Steel BB30 Fixed 55 x 20
03-02-11, 02:10 AM
#26
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Last I checked, the Modulus of elasticity for steel was higher than aluminum... and the shear modulus is much higher (~25 vs. ~75).
Sheldon Brown does a good job of explaining why aluminum tends to be lighter:
Anyway, I think the bike is sweet. Keep up the good work!
Sheldon Brown does a good job of explaining why aluminum tends to be lighter:
Steel vs Aluminum
The situation with aluminum is even more pronounced. The "identical" aluminum frame would be 1/3 as stiff as steel, roughly half as strong, and 1/3 the weight. Such a frame would be quite unsatisfactory. That's why aluminum frames generally have noticeably larger tubing diameters and thicker-walled tubing. This generally results with frames of quite adequate stiffness, still lighter than comparable steel ones.
The situation with aluminum is even more pronounced. The "identical" aluminum frame would be 1/3 as stiff as steel, roughly half as strong, and 1/3 the weight. Such a frame would be quite unsatisfactory. That's why aluminum frames generally have noticeably larger tubing diameters and thicker-walled tubing. This generally results with frames of quite adequate stiffness, still lighter than comparable steel ones.
03-02-11, 07:54 AM
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Thanks everyone. I'm as interested as all of you as to the reaction of the pros in Boulder. The banking at Boulder is some of the steepest in the world. I'm crossing my fingers that we're not going to have crank arm interference so the testing can move forward. It seems that the BB Shell is source for many questions. What isn't reflected in the photos is the massiveness of the Seat Tube and Down Tube. I would have not been able to braze the tubes to a traditional BB Shell. StayTuned!
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Track Cycling: Velodrome Racing and Training Area
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