marudy

Guys, I recently realized that for disc brakes the inner pads are the ones to go out faster. So I asked myself why don't we interchange them when they are at the half of their life?
But does it make sense? The disc has different wear from each side, wearing the pads in different ways as well. What do you think?

Dietcoke

If your pads are wearing unevenly, you probably have an issue in your sliders.

Icedawg

On my Spec Miata, and previously on my Spec RX7, I always flip the pads inside to outside part way through their life cycle.
As they get thinner, they wear unevenly, and swapping them helps reduce that and extend overall life.

On a street car, I would swap them more often, say after every 25 % wear, since on a race car the stresses will more quickly re-bed them to the surfaces on opposite sides, even with a fairly large difference.

There could be a problem with your sliders, but there is a fundamental problem with the uneven torque the single piston, floating caliper design that Mazda uses on both of thee cars, which gives uneven wear. The problem is worse on a track car than a street car, so if your car is not tracked, the sliders may well be the issue.

marudy

I haven't taken them down to see what is happening yet and id they are uneven by much.

My realization is towards the fact that pads do tend to wear uneven and indeed it's more visible when they get thinner indeed. Usually when pads are done, one side has a bit more material while the other one is done. I plan to do some cleaning and lubrication maintenance on my disc brakes this or next week so my question was more in regards to if it makes sense to swap them like we do for tyres etc in order to extend their life overall.

Thanks for the sliders tip though!

sixshooter

iTrader: (12)

Icedawg,
Uneven torque? How many pounds of difference do you expect to see from one side to another when you are able to easily slide them by hand?

A more reasonable explanation will be worn pins, flexing pins, worn bores in the casting that pins slide into (which typically don't get sleeved in a rebuild/reman), flexing calipers, or some of each. I've seen excessive pin to bore clearance on freshly reman calipers. The main culprit was the bore.

Schroedinger

I've had the inside pads wear out sooner (actually much sooner) in two different Miatae with stock/original calipers now. I agree that the problem is worse on the track. I don't understand the technical reasons why, but I would propose that the outer pad probably gets more fresh air on a stock Miata and stays cooler, slowing the wear. I do switch inner and outer pads halfway through their life. They bed in to the rotor profile pretty quickly; if you have deep grooves in the rotors, it's probably time to replace those too.