Partial or full replacement of rear hub?

[mdskids]

I just serviced the rear hub of my touring bike (Shimano Deore XT) as I was getting some odd noises from the rear which I couldn't identify (occasional random ticks/clicks which are a little worse when I freewheel or backpedal - perhaps something catching in the freehub?). On inspection of the hub, the drive side grease was brown (=water?), the drive side bearings are discoloured and the drive side cups & cones a little pitted, but not too bad. I've had this issue before, which started about a year ago because I didn't notice the hub axle nuts had become loose, giving a bit of play. My commute can be pretty wet and mucky, so I think this is when some water got it. Back then I serviced the hub and replaced the bearings (drive side only), and it had been ok until now.

My question is - if I buy a new hub, could I replace just the freehub, the axle and bearing. This would be much easier than having to rebuild the whole wheel (especially as I'd be dismantling the new hub and regreasing it anyway). I assume this would give me new cones on both sides and a new cup on the drive side. As far as I can tell, there's nothing wrong with the existing cup on the non-drive side. Buying a whole new hub appears to be easier and more cost effective than trying to buy a replacement freehub and axle.

I hope this makes sense - Is this recommended, or I should I just be rebuilding the wheel with a whole new hub? The wheel and hub are about 3 years old (handbuilt from Spa cycles) and has done approx 10,000 miles.

[peetee]

Buying a new hub to supply the parts to fix worn bearings is often the cheaper option. It is likely that there will be uneven wear on the hub bearing face so I would suggest replacing the entire hub. Pay particular attention to the preload on the bearings once the wheel is rebuilt. It is often the case that Shimano hubs are too tight ‘out of the box’ and wheel tension can also have an effect on the the ready-to-ride bearing adjustment.
FWIW, I would suggest that the issue you have had was probably a result of water and muck finding it’s way into the hub via the rear freehub seal. The axle seal would not be affected by a small amount of play in the bearings.

[rareposter]

Three years is nothing for an XT hub unless it really is hammered - I had XT and XTR ones that lasted in excess of double that time and distance and that was MTB.

I'd look a bit at the bigger picture - how worn is the rim? There's little point in buying and fitting new parts to the old hub if the rim itself is worn out, that really is new wheel time.

If the rim is sound, then the easiest option is to buy the required parts for your current hub (or to buy a whole new XT hub, same as the old one and strip it, that may work out cheaper as you've already indicated).

Depending on how worn it all is, I might be tempted to just run it into the ground over winter then sort it out in spring.

[Brucey]

you can indeed dismantle a new hub to get the bits you need but [once the axle is out] you need to temporarily install a cassette and use a good chain whip on the new hub to do it.

[cycleruk]

I have recently replaced a freehub and also done a complete hub change on another wheel. (conversion to 11 speed.)
I don't know if this is what Brucy means but I found the awkward bit, when removing the freehub from the new hub, was undoing the new freehub bolt. It was really tight and took some force to undo it. (A new hub was cheaper than just purchasing a freehub.)
On just a spare hub there is nothing to grip so a means of holding it will have be devised if you don't want to damage it.
(Usually a hub is in a wheel and the rim can held while undoing the freehub bolt.)

See this topic if deciding to change the complete hub.
viewtopic.php?t=158553

As far as I know the non-drive side cup is integral with the hub and if you want to replace the cup then you have to replace the whole hub.
Obviously the freehub is also the drive-side cup and only your inspection can decide if it needs replacing.
Otherwise just new cones and balls can be sourced and fitted.

[mdskids]

Thanks for the help, everyone.

It's a 6 bolt disc wheel/hub, so the rim is absolutely fine.

I think that (as suggested) I'll continue to run the current hub over the winter then replace part or all next year. If I do just replace the bolt and freehub, I can bolt an old brake disc onto the new hub, and hold this in a clamp, which should make it easier removing the freehub.

I have a 2nd set of wheels for this bike (27.5", which I use when I need wider tyres, as my Tour de Fer only has enough clearance for 35/38 on 700c wheels) so I may just swap the wheels and take my time rebuilding the old wheel on a new hub. It'll be good for my wheel building skills. (I don't have the measuring kit for properly tensioning spokes, but I do have a decent ear for music, so before I dismantle the wheel, I'll make a recording of a few plucked spokes on each side, and aim for the same notes!)

Any tips on keeping the water out of these hubs in the future? Is it worth smearing the outside of the seals with grease, or is that just going to be a crud magnet? And what's the general consensus on sealed hubs on a touring bike?

Cheers

[Brucey]

.....Any tips on keeping the water out of these hubs in the future?.....

IMHO the very best thing you can do is to install a lube port and then use it.