How To bearing overhaul+crank removal (with pics)

I jsut went through my first bearing overhaul, and as I went in pretty much blindly, I figured I’d document it for all of you who never have.

I will send this link to evilewan for his FAQ’s


oh boy,same question in two threads:p

where is the pic of the mallet in use.

If you need a picture of hammering a bar…

well you showed it,people will wonder dont you think and not all people know the importance of that step.

i think you forgot a step and are afraid to admit it :wink: seriously though,you show the pic with all the tools but theres no mention of the hammer step?

the step by step looks real sweet and will be nice to link to instead of explaining over and over to forum newbies.

looking back, i did notice that I forgot to mention tapping the bar with what. thank you, i edited it. I saidi ‘tap with rubber mallet’

Thanks (I’m not going through that agian to include a mallet pic though.

Honestly though, when I get things, like a PVC pipe, and a proper bearing pulller, i will be udpating it (on my next bearing overhaul) I’ll include it then.

Bravo sofa nice and complete. now I am positive I can do this on my own(or at least with some help from pops).


im talkin about beating the cranks with the mallet not the bearing,dont you beat them on before tightning the axle nut?

I like all the pictures with Loctite in them. :slight_smile:

You should add something about pressing on the bearings. The short section of pipe (or handlebar or seatpost or conduit or whatever) needs to be the right diameter. The diameter needs to be small enough so that it is only pressing on the inner race of the bearing. If the diameter of the pipe is too large you’ll end up pressing on the bearing seal which will damage the bearing. Pressing on the outer race to press on the bearing can also damage the bearing. Only press on the inner race.

And you’re nuts to take the time to overhaul a sealed bearing. You’ve got too much time on your hands if you’re doing that. New sealed bearings are like $8 (USD) each. Much easier to just buy new ones than overhaul the used ones.

I did like the picture showing all the crud in the bearing. It really explains why bearings on a muni don’t usually last very long. :slight_smile:

there is absolutely no need to pound on your cranks to install them.

This took about 2 hours (my first time, and wiping the grease off my hands to snap the photos)

The most time consuming part is getting at the bearings, and then replacing everything.

Now that I’ve done it, overhauling the bearings would take about 20 mins total. That’s worth $20(cdn) to me :slight_smile: Especially now that I have 3 unicycles

you are wrong my friend.

can someone else take over this argument or help on this please.

as the nut tightens, it pushes the crank on. as it’s still so loose in there, you’re not really forcing anything with the nut.

I have taken off and put on 14,000 cranks on bikes and Uni’s this way. You don’t need to bang them. Feel free, of course, I just didn’t think it was necessary to include steps that aren’t needed :slight_smile:

The last time I had a crank fall off, I hadn’t checked it in about a year’s worth of MUni. My fault, I suppose

Nice write up Sofa.

I agree with John Childs about overhauling the bearings, if you shop around (i.e. beyond you can find 6203 bearings quite cheap. I can get them for $6 AUD Each, that is cheaper than one from

In relation to you using WD-40 as the degreaser, I have personally found it to be horrible stuff. It is sticky so whenever you leave it on any external surface everything ends up sticking to it, beating the point of using it in the first place. I use an Australian product called Inox instead which I find better, I am not sure of it’s availability outside of Oz though.



Your write up is outstanding. Your photos are clear and informative. Don’t listen to these weenies whining about you wasting time overhauling sealed bearings. They’re just jealous because they’re afraid to try it themselves. Whether it’s cost effective or not is an individual choice. Either way, there is a clear, thorough explanation of how to do it in the FAQ’s now. Thanks for an excellent contribution.

Ok, now it’s cool for everyone. I have a ‘if you’re tossing them, skip to…’ paragraph.

Unicycle Crank Removal and Installation/Bearing Overhaul or Replacement

I think you might be able to get away with seating the crank all the way on the taper just by using the retaining nut to tighten it down. Since the taper is greased and hopefully there is no galling on the cranks taper, the crank should slide on the taper very nicely. You can generate a lot of force to press the crank on just by tightening the retaining nut.

However, I would still feel better seating the crank on the taper by pounding on it with a block of wood and a mallet. It just feels like that would seat it better. Plus I don’t think it is best to use the retaining nut to press the crank on if you have aluminum cranks. The scalloped underside of the retaining nut might grind away more aluminum than if you had first seated the crank on the taper with a mallet and a block of wood.

I vote for first seating the crank using a block of wood and a mallet before finally tightening it all down with the retaining nut. If I don’t want to make a lot of noise I use a large heavy-duty C-clamp to press the cranks on. Doing it this way just feels like it seats the crank on the tapers better.

Of course the real answer is that Sofa shold get himself a Profile setup so he wouldn’t have to deal with this tapered crank installation dilemma.


But then I couldn’t afford the headphones needed to drown out the sound of my new $600 crank set creaking away with every pedal rotation.

Every creak would be cost me $3…no thanks!

And PS…what dilema? Jagur’s dilema about pounding cranks on?

From your photos it looks as if you are using the NK hub. This hub has held up well for me over the years and I have torqued crank arms down with the nut as I have done on bikes for years.
But after using this method once or twice with a SUZUE hub, you may remove a nut and find that you have very few threads left on the axle.
I have been pounding cranks on ever since this happened to me. The external threads on the Suzue axle just don’t seem to hold up otherwise.
I’ve gone to splined set ups on my MUni’s but will never install cranks again on my Suzue hubs without a good pounding first.

Nice write-up Sofa!

This is why I always pound the crank on rather than use the retaining nut to push the crank on the taper. I’m worried that I’ll strip the threads before the crank is fully seated - especially at the start when there’s only a few threads engaged in the nut.

I ALWAYS follow John Child’s crank installation method (grease the taper, use Loctite, etc.). I usually start the nut on the threads and snug it up. I then whack the crank with a plastic mallet - snug up the nut - whack the crank - snug the nut until the threads are completely engaged in the nut. Then I finish up by tightening the nut.

Steve Howard