Does any body know how to get main cap bearings off the axle?
I think you need some bearing pullers.
I found a pic but don’t know if there’re for bikes/unis.
You’re probably best waiting for someone to post who knows more about it.
I’m interested in this as I’m sure my bearings will need replacing soon, is there a way to do it without pullers?
unicycle.com sell various versions:
DM sell their version in the UK: http://www.unicycle.co.uk/spares_and_tools.htm
but there’s probably cheaper alternatives available…
You can get them at an auto parts store. I ended up buying mine
through uni.com just because it was convenient when I had to order something else.
They are really easy to use. But you better know how to put the new ones on before you take the old ones off, of course.
If you have Profile cranks get the Evercraft bearing puller that unicycle.com sells
The Evercraft also works well for pulling off Profile cranks. Here is a thread with pictures showing how the Evercraft tool can be used to pull off Profile cranks.
If you have Profile cranks get the Evercraft so you can also use the tool to pull off your cranks. If you don’t have Profile cranks then the type of bearing puller that onewheeldave posted a picture of will work very well for pulling off bearings.
These bearing pullers are actually automotive tools designed for pulling off power steering pulleys, water pump pulleys, gears, etc. You can find them at your local auto parts store.
When it comes time to press on new bearings be careful that you don’t end up damaging the bearing as you press it on. If you put pressure on the bearing seal as you press on the bearing you can damage the bearing to the point that it won’t spin smoothly. When pushing the new bearing on you want to press only on the inner race of the bearing. Use a short piece of pipe, seatpost, or conduit that is the same diameter as the inner race of the bearing. A short section of a 22.2mm unicycle seatpost can work well for this. Use a hammer and the short piece of pipe to tap the bearing on the hub.
The new bearing should spin smoothly. If the new bearing is rough and doesn’t spin smoothly then it may have been damaged in the process of pressing it on.
> Does any body know how to get main cap bearings off the axle?
The correct way is to use a bearing puller, but it’s quite doable using
a rubber mallet, a chisel and a 10" monkey wrench (or any length of
metal of that sort of size that’s not going to bend too easily). This
is how I did it when I changed the bearings on my Coker.
I’m assuming you’ve got a bog standard square tapered axle for
cotterless cranks. Lay the wrench across the wheel alongside one face
of the axle. Place the point of the chisel almost against the axle
under the bearings, with the bevelled side down. The chisel will be
radial to the wheel and will cross the wrench at 90 degrees. The chisel
is going to act as a lever with the wrench serving as the fulcrum.
Hold the handle of the chisel and give the end of the handle a couple of
good whacks with the mallet (downwards, so that the point of the chisel
pushes up against the bearings, not inwards towards the axle!).
Remove the tools, rotate the wheel through 90 degrees and repeat. Keep
doing this until the bearings come off.
One obvious danger is that you may bend spokes - I haven’t had this
happen, but it’s a good reason to be careful how you position the
wrench. You don’t want the chisel to actually touch the axle, because
you don’t want to take a chance on shaving off any metal, but it has to
be close. And I wouldn’t recommend this technique if you want to reuse
the bearings, though you’d probably be OK.
Danny Colyer (remove safety to reply) ( http://www.juggler.net/danny )
Recumbent cycle page: http://www.speedy5.freeserve.co.uk/recumbents/
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