How to be a bike mechanic

Years ago, I bought a Dekerf Team ST that was very well used. The fork oil was all over the outside of the fork, the fork crown was cracked, the frame probably had never been cleaned, the cables were messed up, and the wheels… The wheels had a clunk in the front – like there was a loose bearing – and a rumble in the back, which usually means a pitted cone.

And on top of that, the rear rim is very concave on the braking surface – the metal has been worn away and the brake pads will soon break right though the rim. They rim really should be replaced before it breaks.

The problem is ┬áthat they’re weird wheels. The nipples are at the hub instead of the rim. The rear is offset bigtime. Getting a new rim to fit these wheel is probably not an option.

Cane Creek WAM

Cane Creek WAM

I was pretty discouraged by all this at the time. They’re Cane Creek WAM Cronos, which was a pretty high end wheelset from the late 90’s. It really seemed dumb that they were essentially garbage.

I took them apart, and found a pretty conventional ball-and-cone arrangement on the drive side of the rear wheel. This is where ball bearings are held in place by a cone that’s threaded onto an axle. The correct preload on the bearings is achieved by tightening the cone just right. The other side of the rear wheel I couldn’t figure out. There was no place to put a wrench on it, and you couldn’t pull it off, or even pry it with a thin screwdriver.

The front was worse. I was able to remove a dust cover from one side, and that’s it. I figured then that these would probably go on a TeamCow BikeSale bike, because they were just too far gone.

Tonight, I tried again.

Cane Creek teardown

Cane Creek teardown

On the left are the bits from the front wheel – the axle (A), two cartridge bearings (B), and two dust covers (C). I pryed off one of the dust covers, like before, but tonight I thought; “I’m going to hit this with a hammer.”

You’d be amazed how often in the world of bicycle mechanics, the answer to “What do I do now?” is “Hit it with a hammer.”

One decisive strike with my rubber mallet, and the axle, bearing, and dust cover fired out of the hub. I then used a 10mm allen key to tap the dust cover off of the axle, and the bearing came with it. Which is pretty weird, but, whatever.

Finally, I put the axle back in the hub, and smacked it again with the mallet to knock the other bearing out of the hub shell.

And voila! Two new 6903RS bearings, and the wheel will be as good as new.

For the rear, I loosed the lock nut on the drive side, and began to loosen the cone, which resulted in the axle (D) backing out of the freehub body (F). This was odd – something was holding the axle in at the other side, but I didn’t know what. So, once again, mallet to the rescue.

I smacked the “cone” (H) from the non-drive side out with one hit, and discovered a cartridge bearing on that side. I removed that cone, pulled out the axle, then removed the freehub body with a 10mm allen key.

Then I gently pryed the dust cover from the non-drive side (G) off, and smacked the bearing (E) out of the hub shell with that trusty 10mm allen key. That 10mm is really the MVP of the night.

The hub cone was quite smooth actually, so it’s the cartridge bearing that will have to be replaced on the rear.

So, there you have it. It’ll be about $12 worth of bearings to make this wheelset feel like new again. At least until the rear rim’s braking surface is totally gone.

I know not everyone is willing to do this, to just poke around and see what happens. For me, that’s what being a good mechanic is. It’s not necessarily knowing what to do – because I didn’t know anything about how this wheel went together – but more knowing what not to do. Knowing how to not go too far and break something.

That, and well placed hits with a rubber mallet.

 

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