Servicing wheel bearings?

never serviced a set, just replace as and when, seem to outlast BB's and frame bearings massively...

3 for me. Just replace.

Some will tell you not to as it will damage the seals. However, manufacturers suggest cleaning and regressing. Done carefully, they're finding. You can leave them in situ but you may leave solvent being.

Don't hammer them out, you may damage the races. If you can push them out with a screw thread, even better.

Caveat all that with the fact that it's only worth doing on better quality bearing and only if you catch them early enough.

#3 usually for wheel bearings – they tend to last well so just replace when they get rough (you don't typically need a blind puller for wheel bearings).

If you're the type of rider who likes a good grease maintenance schedule then shimano have you covered.

Other bearings such as lower headset and bb can benefit from some grease as a service, but it really needs to be pre-emptive to make a big difference to lifetime. I doubt most of us bother tbh - maybe if you run one main bike, or you have a race bike which gets a lot of attention to detail.

If the bearing is feeling a bit bolloxed then grease will just eke out a few more rides while you order the replacement bearing.

It's usually the rear that could benefit from a service more than the front due to the crud that get's thrown at them - just remove end caps and seals, and regrease if they feel smooth. If rough, I replace them.

Just replace them

When replacing I always fill with marine grease beforehand.

1 to begin with, 3 when 1 no longer cuts it.

Chirs King 1, although will be 2 next time now I've got the special tool

Hope, Zipp and Tune 3

With wheels, I just swap out the races, With headsets and BBs I often just lift the seal, repack with grease and reseal.

Driving out the bearings from some cassette freehubs can be a bit tricky as some aren't designed to be servicable and I've had to punch some small holes in recessed walls to get them out.

IME there's not much grease in them (things may have changed) so filling them is worthwhile.

Isn't the small amount of grease intentional so it doesn't impede the rotation of the bearings?

As wheel bearings they're operating in the way bearings are designed to do, in contrast to in frame pivots.

I'm not sure that the average bearing is designed to work in grotty British conditions or at a slow rotation speed if that matters. I'm not worried about the extra bit of friction, I'd be very impressed indeed if someone could notice it in real world conditions. It's worthwhile doing in my experience.

doesn’t impede the rotation of the bearings?

I meant the balls

Ive always serviced wheel bearings as soon as i can feel them getting a little rough

My method is as follows

Remove bearings from the hub

Carefully pick out the bearing seals using a seal pick tool

Soak the bearing in isopropyl alcohol overnight

Next day using a fine paint brush clean the bearing using the isopropyl alcohol, once clean spray clean isopropyl alcohol into the bearing to flush anything left in there until it runs clear

Next use an airline to blast air into the bearing to dry everything and remove any stubborn bits that maybe still in the bearing

Regrease with the grease of your choice

Clean and refit the bearing seals

weeksyFull Member
3 for me. Just replace.

surely that should read ‘for me, I just replace my bike’. Winking laugh emoji

Once a sealed bearing is running rough its fubar - it will never run right again.  cleaning and repacking might however keep you mobile until you can get a new one

Personally I never overpack new bearings - I believe it damages seals and makes water ingress more likely leading to failure.  Others disagree.

Always buy good quality branded bearings and do not side load them

The thing is, most bearings aren't built specifically for bike use, bike stuff almost always uses industry standard bearings which are generally built for a) higher speed and b) in this size, usually inside something and not very exposed to dirt, weather etc. So low fill is the way to go, and also the grease used is picked to work with that.

For us, that doesn't apply, our fastest bearings are still moving slowly, hundreds of rpm, some don't even spin and rotate through only a few degrees. And often the rubber seal is basically the only protection as we splash through puddles. So a bigger fill is just better, it keeps dirt and water out with trivial downsides. The challenge is that it's possible to damage the seal, if you're clumsy or use inappropriate tools, but as long as you do it well it is simply better. And it's easy to test that, for that matter, you can do one side of a wheel but not the other and see what happens. Waterproof greases tend to be much stickier which is unsuitable for a fast bearing but can work great for us, there's no need to clean out the original factory grease but if you're really obsessive then you can, just be very sure that you're getting new grease thoroughly into it- this isn't so esay with caged bearings.

In the end, none of it's really transformative as long as you use quality bearings in the first place. But especially in the winter months if you want to get the maximum life out of hte parts and reduce future maintenance/replacement/failure, then greasing is probably worth it. Bikes that sit in a cold garage getting used less can also benefit more.

As far as servicing goes, once a sealed bearing is dirty it's very hard to clean, pretty impractical in situ, and taking them out usually means hammering out hte central race which will often damage the bearing enough that it's not smart to refit. And once it's rough it's knackered, you can extend its life but you can't fix it. So for most people once you have a bearing in the frame it doesn't get serviced, it just gets replaced.

I'll happily repack a worn bearing just to keep it going a little longer especially when it's inconvenient to replace, ie, I am being lazy or the timing's bad. And you can run a worn bearing for a very long time, situationally- frame bearings tend to get crunchy and sticky and can sieze completely and damage parts, but wheel bearings tend to loosen up. The big plus of sealed bearings is just that you have to try rreally hard to ruin the wheel or bike or whatever, it can be done but it's not like cup and cone or some bushings where even a little neglect or not noticing a problem can be seriously bad.

I find the bearings in the XD drive freehub don't last very long, I replace these twice a year, the axle bearings only once per year

3

The manufacturers of the bearings haven't manufactured them to be serviceable. It's a pain in the neck to do. Fair risk of damaging one of the races or the seal. And if you shop around and get better bearings usually pointless after you've taken the stock bearings out. I used to buy in bulk and usually got a set of bearings for about 20 quid, unless there's a "special" bearing in there. Which you can usually source for less than the hub manufacturer charges if you know where to look.

Haven't needed to buy anything lately as I've got SKF or NTN bearings in pretty much everything now, and they just keep on going, haven't touched one for about 3 years. (So i have a bag of random hub bearings!)

Cup and cone is still where it's at though!

3 for me ideally.

2 happens if it's essential to get riding and 3 can't be achieved at that very moment. If I am doing a clean and repack because they are rough or seized, then its just a stop gap as they are already mostly gone.

1 is not worth it as you won't get them clean.

@nwgiles what size bearings are in the XD freehub please? As Im looking to replace mine but can't seem to find this information. Tried the importers but they haven't provided me with anything...

@keando

https://www.wychbearings.co.uk/6802-LLU-MAX-BO-Enduro.html?gad=1

I use these ones

@nwgiles

Thanks very much for the link. I'll give them a go 🙂

I have just replaced the bearings in a DT Swiss rear wheel after 5 years. The front is still fine. At this sort of interval I am far too lazy to bother servicing bearings