After a ride today, I noticed my rear wheel wasnt tight. It turned out there was play in the bearings. Once off the bike, they were really rumbly and rough when turned. Looking online they are cup and cone bearings.Whenever I've had these before, the bearing surface has worn, thus making the hub scrap. What chance have I got that these could be repaired with new ball bearings? The wheel is 8 months old, it came with my new Cotic Jett, so writing it off after 8 months will be rather disappointing. Oh, and it hasnt been jet washed, in fact it hasnt been washed much at all, not that its filthy, it just stays the same ‘patina’!
This is my experience of cup and cone bearings.
i did read once the the cup is a piece of hard steel pressed into the aluminium. I’ve often wondered if it would be possible to drift them out. If you can then maybe you could buy a hub and swap the cups
Or just buy new balls, pack with grease add keep riding. I’ve had bike were the bearings felt terrible. But in practice they were fine to ride
Dismantle the hubs and inspect them before worrying too much. The cones and balls are available as spares - you will be unlucky if the race has been damaged- unless they have been poorly adjusted for an extended period. They might just need grease!
Buy some high quality balls and replace them - uniform shape is what you’re after. Get the part number for some XT ones ( check sizing) as I think Shimano OEM XT bearings are pretty good quality. Use the correct grease also and plenty of it.
Have a word with Cotic, wheels shouldn’t do that after 8 months and they’ve always been reasonable.
In the past I've knocked the races out of shimano hubs and swapped them for new ones from a new hub. It was a while ago though (10 years?) and almost certainly not the same hubs as you've got.
Here you go, p15 and 16,
I've always replaced clipped bearings with more individual balls, but the clips might be part of the sealing system. Try re-greasing and re-adjusting first with your grease du jour
If its loose because the cones came undone it might be salvagable. If its wear its effectivly scrap. You could buy another hub and take all the parts from that and rebuild but swapping the hub is easier.
The wheel is 8 months old, it came with my new Cotic Jett, so writing it off after 8 months will be rather disappointing
Disappointing? I was going for unacceptable. I'd be back in touch with Cotic. Bearings might be considered a wear item but there's no way that should have happened so quickly.
OP, I would try @timba s advice first as only one cone is replaceable - the other is part of the axle. Cleaning and greasing may well be enough if it’s been caught in time, I don’t agree that it’s scrap! In my (lengthy) experience the cones are usually the first to wear as the surface area is a lot less than the cup and the cup is the hardest surface. When re-assembling make sure there is a very slight bit of play so that when the axle is tightened and compresses the hub there is still nice free movement. Check for this by spinning the wheel and also moving the rim laterally. Those parts shown in the pdf are all available separately, part numbers will also be on that Shimano site. I don’t think all is lost, let us know how you get on!
Unfortunately, it is ruined. The drive side inner face is scored/dimpled. I cant see a way of replacing that, though I had asumed it was part of the hub, but from the link from Timba above, it may be inside the free hub rather than the hub itself, I’ll need to take it apart further to check that, I just undid the cones, took out the balls,and saw the damage internally. New ball bearings and a lot of grease make it feel a little better, but I’d guess that once out riding, it’d soon fail again. The non-drive side looked like new, with grease in it still, the drive side was dry, with powdery dust all around it. I really dont think it has been abused, so probably a manufacturing fault with little or no grease in it from new. Its done roughly 600 miles, maybe less from new, so not good at all. Thanks all.
@alanl yes, the drive side race is part of the freehub and replacement is possible as a complete freehub. It may well be cost effective if you can do it yourself?
Yes, I can DIY. Thanks. It’s got me thinking that maybe I shoudl start looking for new wheels, well, new back wheel, as I have 2 spare front wheels. I do have a rear from Superstar, though it has a SRAM 12sp. cassette on it, not sure if that’d work correctly with my current 12sp Shimano rear mech.
Further stripping down has shown it is the bearing face in the hub itself, as well as the cone that are worn out. It looks like they are case hardened, and some of that hardened face has come off. No way of repairing that, so a new wheel will be ordered.
Not sure of the link below will work, my web space isnt working too well today, but it shows a close up in side the hub.
Further stripping down has shown it is the bearing face in the hub itself, as well as the cone that are worn out. It looks like they are case hardened, and some of that hardened face has come off. No way of repairing that, so a new wheel will be ordered.
I'd still just get some new balls and seals and rebuild it. I've run them for thousands / tens of thousands of miles even after the bearings start to rumble. The balls don't fall into the pinholes in the races because the cone is supported across the ~4 either side of it. Even hubs that were seemingly scrap with rumbly bearings and grease full of metallic particles were fixable. The bearings are pennies so you've nothing to lose by trying.
I remember my son putting the bearing surface in some cup and cone Shimano wheels in a few weeks of xc racing, warranty refused by Shimano. We just put fresh balls and grease in and ran them for years after, no problems
*pitting
Agreed re new balls and good grease. I’ve done it and got years out of them. Xt balls are very good quality. The cone can be replaced too if you think they’re bad.
A cup and cone bearing with pitting like that can never be 100% again. New balls and grease may make it spin reasonably smoothly but getting it 100% smooth and no play is impossible.
It’s been scrapped already. I’ve tried new balls and grease, it runs really rough. If desperate, I could use it for a few days, but I have a spare wheel with a SRAM cassette, which seems to work ok with the Shimano shifter, so that is on it for the next week or so until I get a new wheel. Those MT620 wheels are available for less than £100, the hubs are £30 upwards, there’s no way I’m rebuilding it with the chance of the C&C bearings failing again, so the next wheel will have cartridge bearings.
It’s been scrapped already. I’ve tried new balls and grease, it runs really rough. If desperate, I could use it for a few days, but I have a spare wheel with a SRAM cassette, which seems to work ok with the Shimano shifter, so that is on it for the next week or so until I get a new wheel. Those MT620 wheels are available for less than £100, the hubs are £30 upwards, there’s no way I’m rebuilding it with the chance of the C&C bearings failing again, so the next wheel will have cartridge bearings.
To be fair on them it's one of those things that's either a bug or a feature depending on how maintenance adverse you are.
C&C hubs can outlast cartridge bearings if looked after, but they do need a bit of periodic inspection / maintenance. If you just want to run them until there's play and then replace then cartridges are the way to go.
Which reminds me I need to strip and service the shimano winter wheels on my road bike 😂