Originally Posted by
McBTC
Aluminum is lighter and hit it big in the burgeoning market for sprung MTB frames in the 80s. It's not the go-to material for custom frame building but apparently, once the investment is made in hydroforming technology, production-made aluminum frames are comparatively cheap given the fact aluminum is >4 times more costly than steel.
Aluminum is lighter but also weaker. High end steel is probably lighter for most frames.
Aluminum's primary advantage is probably that it does not rust.
Other materials are superior in every way.