I seem to be having a problem changing the cable for the rear der. on my XO twister. The new cable will not feed very far in to the grip, it only goes in until it feels like it's bottoming without following the curve. The cable is a QBP teflon coated one but I think it may be too thick, the one I took out wasn't the original cable and I do remember having some difficulty with it too, does SRAM use an extra thin cable?