Brake vibration due to pad deposits *with pictures*

Kin Mak · 3rd May 2007, 21:17

So a brief on the setup. Front Stoptech BBK with Axxis Ultimates and stock rear brakes with OEM pads(I am going to change them

).

Just did a trackday and this was the last on the rear rotors and pads. They are soon to be replaced by E46 M3 rear drilled rotors and Axxis Ultimates. Front brake pads are going to be replaced by either BHP XPS or Hawk HT-10 for track use, I will keep the ultimates for road use I suppose.

As you can see there is loads of pad deposit from the last trackday which is causing pretty bad vibration, worse as you put more pressure on the brakes. The back rotors are going to be changed so I don't really care about those

What is the best way of getting all that deposit off? Will rebedding the rotors get rid of it? Will me using the more abrasive HT-10 when I swap over get rid of them? Here are a few pictures... scarry looking I know. I wonder if you can just scrub the rotors clean...

supratony · 3rd May 2007, 21:54

Dave Zeckhausen has a pretty good article about this:
http://www.zeckhausen.com/avoiding_brake_judder.htm

rdm190 · 3rd May 2007, 22:11

Ditch the drilled rotors...

Kin Mak · 3rd May 2007, 22:15

Quote:

Originally Posted by rdm190

Ditch the drilled rotors...

Why would you say that? Do you think I should get slotted? I will but I ain't made of money so the drilled will have to do for the moment.

rdm190 · 3rd May 2007, 22:18

I would not throw them away, but next time do blanks or sloted.

Drilled rotors have proven to give no added benifit and IMHO they cause inconsistant pad wear and are more prone to cracking.

Kin Mak · 3rd May 2007, 22:20

Quote:

Originally Posted by rdm190

I would not throw them away, but next time do blanks or sloted.

Drilled rotors have proven to give no added benifit and IMHO they cause inconsistant pad wear and are more prone to cracking.

That is what I intend to do next. I got the brakes at a great price so I will bare with the drilled till I need to change em.

DZeckhausen · 4th May 2007, 00:02

Quote:

Originally Posted by rdm190

Drilled rotors have proven to give no added benifit and IMHO they cause inconsistant pad wear and are more prone to cracking.

Drilled rotors save about 1/4 pound of weight per rotor and they offer slightly better bite than slotted. However, under racing conditions, they do tend to crack sooner than plain or slotted rotors. This is a trade-off most racers are unwilling to make. For this reason, I agree with your conclusion that the next set should be slotted.

I do know a pro race driver who, while running in a very competitive series and laden with lots of "reward weight" as his penalty for winning lots of races, would use drilled rotors for his qualifying laps, then switch to slotted rotors for the actual race. The weight savings was enough to make a difference on the starting grid, but he was unwilling to risk using drilled during the race, lest they fail. I know another team in the same race series who were out of the points and, in desperation, ran drilled for the last couple of races in hopes of getting an edge. They got lucky and had no rotor failures. No points either, though. Oh well.

mottati · 4th May 2007, 00:07

the ht10s will clean off the deposits if you drive around with them on the street for a couple of days. When cold they work in "abrasive mode" when hot they work in "adhesive mode" so at street temps they'll clean the rotors. Ultimates are definately not track pads, as you see!
Mike