After a week in Les Arcs (and 2 pairs of pads later!), I was inspecting the rotors and found some odd wear patters. They are Formula 180mm rotors (front and rear) with Formula THE One brakes, and Superstar red kevlar pads.

If you cross sectioned the braking surface of the rotor, you’d see it as being flat (where there are no vent holes), then a dip inwards (on both sides) where the first row of vent holes are drilled, then flat, then a dip again where the second row of holes are, and finally flat again.

This is same on both sides of the braking surfaces and front and rear. The pads also have the ‘wobble’ line to match the rotors!

Never seen this before. The brake surfaces on the rotors were flat before the trip and new pads were fitted (twice!) during the week, and bedded-in properly.

Rotors wear out, less material = more wear, I suspect once it’s started it’ll only get worse as the worn bits tend to be rougher, meaning they end up doing the bulk of the work and wearing more.

There’s usualy a minimum thickness stamped on the rotor or written in the manual, get the micrometer out and measure them.

Have you used the Kevlar pads before?

It could be that they’re softer so compressing into the holes as the disc rotates and removing more material on the way back out again as they’re deeper into the hole.

I’ve had this with various brakes over the years. I think it’s abrasive mud/grit getting picked up in the holes in the rotor, then getting caught in the pad material and scraped across the rotor surface. Tears the pad to pieces too. Usually worst when its wet.

Superstar kevlar pads are utter crap purely because they wear the rotors much more than normal organic or sintered pads.

I’ve been using SS kevlars since they came out- they don’t wear discs faster than any other pad I’ve used, or if they do, it’s an inconsequential amount. I’ve used this exact combo for some time and never had any probs.

The Formula rotors that are made all of holes can wear unevenly just as you describe, I’ve seen it with a couple of sets- does still take a while though. Mine have had a lot of use and are still fine, the most worn out set I’ve seen had only ever been used with OEM pads.

How long do you expect a disc to last?

IMO..this happens to most rotors that have holes in them. Be it, car,bike, mtb whatever. If you want to cure it, then buy solid discs…although as with car discs, you’ll still get slightly uneven wear across the surface.

It should make the slightest difference to the rotors anyway, just the bedding in of new pads may take slightly longer.

There was a big thread on here about it approx 12months ago regarding their fitness for purpose (i tried to find it just but couldn’t). The newer style Formula rotors do seem to wear unevenly, as said above probably a result of the lack of material between the closely spaced holes.

When i bought mine direct from Formula i made sure i asked for the older style rotors.

TBH I’m a wee bit unimpressed that Formula spec these as standard with The Ones now… They’re good rotors, light and reasonably long lived, but they’re still a weightweenie choice sacrificing lifespan for lightness.

IIRC there are degrees of hardness for heat treated stainless steel, as used in brake rotors.
It was previosuly suggested that Superstar rotors were quite hard, so wore less and gripped less. Formula on the other hand are softer (relatively speaking) so wear more and grip better.
I can recall the thread where someone posted up an excessively worn Formula rotor looking similar to what you’ve just described.

Burchy1 – Member

There was a big thread on here about it approx 12months ago regarding their fitness for purpose (i tried to find it just but couldn’t). The newer style Formula rotors do seem to wear unevenly, as said above probably a result of the lack of material between the closely spaced holes.

When i bought mine direct from Formula i made sure i asked for the older style rotors.

Weird that- I tried looking for it as well, seems to have vanished!

Form previous threads: like this?

on this thread: http://singletrackworld.com/forum/topic/why-have-my-disc-pads-worn-like-this

Or this?

on this thread:
http://singletrackworld.com/forum/topic/pad-wear-vs-rotor-thickness-wear

Thanks for the replies. That first photo is EXACTLY the same wear pattern as both my rotors have!

So, looks like it’s just a ‘formula thing’ and it’s a case of either live with it or buy different rotors.

Do they still make them like this?

Had it happen to loads of them, they still work fine though, I just keep an eye on them.

Yes, this is still the current design.

That’s a bit rubbish then, they’ve been making that design about three years now.