I got really gross bearings on my 16er, haven’t ever been cleaned. (5 years). How to clean without removing from hub?
What is the issue? Just use a rag or paper towel and wipe away the grime. Any cleaner that can be used against grease if necessary, it aint rocket science.
Okay, I just didn’t know if there was some special grease thing to clean it. Never done this before.
Afterwards tighten the screws more carefully than I did when I cracked the bearing shell of my first uni.
Bearings themselves are extremely cheap, I’d say replacing is better than cleaning. But they are certainly shrunk or at least pressed/hammered on the shaft. So you require a bearing puller. Not a fun repair. So as suggested a paper towel is the easiest/safest way.
There’s dirt and grime on the outside of the bearings which is cosmetic. However, with the wheel removed from the frame you can more closely examine the bearings. Check for side-to-side play and gritty/grabby feel when rotated. Those are signs that the insides need to be cleaned and re-greased or whole bearing unit replaced. Cleaning the internals is best done with the bearings removed.
I removed the grime with a paper towel, but it is still rusty. I’m also not sure it is supposed to stay in place inside the frame. The bearings never have spun inside the frame, rather and internal spinning. I am turning them with my fingers, and it moves, but is inconsistent and doesn’t fully roll smoothly. Bearings are pretty cheap though, so I’m leaning towards just getting new ones. If so, would I need a special tool?
I agree with just buying new. You’ll need a bearing puller tool regardless of whether you attempt to clean the internals or just replace with new.
Here’s one such tool: Buy Nimbus Unicycle Bearing Puller Online
Would a bike shop have one of these?
A bike shop would probably one but I doubt for sale.
I purchased a cheap bearing puller from Harbor Freight and it worked for me. I just searched but could not find it. Probably discontinued.
I bought one at a flea market. Needs to be a rather small one, if it‘s one of the three arms type: https://5.imimg.com/data5/YH/MV/MY-42173824/mechanical-bearing-puller-500x500.jpg - maybe there‘s even some grinding needed if the arms are too thick. The two arms type as sold by unicycle.com is certainly better, but the three arms type seems to be more wide spread, so more easily available second hand (and cheap).
I just replaced the bearings on my Club 26" uni yesterday, actually 
After a couple years of riding (and occasionally being left out in the snow, ridden through water, etc.) the bearings started to sound dry and one of them was no longer rolling smoothly.
I think for the whole job I used
- An 8mm allen key for the crank bolts
- A crank puller (Bearings won’t come off without pulling the cranks of course)
- A 15mm wrench for operating the crank puller (The type I used anyway)
- A bearing puller (I used a Nimbus puller but any sort of bearing puller that can grasp the bearing well will work. Just be sure to protect the crank interface when pulling)
- A 14mm socket/wrench to operate the bearing puller (For the Nimbus, may be different for other pullers)
- I used a deep well impact socket to hammer the new bearings back on. I found the smallest one that would fit over the spindle (A 17mm socket in my case), lightly greased the surface, and hammered the bearings on using the socket to drive the bearings in until they went up against the stops on the hub
- A torque wrench and a T50 Torx bit to torque the crank bolts when reinstalling the cranks (Would be more ideal to use a proper Allen bit but the T50 is all I have lying around to use with the torque wrench, works good enough)
No need to hammer. Just push the bearing on with the crank and spacer(s). Maybe have to start with one spacer, then, before the crank is firmly mounted, remove the crank and add the second spacer. Instead of a crank you could also use a big washer, if you have a fitting one available.
If it’s not a Schlumpf (or some other exotic hub) there’s in my experience no need for a torque wrench to mount the cranks. I just tighten them firmly with a ~ 8cm long allen key. Neither did a crank come off, nor did I damage any threads, so far.
I usually take the bearings outside and spray them liberally with brake cleaner to remove all the old grease in any gritty stuff that’s in there. Then I’ll shoot a few sprays of WD-40. After wiping down each bearing with a clean microfiber cloth, I pack the bearings with fresh lithium grease, push the seals back into place, and reinstall.
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The lack of spacers on a square taper hub/crank will make that difficult. (Works for Isis or q-axle though).
True. I‘m (too) used to ISIS…
Yeah that reminds me when I bent my cranklifter and went to the bikeshop to get a new one and ask them to remove the crank for me. I told them it was the universal size of crank lifter for unicycles. When I stepped out of the store, I remembered that I was spoiled with ISIS cranks.
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I always try to clean the bearings before replacing them. Most of the time it works. It’s much easier if you get them of the hub, so you can remove the plastic covers on the side.
With hot water, soap and a toothbrush you can get rid of the most old grease. After that i will put it in the gasoline to get the last removed.
Let it dry properly and then put new bearing grease in it. With this kind of maintenance you can save a lot of bearings.
You will need a crank extractor, bearing puller and sometimes a tool to get the bearing back on.
I understand all the cleaning tendency in case you don’t have the tools to replace bearings. 6203 2RS cost like 15,49€/18,23 US-Dollar per 10pcs including shipping. Their size is 17x40x12, use the shims in case 17x42x12 appears to be expensive.
We are talking about a bit more than 3€/3$ to have it all new.
Well actually, the bearings I need are only $14, but I do also need the tools, which add up.
https://www.harborfreight.com/3-jaw-puller-set-3-piece-63953.html
These will do the trick, I have this same set. A crank puller would also be a good investment. There are Lots for sale on Amazon that are very inexpensive just make sure you get the right one, the pullers for isis and square tapers are different. The tools are an investment you will have for the long haul if you take care of them. I assume you will be riding for many years to come.