One more SRAM question...thanks for the answers on the shifter question! But I have a long cage X9 9 speed derailleur and after a while the chain grinds away the inner cage right next to the upper pulley then the chain drops in there and off the pulley. The inner cage gets so spread out that it hits the spokes. I've replaced the inner cage twice now. Is there an adjustment I am missing that is causing this? Has anyone else seen this?