Fed up with breaking plastic SRAM derailleurs, I replaced the system with XTR. I gave my old stuff to a buddy including a broken 9.0SL which he figured he'd send to SRAM to see if they'd warrantee it. Hey, all they could do is say no. It was warranteed site unseen. They didn't want the broken one and sent him a new 9.0. But this one had an aluminum top knucle. Hmmmm. has SRAM finally figured out that plastic in some bike parts is prone to breaking easily???