I have only seen bikes with fork lowers made of aluminum but when I took mine off my bike they had a lot of rusty spots leading me to beleive they are steel. I disassebeld them today cleaned them up and painted them black and they looked great but when I went to put them back on the wheel, I tightened the locking bolt on the right side and the clamp snapped. I used a tiney socket wrench that had a 3in long handle and put very little force on it and it just snapped so now I need to weld it back on. Just wondering what material it actually is.