'Grinding' bearings?

Hey everyone!

I’ve been riding a couple of months now, I’m loving it! However I’ve hit upon a technical issue.

Essentially, every now and then, my wheel becomes super-stiff, and it feels like things are grinding round the pedals… I know that’s not much to go off, but I have (more than once) stripped the bottom-end of the Uni down, cleaned it all out, re-oiled and rebuilt, and it seems to stop for a bit, but then it’s back 10 minutes later.

This weird little issue is seriously inhibiting my enjoyment of the sport, because I’ll be halfway round a 7-mile circuit and it’ll suddenly become way more difficult to pedal, causing things like hills and rough terrain I’d usually speed-power over to be impossible or at least significantly more difficult and tiring!

At first I thought it’s dust getting into my bearings, as my usual riding routes are either very dusty, very muddy or generally messy. But cleaning everything I can reach doesn’t seem to fix much.

Is this a bad sign ? :thinking: I’m slightly worried I’ll be riding along and my bearings will all of a sudden give way… The Uni is just a cheapo eBay special, though I’ve replaced a few parts on it the bearings remain original (As does the rest of the wheel/hub assembly)

My dad thinks the bearings might be wearing out… But I’ve not had it THAT long. Do Unicycle bearings usually wear out this fast? Considering all the weight is on one wheel instead of distributed between two…

I’m thinking about buying a more expensive Uni soon, so also want to know if this is something I’m going to have to get used to, like replacing popped inner tubes :stuck_out_tongue:

I had bearing problems similar to yours a little while back. I was hosing down the unicycle regularly after riding in muddy trails. Water got into the bearings, corroding them. I ordered new bearings and replaced them - voila!


+1 on water getting in.
Also, if you over tighten the caps it can cause premature bearing wear.

Both of those make sense - With it being a cheap Uni I figured I’d have to tighten them extra-tight. And, I’ve been riding it through massive puddles and mud recently!

Thanks both! :smiley:

Seems like your bearing caps are too tight. Loosen each cap bolt 1/4 turn approx. before your next cycle.

Done and done :slight_smile:

Won’t be riding again till tomorrow :stuck_out_tongue:


Small mistake, big consequences. Even that “a little bit tighter then necessary” can make a big difference on your progress in riding and your bearings life span.
But changing the bearings is easy to do and won’t cost you a fortune.



I’ve loosened them a bit now, and shall be going out later today :slight_smile:

Thanks everyone for the tech support! Really appreciated :smiley:

Quick update, I’ve loosened my bearing caps a bit, and tried riding my usual daily 7 miles.

I also re-greased the bearings after giving them a good clean-out, and just generally gave the whole thing a clean.

Unfortunately, nothing’s improved, and in fact it’s getting steadily worse, so I think it’s new bearings time!

Your bearings may be damaged. I never do any maintenance on my bearings and I never have any problems with them. I think bearings are lubricated for life so I wouldn’t go spraying anything in there or oiling for fear of diluting or dissolving the existing lubrication.

To check for correct bearing cap tightness, turn the unicycle upside down and spin the wheel with your hand. The wheel should complete about eight revolutions before coming to halt.

To check the bearings, remove the bearing caps and spin the wheel slowly with your finger tip on the bearing. If the bearing is good you’ll feel nothing. If the bearing is damaged you might feel a rough movement coming from the bearing.

Hope this helps. Let me know how you get on.

Yeah the original bearing-lubrication looked like it’d dissolved/disappeared/been replaced by water, hence why I re-greased them (My dad owns a bike shop, so we have a plentiful supply of bearing grease!)

The bearings don’t feel bad when doing your last test, so I guess that’s a good sign.

The bearing CAPS however… I think this shows how cheaply-made these eBay Uni’s are - The two pieces of metal are touching far too early, and I think it’s this that’s causing my issues. It’s as though the gap for the bearings to sit in is too big, and so the bearings can move about in their seat a bit too much (I actually tested this by screwing them as tight as I could, and trying to wiggle the wheel around… There was FAR too much give in the wheel movement…)

I’m thinking two options - grind down the bearing caps so they go a bit tighter, or pack them with rubber to provide a snug yet not ‘too tight’ fit. Does this sound reasonable? :thinking:

you could try shimming them with pieces of pop can as well.

You could try the rubber. Or try Killian’s suggestion which is what most unicyclists do. You can also buy shims from unicycle.com. I wouldn’t use a grinder unless all other options fail.

I had to shim my 29er’s frame after I bent it (or noticed it wasn’t straight a year later :roll_eyes: ) A few strips of pop can went a long way.

Are you certain it’s the wheel bearings? It sounds like they probably are but I’ve had problems with pedal bearings as well so it might be worth checking into.