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Yep, gotta be off with the fairies to imagine a 24mm ally BB is gonna fly. Pretty hair-raising thought, all those chumps riding around on a nasty con job...
Kimmo-
gotta be off with the fairies to imagine a 24mm ally BB is gonna fly
KCNC have been making ISIS (that's 22mm isn't it?) BBs with a "Scandium" (i.e. refined 7000 series aluminium alloy) spindle for many years now. Probably no more deadly than square taper (16-17mm) titanium 🙂
https://www.kcncstore.com/kcnc-scandium-race-lite-bottom-bracket-ita-70-isis-promotion/
gbj_tester
And also 30mm. What seems like a small difference becomes huge when the torsional stiffness is proportional to the 4th power of diameter. 30mm aluminium alloy axles are fine, 24mm ones are a terrible idea. For a given load, the stress is reduced by about 60% using the larger axle. In the relevant region of the curve for 7075T6, that can easily be two orders of magnitude greater fatigue life.