So I went riding in the mud today, and while I had a blast, now my bearings make a crunching sound when I turn them. Is that bad? :s Anyway, I know nothing about bearings, and was wondering:
Can they be dissasembled and cleaned, or should I get new ones, or should I just keep riding on them?
Does this mean I don’t have “sealed” bearings?
Should I get sealed bearings for mud/snow/otherwise-wet-and-dirty riding?
How do I know what size to get (I have a Suzue hub and Yuni frame)?
Tom gave you a link to a thread that will tell you more than you want to know about replacing bearings.
Replacement bearings are $6 each for your uni at unicycle.com. Kovachi 40-mm Sealed Bearing
For a unicycle that is used outdoors get the rubber sealed bearings. For a freestyle unicycle that is used indoors get the metal sealed bearings. The metal sealed bearings should have less friction (and less rolling resistance), but the metal seal is more prone to getting dented or damaged. Thus the metal sealed bearings are not a good choice for a muni.
All unicycles come with sealed bearings (well, except for the very first batch of Cokers) so you’ve got sealed bearings on your muni. But sealed bearings don’t seal completely. If the bearings sealed completely they would have so much friction that no one would want to use them on a unicycle. The seal is just a simple barrier. Dirt and water can easily work their way inside a sealed bearing.
I typically get about a years use out of a set of bearings on my muni before I start to notice degraded bearing performance. This is, of course, highly dependent on how often I ride and how wet and dirty the conditions are. If you ride in an area with a lot of fine sand you could get less than a years use from a set of bearings. If you like to ride through streams you could get less than a years use from a set of bearings. If you ride in good conditions that aren’t overly dirty, dusty, sandy or wet, you could get many years use from a set of bearings. It all depends.
If you aren’t comfortable replacing the bearings yourself you can have a local bike shop do it. But order the bearings from unicycle.com rather than letting the bike shop order them. It is very very unlikely that the bike shop will be able to get bearings for less than $6 each and very likely that they will be quite a bit more than $6 each. Bike shops should be familiar with pressing bearings in to fancy suspension MTB frames so they should be able to deal with removing the old bearings from a unicycle hub and pressing new bearings on the hub. But do request that they Loctite the bearings on to the hub cause that is a step that they likely would not do unless you ask them to.
I made this up last year (more playing with my new camera than anything)
I’ve redone it several times, so on my fleet of uni’s I have saved $20-30 worth of bearings or so.
I have also ridden with bearins that were so stuck I could ride the unicycle fine, without any notice of bearing friction, however, I couldn’t walk the unicycle down the trail, I had to carry it, the wheel would not turn on it’s own…this is what caused the initial regreasing, you can see all the dirt and crap in there.
The convenience of taking this few minutes of work outweighs the inconvenience of ordering, for me.
Thanks for the tips (and links to tips, Tom ). I’m going to order a couple of new rubber-sealed bearings tonight. The existing bearings appear to be metal-sealed. The next couple of months in Denver are usually pretty wet/snowy, and right now I seem to have the choice of riding in snow and mud or on boring flat sidewalks so hopefully the rubber seals will help.
). I’m going to order a couple of new rubber-sealed bearings tonight. The existing bearings appear to be metal-sealed. The next couple of months in Denver are usually pretty wet/snowy, and right now I seem to have the choice of riding in snow and mud or on boring flat sidewalks 
so hopefully the rubber seals will help.