---Lightweight aluminum frame tubes are designed much more conservatively with respect to the ratio of diameter to wall thickness. The result is a frame that's
significantly lighter than its steel counterpart and yet is more durable. Yes, I
said it: more durable. The supposed frailty of aluminum bike frames is an Web
. Every torture test yet devised to gauge the longevity of production
bicycle frames has shown that even the highest-quality steel frames failed long
before aluminum and carbon frames.