For those of you still riding Shimano 10-speed XTR or Saint rear derailluers, don't despair. Shimano still offers the essential wear item, the XTR RD-M980 Derailleur Pulley Set. It takes quite a bit of riding and some muddy, grimy conditions to wear these composite pulleys down. It is actually amazing how well these lightweight (20g) pulleys wear and tolerate constant use while pedaling, with very low friction. Most riders and mechanics will see visual wear first in the lower Guide pulley, and when that wear is clear, potentially affecting chain performance, it is best to replace both pulleys. Even if you can't see the obvious wear on the upper pulley, it will be be found in wear on the shoulders of the teeth, not in the teeth themselves.

This replacement set includes the two pulley wheels: Guide and Tension. Both have excellent mud clearing properties, feature 11 teeth, and precision sealed bearing assemblies, but are not interchangeable. The Guide pulley (upper) features cut-outs and has sharper looking teeth that offer excellent chain wrap and guidance that are essential as you shift up and down the cassette. The directional Tension pulley (lower) has shorter, thicker teeth that are designed for long wear and efficiency under the heavy spring tension delivered by your M980 or M820 series rear derailleur, especially if the clutch is engaged. Keep your premium drivetrain running properly at all times. This XTR RD-M9000 Derailleur Pulley Set is crucial to overall performance, so when you clean your drivetrain or inspect your bike, pay attention to the details.