Variable disk wear?

I’ve just measured the thickness of my disks (using proper disk callipers) to see if they’re at the minimum (24.9mm min, 26mm new).

I was surprised to find they are all slightly different. The front passenger side (RHD) was the lowest at 24.95mm, then driver side (25.1mm), the rears were 25.7mm passenger side and 25.3mm for the driver. So no real pattern and percentage wise quite a difference, given it’s only over a 1mm of wear. I did wonder if the braking system worked diagonally but the manual shows it all coming off the master cylinder.

There’s about 7mm left on the RS14s pads all round (2.5mm min).

Any thoughts?

Also, what are people’s thoughts on swapping the front and rear disks to even out the wear?


Hi Ian,

I wouldn’t worry about that.
In fact, the min disk thickness is only important in the front.
I have skimmed all the disks and they were then slightly below the min.
That wasn’t good for the front, as they warped immediately, but worked ok at the back, because they perform much less work.
Feel free to swap them around as there could be so many reasons why they wear like that that I bet you, if you buy another set of disks thinking that the wear pattern is going to repeat, they won’t (unless you have a problem with certain caliper pistons). I would put the thinner disks in tha back.

Regarding the pads, 7mm is plenty, enough for a track day ( ), but I would suggest buying another set and keeping it for the time when you really need to change them (like I did at Donington).
And don’t worry about the 2.5mm min, just avoid getting to the metal, otherwise you score the disks.


Cheers Uldis. The car currently pulls straight even under heavy braking so it’s not a problem.

I’ll swap the disks about.

Right, time for a posting on the correct place for stands…



If you take the rear disks and put them on the front dont you have to skim them first due to the smaller swept area of the rear pad and thus different wear “groove”

Also as a matter of ( possible little ) interest I have temperature tell tales on my front calipers and the front left shows 120 degree and the right one has yet to get to 100 … go figure that

Well yes, I didn’t mention about grooves, but the swept areas are different, so if you’re changing them back to front, they have to be pretty grooveless, otherwise, skim.

On the temp stickers, put several (3 of them) on each disk, that way you can average them (you know, sticker manufacturing discrepancies). If you still have the same you might have a problem with a caliper.

As a side note, I am probably one of the few guys that changes pads more often. So a tip here:
whenever you take off pads and want to reuse them, make them flat again by taking off the shiny part against a flat sandpaper (laid for example against a thick glass, or a very flat table).
That way you ensure two things, that you ready them to bed to the surface again, and that it’s flat, so whatever groove or wear pattern you had is not going to continue, but evened out.