Update on radial/deep groove vs angular contact bottom bracket
03-06-17, 02:07 PM
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Update on radial/deep groove vs angular contact bottom bracket
Using a separate thread to report back on this issue. I noted that some firms offered both deep groove and angular contact (AC) bearings for my BB90 bottom bracket. I started a post and asked which is best. Got responses back, summarized as
1) Use what came with the bike
2) The Hollowtech crank and the little "torque thumbscrew" aren't rigid enough to properly preload and maintain the preload on an AC bearing.
I noted that
3) Given that the dust seal washers between the crank arm or spider and the bearing is elastomeric, it will be hard to put enough preload on the thing.
But one respondent noted that
4) He thought that the hollowtech crank COULD supply sufficient preload.
I called Wheels Manufacturing, which offers both, at the same price (12/bearing). Javier stated that people buy both, and that both can work. The AC bearings require a bit more graunch on the preload, but (as the balls are more densely packed) you have more bearings supporting the crank in actual use. Javier runs ACs in his bike. Apparently, the dust seals are not a biggie (though if I ran the world, the dust seals would have a metal spacer ring on the ID for preload stiffness) in terms of squeezing out and losing AC preload.
I'm just so conditioned to like AC bearings (goes make to my Nuovo Record days, and my enthusiasm for precision machine tools, all of which pretty much use AC bearings in their spindles). I think I'm going to try them. I'll report back.
1) Use what came with the bike
2) The Hollowtech crank and the little "torque thumbscrew" aren't rigid enough to properly preload and maintain the preload on an AC bearing.
I noted that
3) Given that the dust seal washers between the crank arm or spider and the bearing is elastomeric, it will be hard to put enough preload on the thing.
But one respondent noted that
4) He thought that the hollowtech crank COULD supply sufficient preload.
I called Wheels Manufacturing, which offers both, at the same price (12/bearing). Javier stated that people buy both, and that both can work. The AC bearings require a bit more graunch on the preload, but (as the balls are more densely packed) you have more bearings supporting the crank in actual use. Javier runs ACs in his bike. Apparently, the dust seals are not a biggie (though if I ran the world, the dust seals would have a metal spacer ring on the ID for preload stiffness) in terms of squeezing out and losing AC preload.
I'm just so conditioned to like AC bearings (goes make to my Nuovo Record days, and my enthusiasm for precision machine tools, all of which pretty much use AC bearings in their spindles). I think I'm going to try them. I'll report back.
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WizardOfBoz
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03-11-17 10:23 AM
