Brake Wear issue?
 

I am talking to a friend of a friend about his brake wear on his Sti. He does track days and daily drives it. He's finding that his inside front pads are wearing at almost a 2 to 1 rate as the outside front pads? What would cause this? Old Fluid? Deeper problem? or is this normal? I've never noticed wear differences like that.

Any input would be great.

When I replaced my fronts, both the inside and outside pads had about equal wear.

Sounds like someone is bleeding his brakes improperly maybe? Air bubbles on one side prevent each side from getting the same force from the pedal?

I'd def say that he's not getting proper pressure on both sides of the caliper. Possibly some restriction, or *maybe* air in the brakes, but I'd be apt to think that would decrease pressure in the WHOLE system, and not just one side of each front pad... I dunno, maybe it could. How the f*ck do you get air stuck in just ONE side of a two sided caliper tho?

Sticky/stuck/wedged/frozen piston (Not likely if same both sides)

Damaged/clogged crossover tube. (Not likely if same both sides)

Contamination of the outer pads. (grease or other CF lowering / pad damaging compound. Could include "tire dressing" or "wheel cleaner") (Likely if same both sides)

Bad fluid or air in the caliper would affect the whole channel, not just one side of one caliper. How is rear wear?

Same on both fronts? If LI+LO = RI+RO or close to it then the system is probably OK. I'd focus on the pistons/pads on the side with the least wear and the crossover tube since lower wear is on the outside. One of those is likely where the issue is.

How's this guy's wheel bearings? Excessive play could mean more drag on one half of the caliper thus wearing the pads unevenly. Does he have excessive pad knock-back on track?