10-02-2013, 11:15 AM
no downside to harder balls.
If you look at the stress in the cups, cones and balls; you will find that the cups have the lowest stress, and the balls the highest, with the cones in the middle, but closer to the cups than the balls. The stress is a function of the radius of curvature; larger radius of curvature -> lower stress.
Some people use ceramic cartridge bearings, the vast majority of those have hard steel inner and outer races, with even harder ceramic balls. The balls still fail first. I do not recommend ceramic bearings for bicycles, the main issue being that the thermal expansion coefficient is not the same as steel (or aluminum or carbon fiber), which results in the fit changing over temperature. If you are a pro and have a pro mechanic tweaking things every time you stop for a minute - things are okay. For those of us without a full time pro mechanic following us around all the time we are biking - stay with steel on steel.
If you look at the stress in the cups, cones and balls; you will find that the cups have the lowest stress, and the balls the highest, with the cones in the middle, but closer to the cups than the balls. The stress is a function of the radius of curvature; larger radius of curvature -> lower stress.
Some people use ceramic cartridge bearings, the vast majority of those have hard steel inner and outer races, with even harder ceramic balls. The balls still fail first. I do not recommend ceramic bearings for bicycles, the main issue being that the thermal expansion coefficient is not the same as steel (or aluminum or carbon fiber), which results in the fit changing over temperature. If you are a pro and have a pro mechanic tweaking things every time you stop for a minute - things are okay. For those of us without a full time pro mechanic following us around all the time we are biking - stay with steel on steel.
Nigel
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