My crank is touching my frame, what do I do.

This is the good crank, the one without the problem

this is the bad cranks, as you can see there is no clearance

I think I might just have to take my frame off and reposition it, but is it more serious than that?

Still 3.jpeg

Still 4.jpeg

good crank

bad crank, the freemoving thing between that crank and the wheel doesn’t spin so freely

Do you have all the spacers on, I can’t see the one on the bad side.

yeah, its on

Take the frame off and picture the hub with the cranks and everything as is alright. That should help.

I had that same problem awhile back, the bearing kept slipping so the frame was pushed out till it was rubbing on the crank. I have no idea why it happened and I don’t really know how to fix it. I tried replacing the bearings but that didn’t help, the new ones slipped just like before. I assume it’s a problem with the axle but I really don’t know

ine started doind that… i just road till it ground away

Sounds like spacers were your porblem. There should be no room to slip. I can take a pic of my wheel if anybody wants. But, the bearing should be held in place by 2 spacers, one on each side. This should keep it in that same spot. I ride a hub where the bearings fall off when the cranks are off but with the spacers and cranks on I haven’t had a problem.

Are those square taper cranks or splined?

they are the standard cranks on nimbus 20" Trials Cycles

Then it’s ISIS splined. There should be a spacer between the bearing and the crank.

I know, the bearing is moving the other way.

Picture it this way, the bearings are so far apart, the frame wont even rest on them

Time for a KH

Maybe the spacers at mixed up. I know on the kh has 2 sets of bearing, 2 different sizes.

As I said, if you take the frame off and picture it that would greatly help. When was this uni bought? Do you recall an option for uprading the cranks to something like kh on the page?

That is ISIS splined and you are missing the spacer on the bad side. See how you can see that bit of black on the good side? Thats the metal spacer, there should be one on the other side as well but it isn’t there.

We know its ISIS because it has the machined bearing holders. The bolt threads into the frame legs whereas on the older non ISIS models there was a nut and washer that would have to be on the top. The ones for cotterless hubs had 40mm non machined holders.

The same problem would happen with a KH uni if it was missing a spacer. Theres nothing wrong with this unicycle so theres no need to upgrade anything, you just need a spacer on the other side so it doesnt rub. If you just got this uni recently and haven’t removed the cranks at all then you definitely need to call up UDC and tell them they shipped it without one of the crank spacers.

I’ve been having the same problem with my Nimbus 29" with ISIS hub. Mine came with a spacer between the hub and the bearing, but not with one between the crank and the bearing. That looks like the same setup as this one. The problem was my bearings were slipping on the shaft. I had to pull the cranks and bearings. I then cleaned the bearings and put Loctite on the inside of the bearing race and put it all back together. I waited about 12 hours for the Loctite to set up and I haven’t had a problem since. I’ve found other threads about this problem using “slipping bearings” as the search words. There was a really good thread explaining everything that needed to be done.

I think my unicycle may have been shipped without spacers. The amount of space from the bearing to the frame is different on both sides. Is this odd? Also could someone post a pic of what it should look like with the spacers

Well, as been mentioned theres two sets of bearings on either side. Theres spacers between the hub flanges and the bearings and also between the bearings and the crank.

Heres what it looks like with no spacer between the crank and bearing which would cause what some people are describing. Notice the gap between the bearing and the crank where you can see the toothed splines of the hub:

In the closeup of the hub in this next picture you can see the black metal spacer up against the bearing, thats where the spacer should be and your cranks should be up right against it so that you can’t see a gap like in the picture above. Notice that you can’t see the spacer against the bearing in the first picture I posted.

How important are these spaces. I dont have the ones that go between the bearing and the cranks. Should they be there and should I contact UDC about it? btw I have a Nimbus x Street.

I’m not an ISIS expert, but it seems to me like spacers are wrong in this application. The ISIS spline is tapered, which means the crank should be held on by its own friction on the spline, and the pressure of the crank bolt. If the crank hits a spacer before it is sufficiently tight on the spline, it won’t be tight enough and will work itself loose. Similarly, the bearing should be held on the axle by its own press fit, not by being torqued down by the ISIS crank+spacer.

Use Loctite green sleeve retainer in between the bearing and the axle, and press the bearing all the way up against the hub. Let it sit for 24 hours before riding.