Originally Posted by
Buglady
Aluminum frames do have a shorter lifespan than steel, just because of the different characteristics of the metal. Over time it does become more brittle. That's been an acceptable trade off for the stiffness and (relatively) light weight, as well as the ease of manufacturing and relatively lower cost.
I think the lifespan of an aluminium frame depends on the manufacturing process and quality control...I have an aluminum framed MTB with a rigid steel fork, it's 12 years old and has been ridden very hard, both off-road and on-road including tons of exposure to road salt during winter and the frame is still solid with no signs of failure.