Originally Posted by
Scooper
Everyone is entitled to his/her own opinions, but not his/her facts.
It is a fact that aluminum has no fatigue limit; it's not just my claim or my opinion. The lack of fatigue limit is a well documented physical property of the material. I made the point in my post that competent designers of aluminum bicycle frames consider this fact when designing frames.
No offense was intended.
I just wanted to point out that it is somewhat overstated.
In (theoretical) cases of very light loads, I don't think that the statement applies. Certainly if you bounced a helium atom against a piece of aluminum tubing (at low velocities), there would be no real limit to the number of stress cycles.
I also have to wonder whether a frame built of hefty, thick aluminum tubing would ever really fail when used by a light and gentle rider. The frame would probably last for centuries if not millennia -- almost certainly so if the rider were gentle enough with it.