Replacing cartridge wheel bearings
4.15.02 by Dan Empfield
(www.slowtwitch.com)

Fulfilling a promise I made to someone on our Forum a couple of weeks ago, here are instructions on how to replace the bearings in your race wheels (or any wheels, or generally any pressed-in cartridge bearings you'll need to replace).

I should say at the outset, though, that people get way too hung up about bearings. you can buy ridiculously precise (and expensive) bearings, and the ridiculous part comes in when you realize that much of what you pay for is, for example, the "roundness" of the outside diameter. Getting the O.D. of the bearing excruciatingly round is silly when you realize that the I.D. of the hub isn't nearly so precisely machined.

All that said, sometimes bearings need to be replaced, and about the best thing you can say about many of these replacement bearings is that certain bicycle shop suppliers buy them packed to the gills with lightweight grease. Otherwise, they're the same bearings made for the rest of industry.

For the purposes of demonstration I replaced a set of front wheel bearings in my HED3s. The axle comes out of the wheel by virtue of its two piece threaded design, which is installed after the bearings are both pressed in and taken out before you can get the bearings out again. The locknuts were removed using a pair of 17mm open end (or box end) wrenches (pictured above left), and the axle comes apart as is shown above right.

That leaves you with an axle-less wheel, which you can see at left. Now, how do you get these bearings out? There are a variety of tools for this maneuver, and they range in price from $5 to way over $100. Given the choice, I prefer the $5 tool and that's what I used.

This bearing puller looks like a little tiny pair of tongs that one might use to pick up itty bitty ice cubes to put in one's martini glass. You squeeze the tongs together and insert them through the bearing. The ends of the tongs have lips that lay over the inside of the bearing. The idea is to then insert a peg of some sort into the other end of the hub, the peg now resting on the bearing puller's lips, and then whack it with a hammer. Out pops the bearing.

This doesn't work exactly as advertised because the lips on the tong-like bearing pullers lose traction on the inside bearing surface and shoot back out the wheel when you whack it. So instead of sticking a round peg through the other side of the wheel you stick a flathead screwdriver in there and this wedges itself inbetween the bearing puller's tongs. You whack that one or twice and presto, out shoots the bearing.

One thing. When you're banging (nicely) on the end of the screwdriver, you do need to have the hub shell supported, and of course this must be done in a way that will allow room for the bearing to be pressed out. I use an appropriately-sized crown race installer (that blue thing under the wheel at left). But you could use anything round with the right size hole in it.

Once the bearing pops out you can see what the whole bearing-plus-bearing-puller arrangement looks like (at right). Popping the other side out is easy, you don't have to use the bearing puller to do so but using it is as easy as anything else. Once that is done you've got an empty hubshell, as is shown at left. Now you've only got to install the new bearings and then the axle.

As an aside, I might mention that you ought not to mess around pulling and reinstalling your bearings, which is to say you ought to only remove them if you have a new set you intend to install. The act of removing these bearings can damage them, and so I wouldn't recommend removing them just for the entertainment value, or to see if they're damaged. Have another set handy when you do so.

Now you're ready to install the new bearings and, no, you don't need an arbor press. Even if you had one it wouldn't do you any good, because that's a great thing to have if you're just installing bearings into a hub, but you'll never be able to fit a whole wheel into an arbor press. It's just as easy to bang them in with a rubber mallet. The best thing, though, is to bang on the outside race, not on the flat of the bearing. You just need something round and the right size to do the trick. My crown race installer is not the right size for this—its diameter is too big—but something in the neighborhood of a 20mm socket works quite nicely (or perhaps 7/8"). To do it right you'll need two, one above the bearing you're whacking, and the other below the botton bearing (You may as well install both bearings at the same time).

Then reinstall the axle and you're all set to go.