ-CERAMIC...

just check the numbers before ordering

[TheGreatSoprendo]

Thanks Chaps. So, I removed the brake disc with the intention of removing the endcaps and checking out the bearings but lo and behold, without the disc in place the hubs span perfectly! It seems the inner portion of the disc is seating on the outer edge of the rim, stopping it rotating freely. You can see where the seat of the disc is scored (yellow arrow) from seating on the endcap (orange arrow). This is a brand new Shimano XT disc, by the way.

I thought it might be an issue with the seating of the endcap but having reseated it a couple of times and given it some welly with a rubber mallet, it seems to be as "seated" as it's going to get.

So I've made some progress with the diagnosis but I'm still stumped on the solution...

[TheGreatSoprendo]

They'll be nice when they work!

[WinstonWolf]

Either the ID of the disc is too small or you're missing a spacer.

[Kermit power]

Was the disc definitely fitted the right way round?

[TheGreatSoprendo]

The disc was definitely the right way around. I did try it the other way around just in case I was going mad, though, and had exactly the same issue.

[deadtom]

how much is the interference? you can get super thin shims which usually go on the outside of the disc to act as a security measure, but if you put those on the inside then it would space it out by ~ 1/2 mm

failing that, just buy some all steel rotors. they don't look as fancy but they will solve your problem.

or there is a slim chance that the bearing has not been seated properly on that side, but it's unlikely

[Kermit power]

deadtom said:

how much is the interference? you can get super thin shims which usually go on the outside of the disc to act as a security measure, but if you put those on the inside then it would space it out by ~ 1/2 mm

failing that, just buy some all steel rotors. they don't look as fancy but they will solve your problem.

or there is a slim chance that the bearing has not been seated properly on that side, but it's unlikely

I'd say there's a greater chance that the bearing hasn't been seated properly than that there's a problem with the rotor. XT stuff is pretty universally praised for its quality, so I think it would be quickly highlighted if there was a problem with XT rotors.

[deadtom]

Kermit power said:

so I think it would be quickly highlighted if there was a problem with XT rotors.

it wouldn't be a problem with the rotor as in it's made wrong, but being an ice tech rotor it has the alu central spider which needs to be thicker so that it is strong enough, which means maybe it extends inward from the mounting bolt PCD more than a plain steel rotor would (I haven't ever actually measured one to be certain but it looks to be the case). This is also why the actual mounting surface is indented as seen in the OP's photos; so that the alignment is correct even with the thicker spider. If this is the case then you would probably also have similar issues trying to mount the hope floating rotors and the superstar ones too as they also have alu spiders.

It is possible that the bearing has not been fitted properly, but the difficult part of pressing bearings is getting them started and going in straight, so by the time you get 90% of the way there then it's unlikely you would not get that last 10%

edited to add: The more I think about it, the less convinced I am by my own theory. OP I would check the hub is properly assembled and compare the bearing depth with the other side (that assumes that the other side is correct)

Edited by deadtom on Tuesday 23 June 23:48

[Kermit power]

OP, is the bearing rotating freely with the rotor and axle removed?

Looking at your yellow and orange arrows above, it looks as though it is the outer bearing race which has caused the scoring, and to do that, it presumably has to be rotating, which doesn't make a lot of sense!