Originally Posted by
Schwinnsta
If you want the same flex with Ti, the tube has to have a slightly larger diameter (thou it can be thinner). It is not a problem with clearances and standards. Aluminum has a even lower Modulus of elasticity and there seems to be no problem there. Aluminum would be the material of choice but for it not having a known fatigue limit. Because of that, manufactures have to use larger tubes than they would otherwise.
Well, I have been mistaken before.
I seem to remember a Ti mountain bike thread & chainstay/tire/crankarm clearance being an issue. The solution was some rework with thick, & tall rectangular tubes being used in that area, for a few inches of the chainstay, near the bottom bracket. The elasticity of Ti in thin gages of strength equivalent to some other materials made it such that things hit & rubbed in practice.
By extension, I can see other issues in frame design as well regarding harmonic oscillation (speed wobble,) & uninspiring cornering ability being concerns if
only necessary strength to do the job were the only consideration to frame design.
Nowadays with 1.5 inch tapered headtubes, thru axles & the occassional 83mm bottom bracket, I have no doubt designs able to take advantage of Ti's unique properties may be ripe for a renaissance.