Old 05-13-21, 09:42 AM
Generally bewildered
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Originally Posted by ClydeClydeson View Post
Bad idea. Ti is not as strong per cross sectional area as steel, so a part designed to be made from steel but then Ti is swapped in will result in a significantly weaker part. If you are a very lightweight person then it might be OK, but for the absolute minimal improvement it's not worth the trouble - any trouble.
Pure Ti and some of the less rigorously controlled (Tofu-grade) Ti stock from China are not as strong as steel. But some Ti alloys (Ti-6Al-4V - Grade 5, is at 1100 MPa, or 160,000 psi yield strength) are stronger than some steels (e.g. 4030 chrome-moly, 470 MPa or 68200 psi yield strength). In further support of ClydeClydeson's point, Ti is less stiff than steel. Which is why the Ti pedal axles you see are much thicker than steel axles. There's limited space inside the pedal (and you have to be able to slide the inboard bearing over the length of the spindle) and I think that this is why Ti spindles are more rare.

Getting a part made from a good quality alloy (and being certain that it's good stuff) will be expensive. The paperwork alone to certify that Ti stock is Ti-6Al-4V (Grade 5) would probably be a few hundred bucks. But it is machinable. From my viewpoint, not worth the effort. But if this sounds fun to you, don't let us naysayers get your down.

Last edited by WizardOfBoz; 05-14-21 at 08:03 AM.
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