Maintenance Reminder: Repack those Sealed Bearings

A week after a long ride in the rain, I thought that it might be a good idea to check to see if any moisture made its way into my sealed bearings. I recommend this to anyone, even if you have a brand new unicycle or new bearings. My unicycle is fairly new, only a year old and I only ride on the street. I was really surprised how much smoother my ride is now that I repacked the bearings. It appears, at least in my case, that the bearing manufactures don’t use enough grease.

Here’s the process that I followed:

First, I took off the wheels and cranks. There is no reason to take off the bearings from the wheel. Unless, of course, they are so dirty that they either should be soaked in a solvent or replaced. Now, remove the seal. I used a tiny flat screw driver, commonly used to fix sunglasses/eye glasses. Make sure that you only remove one seal. Of course, if you didn’t take the bearings off the wheel, you will only see on seal to take off. We don’t want bearings falling out. It should just pop off. Be careful not to damage the seal. Once you have the seal off, place it aside. Take a paper towel and carefully wipe the bearings. You’re trying to get all of the dirt and rusty orange stuff out. Clean the seal. Finally, repack the bearings with bearing grease. I found some at an auto parts store for $4 that should last many years to come. Just push as much of that grease in there that will fit. Then, put the seal back on and you’re all set.

I repack my bearings almost three times a year. Granted I ride a lot of different conditions, snow, rain, mud, extreme cold, heat and the worst of all is the sand. I follow the same method that you mentioned above but I use synthetic grease. Also i take off both caps on the bearings, (the bearings wont fall out), then slowly pack the grease in. At the same time I slowly spin the bearings,this works the grease into all of the bearing. YOu will be surprised how much grease you can pack in them.

Lastly when I used to ride a lot of street some riders would clean out their bearings 100% and you could have a wheel that spins for days! I wouldnt recommend this for a lot of people but if you want a wheel that spins freely do it up, but dont expect your bearings to last very long at all.

I’ll have to get some synthetic grease next time. Do you think it’s all that necessary to take both caps off to repack them? The problem I see is having to pull the bearing off the wheel to get to the other seal.

I couldn’t believe the difference repacking the bearings. My peddling felt so much smoother, than even the first day my uni arrived.

Thanks Shannon and Jacob. I cleaned my road uni a little too well with a hose and forced water into a great bearing by accident. I’ve been able to smooth it out with some WD40 but will pry off a cover to get some grease in there. Thanks for the inspiration.


after the careful wipe and before the grease repacking, wouldn’t it be useful to spray the bearing with a cleaning/lubrication product like WD40 to make sure it is thoroughly cleaned (while moving it around) ?

Wd40 or similar penetrating oils are not ideal to clean bearings from experience and everywhere I read.
Many say clean them with a solvent like acetone which it’s residue will completely dry leaving no film or oil. Then re grease or oil with your favorite choice. I prefer a lithium or Teflon grease. Some might like a more specialized waterproof grease or others might even use a grade of bearing oil.
A lot of bearings from the factory yes don’t seem to have enough grease nor be good grease like we always like.
I’m contemplating swapping the steel balls out for ceramics. Like I have with inline skates they are smoother and last longer and roll faster in skates.
Thanks for the write up btw !

I’m not an expert on this, but I wouldn’t think that would be a bad idea if it seems there’s a lot of crud in the bearings. I wouldn’t think it would hurt.

I agree with your maintenance schedule. Every 3-4 months should be a good rule, depending on how hard and where one rides.

You want grease in your bearings. Grease has body.
WD40 is NOT grease – it is in fact a very effective DE-GREASER.

If it gets inside your bearings (intentionally or otherwise) it will destroy the grease, and then you will have bearings without grease. This would be a bad thing.


I think you misread the WD40 post: It is not a bad thing if you meant to use it for exactly that purpose. It was suggested to use WD40 for cleaning, before repacking with proper bearing grease.

I’ve done that for non unicycle bearings, but as was said before, WD40 needs to be cleaned off completely before repacking. Or use something that doesn’t leave a residue for cleaning. If you’re going to use acetone, be really careful because it is also a great paint thinner / paint stripper. Don’t get it on your frame.

WD 40 or brake cleaner are good options to remove the grease. I would stay away from acetone because some bearings have a plastic guide and acetone is very agressive towards plastics. And if you do the cleaning without removing both seals, they wouldn’t like it either.

Wd40 residue after you wipe if off is still in a small way there. Usually both outter seals would be removed for proper cleaning and the inner race if it’s not metal will be Teflon. Yes it’s plastic but it’s strong slippery and not affected by acetone whatsoever.
If my 16 skate bearings literally a smaller version of my uni bearings last long as they do then can’t imagine acetone and grease being adverse in larger bearings. You can clean with wd or degreaser but still need to clean that out for a proper job. Acetone is fairly cheap works and dries totally. Avoid fumes and letting it soak into skin. That’s only harm that could come of it’s use

I tend to do a thorough job with degreaser if cleaning bearings, but don’t think WD40 would actually be a bad idea. The actual amount of residue left behind would be pretty small and unlikely to have much affect if repacking with lots of grease - most of WD40 is solvent which evaporates off.

The two primary ingredients of WD40 are essentially white spirit and a light oil. There’s not much point using it as a degreaser, unless you need it’s penetrative, water displacing properties too. Using white spirit alone would be much cheaper.

I love a good healthy debate over the use of WD40!!! :roll_eyes:

… Repacking bearings? I think I’ve done something wrong the last decade… or not done something…
My sealed bearings are so old they’re now unsealed… And I admit I used WD40 a couple weeks ago because water had gotten in and there was a terrible squeak… Considering how they’ve never been repacked after nearly a decade of muni in rain/mud/snow, is it worth repacking them, or just buying a new set and actually maintaining them? When this set dies totally, that is…

How do you pull the bearings off the axel? I looked for a bearing puller but could not find one at UDC.

You can go to your local hardware store and get a bearing puller.

Same as Evil-Nick. I’ve never repacked bearings. My bearings eventually break and that’s when I change them. I’ll try repacking my bearings on my winter wheel once the snow melts. :stuck_out_tongue:

A cheap bearing puller ($8-$12) is a really good investment.

Just remember, IMHO you don’t necessarily have to pull the bearings. I would only pull the bearings if they need to be soaked, due to a lot of rust or dirt. Most of the time, I think it would be fine to just wipe them out with a paper towel and then repack. This is what I did, and it made all of the difference in the world. Of course, as you can see in this post, there are varying opinions on this topic…pick one and go with it. All of the opinions seem to carry a good point, I think it just depends how much effort you want to put into this maintenance.

What’s the cost tradeoff of just replacing the entire bearing cartridge? Or do most set ups have a bearing cartridges that require tools? I’m runing old-school KH/Onza gear, so I pull the cranks off and the bearing cartridge slides right off the assembly.