Report "I have td one derailleurs front and back on my son's bike. The front derailleur cage drags on the big chainwheel teeth (the small bar that connects the sides of the cage is what is dragging). Should I adjust the height of the derailleur? I also cannot get his rear derailleur to index reliably. I have the high and low stops set right and I can index reliably from 5 down to 1 but not from 1 up to five. Any suggestions?"