36-er "road feel" - something's not right

[tomblackwood]

Hoping for some troubleshooting advice on a situation I have with my ungeared Hunter 36. It has always ridden super-smooth, but last night after doing about 15 miles on a cinder track, I noticed a little bumpy feel, almost like a click, once I got back on pavement. My first thought was I had lodged a big pebble in my Nightrider tire, and in fact there were many. I cleaned them all out, but the feeling persisted. Closest way I can describe it is what it felt like when I first put on a new tire, and it hadn't yet seated completely all the way around the rim. Tonight I tried to tune in more to it. If my hands are at my side, it's too subtle to feel through my butt. When I put both hands on my handle, I can feel the clicking, definitely correllated to my rotation speed. It feels like two clicks per full rotation of the wheel.

First thought was the Stockton wheel, but all the spokes are still outrageously taught, and the wheel is true. But I notice that when I hold the uni up and spin the wheel, it feels a "little rough" through the handle. The wheel spins fine...no slowing down like when you over-tighten the bearing holders. Just feels rough. Seat is plenty tight, no looseness in the rail adapter, GB handle is cranked on, no play there. Tried to pull the cranks every which way by hand, but they're torqued on solid. Pedals seem to spin fine.

I'm paranoid because I recently had a total pedal failure on my 29-er, and went down pretty hard.

My theory is that it is a bearing problem, either the wheel bearings or a pedal bearing. So questions:

• Anything else come to mind as a possible source?
• The wheel bearings only have about 6,000 miles. Is that within mileage where problems start to surface?
• I can test for the pedals easy enough. If a new set doesn't fix the issue, is there any way to confirm it's the bearings without pulling the cranks and installing a new set?

Thanks for thoughts...

[Max_Dingemans]

I'd try pulling the wheel off the frame to see what spinning the bearings by hand feels like. It might not help, but it's possible you'll feel/see something obvious.

[tholub]

If you can feel it when you're not loading the uni, I agree that it's very likely to be a bearing, and if you can feel it when you're not moving the pedals, it's very likely to be the wheel bearing.

Other possibilities are more significant; a crack in the frame or the hub flange or something like that. But my money would be on the bearings.

[bungeejoe]

Do you have free space between the bearing holders and the crank arms
as the wheel is rotated?

[capuni]

I experienced a similar clicking issue at RTL. For me it was the wheel bearings. I kept riding because I couldn't figure out what the problem was. Going up a hill I heard what I thought was a spoke breaking. Turns out the bearing cage itself split under torque.

Darren Bedford was able to help me out. He said I was lucky the bearings didn't seize and throw me off. I had less than 3,000 miles on the wheel.

If the bearings are bad, you'll want to get them off before the cage cracks. Once that happens there's a good chance you'll destroy the hub trying to remove the bearings.

[goldenchickenreincarnated]

Did you check the wheel if it is true radially?

[feel the light]

Every tire change, I turn the inner race by finger. You will have to do the outer race instead. On a motorcycle I would replace any bearing that had even the slightest catch or any roughness. 8 $ is small change to avoid crashing or getting stuck on the cycle. You would think they would last forever on a uni, as 50, 000 miles on a motorcycle is average. However, we tend to bang them sideways, so actually ours won't go that far.

So anyway, just take the wheel off and move the outer race with your finger. If you can't feel anything but smooth, the bearing is fine. I does sound like bearing trouble though.

[skrobo]

you turn at speed on a motorcycle, i'm guessing that puts significantly more sideways force on the bearings.

now, i had the same problem on a trials cycle, turned out to be the frame/bearing clamp once, and the un-oiled bearing another time.

if you took the frame off and put it back on ... it is the bearing.

[saskatchewanian]

I had a similar problem a few years ago with my 36er.

It turned out to be a slightly loose crank arm. I could not tell what was wrong with it until it got significantly worse than when I first noticed it. I did the same push pull and wiggle thing to see if they were loose and also felt nothing but you can put way more pressure on your cranks riding than you can by hand.

I have also had pedals deteriorate which feels similar but i was able to feel the looseness of the pedal bearings when checking for play.

[tmoyer]

I've also had play develop in the connection between the axle and the hub, which feels similar to what you're describing. That play is hard to feel if you're pulling on the crank the way you normally would to check for loose cranks. To feel it, you need to jam the wheel against something so it can't roll and then pull the crank hard up and down. Then you can feel the little tick-tick as it moves back and forth, even though the cranks are completely tight on the axle.

[Peripatet]

Originally Posted by tmoyer

I've also had play develop in the connection between the axle and the hub, which feels similar to what you're describing. That play is hard to feel if you're pulling on the crank the way you normally would to check for loose cranks. To feel it, you need to jam the wheel against something so it can't roll and then pull the crank hard up and down. Then you can feel the little tick-tick as it moves back and forth, even though the cranks are completely tight on the axle.

Agreed. I have one square taper hub in my stable that gets this issue every couple months or so. Chalking the wheel and really yanking the cranks will definitely show you the offending piece.

[tomblackwood]

Great suggestions everyone! Great example of the wealth of expertise in the unicycling community. I ended up trying a few things, starting with the easiest "chock the wheel and pull hard on the cranks", then moving on. Problem has been identified, and the winners are:

Originally Posted by Max_Dingemans

I'd try pulling the wheel off the frame to see what spinning the bearings by hand feels like. It's possible you'll feel/see something obvious.

Originally Posted by tholub

But my money would be on the bearings.

After pulling on the cranks and deciding the pedal-spin didn't feel like the issue, I tried just spinning the wheel again. This time it felt even rougher than the last time I did it, which was before my last ride. So I pulled the wheel from the frame, and in spinning the wheel bearings it was quite obvious one of them was shot. Feels, sounds, spins as if there's no lube at all left inside. Interestingly, the outside of the bearing had one section...just under a half inch long...that was really rusty. It corresponded to some rust inside the bearing holder. I had greased the outside of these guys and the insides of the bearing holder quite thoroughly last time I had the wheel off, which makes me wonder whether the bearing holders are not perfectly half-circular, allowing for a small place where moisture can get in and cause corrosion.

So given I've never replaced wheel bearings on a 36-er before, I have two more questions before I start:

1) Any trick to it? Seems straightforward, pull the cranks, pop the old bearings off, press the new ones on, re-install the cranks. No spacers or anything like on profile hubs. Anything I'm missing?

2) Anyone else have that rust situation? Makes me wonder whether I should regularly pull the wheel and rotate slightly the bearings in the bearing holders, just to keep one section from spending too much time underneath that imperfect section of the bearing holder.

Thoughts appreciated...thanks again for all the great advice above.

[ħǻřрέŗ]

Originally Posted by tomblackwood

So given I've never replaced wheel bearings on a 36-er before, I have two more questions before I start:

1) Any trick to it? Seems straightforward, pull the cranks, pop the old bearings off, press the new ones on, re-install the cranks. No spacers or anything like on profile hubs. Anything I'm missing?

2) Anyone else have that rust situation? Makes me wonder whether I should regularly pull the wheel and rotate slightly the bearings in the bearing holders, just to keep one section from spending too much time underneath that imperfect section of the bearing holder.

Thoughts appreciated...thanks again for all the great advice above.

Having a bearing puller makes this task a snap. I have some at work but you may want to just buy one because they're cheap. The bearing puller will pull on the outer race and stress the bearing in a way that you would not want to reuse it. These are cheap automotive bearings you should be able to get at an auto parts store or McMaster Carr online. The bearing puller as well.

You can tap bearings on with a pipe the right size to engage the inner race and clear the axle. This will NOT stress the bearing. An arbor press is much easier but that's only useful if the hub is off of the wheel. Finding an arbor press to span an 18" radius wheel would be dicey.

My guess is that it has nothing to do with rust but that one of the balls has chipped or cracked. Your bearings will never make as much annoying noise as the rider of your unicycle.

[tomblackwood]

Originally Posted by ħǻřрέŗ

Having a bearing puller makes this task a snap. I have some at work but you may want to just buy one because they're cheap. These are cheap automotive bearings you should be able to get at an auto parts store or McMaster Carr online. The bearing puller as well. You can tap bearings on with a pipe the right size to engage the inner race and clear the axle.

Thanks Greg. I have a back-up set of the bearings, but none of the other stuff. I'll try a local auto-parts store tomorrow to try to find the bearing puller. If I can't find one I may come whining, begging to visit you at work. The MS ride is in a week so I'm on tight timeline to get it fixed and tested. On the pipe part, would the right size pvc be doable? I'm assuming that will be the easiest to find and cut at a local hardware store.

[ħǻřрέŗ]

Originally Posted by tomblackwood

Thanks Greg. I have a back-up set of the bearings, but none of the other stuff. I'll try a local auto-parts store tomorrow to try to find the bearing puller. If I can't find one I may come whining, begging to visit you at work. The MS ride is in a week so I'm on tight timeline to get it fixed and tested. On the pipe part, would the right size pvc be doable? I'm assuming that will be the easiest to find and cut at a local hardware store.

PVC will work fine to tap the bearings onto the axle. Back the bottom side of the axle with a block of wood so you don't damage it. I'm not going to work Friday but we could do it any time from Friday evening through Monday which is a holiday if you can't get what you need. I'll probably go in Monday evening to pump out the van de Graaff anyway.