Inner and outer brake pad wear

[jarrett2016]

fellow owners-My 2005 cdi has 159000 miles on it. I've changed the pads once (front at 91,000, rear at 75,000) and have the orig rotors. I drive out west a lot from Florida and other highway driving. I just checked the fronts with the idea of doing a complete brake job (rotors, pads, fluid, wheel bearings) and noticed on the front, the inner pad on both sides is considerably more worn than the outer pads. Both have worn about the same, the inners are about 1/8 in and the outers maybe 1/4 in. The rotors are just within spec (25.4) so I will do rotors also. I will do the job in the next month or so but wonder why the inners wear so much more. Checking one set of the old pads that I had kept, the same situation. Everything works well, just curious. The replacement pads are MB from the dealer. steve

[Werkstattmeister]

Hey Steve,

In many applications, the inner surface of the brake rotor runs hotter than the outer surface due to decreased cooling airflow. Sometimes you will see ventilated rotors whose inner disk is thicker than the outer disc to provide additional thermal mass. The added mass allows the inner rotor to absorb the necessary thermal energy while starting out at a higher temperature, without exceeding the critical temperature for the materials. The higher temperatures cause the inner pad to wear faster.

You should consider using some aftermarket brake pads that produce less brake dust than the OEM pads. I have been very happy with the Akebono pads I put on my car.