Join Date: Nov 2000
Location: New Orleans, LA
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Overhauling cup and cone (still the most common) hub bearings was my first "real" bicycle mechanics endeavor. I think it is an excellent way to start building competence and confidence. There's not much risk of doing any permanent damage. A couple of suggestions that apply to this and other jobs.
1. Study how to do the job. I really suggest getting a good book (search for threads on this) or use the Park website and print out the pages. Read it over a few times.
2. GET THE RIGHT TOOLS. You really need to get a set of cone wrenches. They are thin to fit the narrow flats. You don't have to get the very best. Nashbar, Lifu, Performance are fine. The double ended "trail" versions are fine for home use.
One thing I people have a little trouble with is proper tightening of lock nuts. You finger tighten the cone then back it off just a touch. They should be close enough that their is not side to side play in the axle, but not tight enough that you feel resistance when spinning the wheel. Then hold the cone in that position while you tighten the lock nut against it. You have to use two wrenches so that you are turning the two nuts against each other not just screwing the locknut tight by itself. If you just turn the locknut by itself it will also turn the cone, and the two will not really be locked so the cone will loosen pretty quickly. Also be aware that as you tighten the screw the locknut down even while holding the cone still, the axle may try to turn and will wind up changing your adjustment a bit. Sometimes it may take several tries to get the final tension just right. You also need to allow just a bit of slack that will be taken up when the quick release is tightened. All this should be in the instructions you use. I mainly wanted to stress that the locknut and cone need to be turned AGAINST each other for proper lockup.
Once you have done cup and cone hubs the same principles apply to cup and cone bottom brackets and headsets so your have actually learned most of what you need to know for all three. What a deal!
Oh, even top grade 25 bearings are really cheap. Many people go ahead and replace the bearings with grade 25.
Again - GET THE RIGHT TOOLS! There are only a few special tools needed, and they don't cost that much - cone wrenches for hubs, crank puller, pin spanner and bb lockring tools for bottom brackets, headset wrench for headsets. Buy them as you need them.
If it ain't broke, mess with it anyway!