Which is stronger, carbon or aluminum? We smash two rims on the floor to find out.
The first (the carbon rim) rim was ridden very heavily for a year by a pro downhiller. It was his rear wheel and was just starting to show cracks but was still true and round. The second rim (the aluminum alloy rim) was ridden for a couple months by a 120 lb lady. It was her rear wheel and she had put a big dent in it.
The carbon rim took a serious beating before new cracks started to show. And even after all we did to it, it was still true and round.
The aluminum alloy rim was clearly deformed after the first two hits and just kept getting worse until we were able to break it by hand!
Carbon vs Aluminum Mountain Bike Rim