pedalpedalpedal

I understand that compared to steel, aluminum is more fragile. It snaps, not bends. But there are plenty of aluminum mountain bikes and trials bikes out there, and those disciplines can make a bike take a beating. Why is it different for BMX? BMX racing isn't exactly a walk in the park either.

Greyryder

For BMX racing, it is the same. The majority of BMX race bikes are made from aluminum, these days. We've had AL race frames since at least the early 80s, but it didn't really catch on until the mid 90s. Racers tend to love the stuff, since they can get a stiffer frame, and lose a few ounces in the process.

The "steel is real" contingent is still very strong in racing, though. Too many headtubes have been seen snapping off on the track. Makes a few people nervous about aluminum. And, some people just want a frameset that they can beat on for years.

It's freestyle where aluminum frames have never caught on. Freestyle can stress frames in ways most other forms of cycling never will. There's also a lot of abrasion damage, do to grinding tricks, that would quickly eat through an alloy frame.