Thread: Wheel Bearings
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Old 05-04-05, 02:52 PM   #7
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Join Date: Apr 2005
Location: Northern CA
Bikes: Cannondale tandems: '92 Road, '97 Mtn. Mongoose 10.9 Ti, Kelly Deluxe, Tommaso Chorus, Cdale MT2000, Schwinn Deluxe Cruiser, Torker Unicycle, among others.
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Don't mean to nit pick here, but the previous long post was a bit misleading.

The axle has the following components:

Outer locknut, washer(s) and/or spacer(s), and cone on each side. The "race" is the surface the ball bearings ride on that's press-fit into the hubshell. In most cases the race cannot be replaced. But it turns out that the races are very rarely damaged. It's the cones that get pitted first. If the cone surface is pitted, replace it. No need to go to all the trouble of overhaul if you're not going to replace worn parts. Pitted cones will continue to deteriorate.
Do not inspect the ball bearings. Count 'em so you know how many to buy, toss all but one and take it to LBS for correct sizing (even though rear hubs are almost always 1/4"). Purchase new grade 25 (or better) bearings. Never reuse old ball bearings. You cannot see imperfections in used bearings. Plus, buying grade 25 or better will improve the smoothness and durability of the hub.
Adjustment is the hard part. Rotating the cone on the axle provides the proper bearing pre-load. The locknut holds the cone and its adjustment in place. Notice, however, that tightening the locknut changes the bearing adjustment - it makes the bearing a bit tighter. The best way to adjust I've found is to lock one cone and locknut tightly in place on the axle (usually the drive side on freehubs). Clamp this locked-down locknut in a vise (or the axle in an axle vise if you're lucky to have one), and make all adjustments on the non-drive side. You want to result with an adjustment that is not loose - no side-to-side play in the bearing with the wheel on the bike. This is crucial. The rear hub adjustment can be checked with the wheel off the bike. Axle should rotate as smoothly as possible but with NO PLAY. Cup and cone bearings require there be no play, even if the bearing feels a bit "grainy" when adjusted to the point where the play disappears.
The front hub presents a different problem. When you properly close a front quick release, you compress the front axle, cones and locknuts. So a proper hub adjustment off the bike will be too tight on the bike. The ideal adjustment is a little play in the front hub, but as you close the QR, the play disappears. The result is a smooth-operating front hub that will last years. (Most bikes off the shelf have front hubs adjusted too tight, and they exhibit premature wear.)
The grease provides smooth operation and corrosion resistance. Bull Shot is my favorite. Grease all threads on the axle for ease of adjustment and future disassembly and additional rust prevention.
Good luck!
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