mark kibort

great street pads are mintex racing pads. (still pretty soft compared to what we normally use) or their street pads, if you are not ever hitting the track. OR, pagid black street pads. you will not be disapointed.

mk

mark kibort

no, this is not the case at all. most of the bedding process is getting a good fit between the materials which are never perfect, even new.

I can clean off the rotors to have NO film on them and they work just perfect. (done this, and also changed a rotor, not a pad with no bedding needed) once the resins are baked out of the pad, the rest is mechanical , and that just gets better with time. sure , there is a little more going on with film of material that is probably transfered in the first couple of hard stops, but its no the majority of bedding process.
the brake pad guys seem to know less about the process than the race guys that use them from my experience. Just like talking to the tire guys about pressures. (unless you are a pro team sponsored by the tire manufacturer )

Tampa 928s

I am replacing the pads with a set acquired from Roger but have a question.
What is the best way to scuff up the rotors before I install the new pads.

blown 87

They make special tools for this, but the thing that gets as close to that as I have seem, is to mount the rotor and hit it with a die grinder WFO with a Roloc pad on it while spinning the rotor, you end up with a pretty good crosshatch pattern if the speeds are right.

Everything has to be clean, soap and water then use Wurth brake clean, wear latex gloves to keep the oils from your hands off of them.

Make sure the slide areas in the caliper are 100% clean and use something like Wurth CU1100 on the metal to metal contact points.

Tampa 928s

Replaced the pads with Rogers' BR Deluxe Advanced Ceramic Technology Pads.
Instructions stated go to 40 hard brake to 10 drive 1/4 mile repeat 9 times
All I can say is what a difference!

mark kibort

a nice cotton washcloth, and brake clean. the shop type papertowels work too.
the cross hatchng should be a part of the normal rotor surface after it was machined at the manufacturer. you start taking power tools to it, you will probably do more harm than good. IMO

mk

blown 87

He is using used rotors Mark.
It has a lip, that only comes from wear.

brianrheffron

This link gives a long explanation on why brakes need bedding in
and the way I read it is that especially for modern pads that work
in the higher temperature ranges it is not just a simple case
of getting a good fit between the disc and the pad.
The bedding in process transfers material from the pad to the disc.
http://www.stoptech.com/tech_info/wp_bedintheory.shtml

mark kibort

then I would see a machine shop and turn them, as I do with my collection of donated used GTS rotors 1mm above the minimums. or toss them!
anything else is a waste of time. the surface is uneven, grooved and a mess after they have been worn to give you a lip. just put on some pads, as we do throughout the racing life of a rotor, and there is NEVER any issues until I see some crackingin the rotor, where they will then be pitched. new pads on old rotors, needed to be bedded. once they are cooked, they are good to go. I can put a new rotor on used pads and they are good after one lap. any material transfer happends that quickly.

mk

mark kibort

yep, thats all true and correct. the part left out, is that the pad material transfer happens very quickly for most pads with steel rotors

mk

brianrheffron

On this topic I am only passing on what I have read and researched.
Mark on the other hand has experience by the barrow load.
Interesting that he finds that with old discs but new pads they are
good after one lap which probably means five or six hard applications.

mark kibort

You got it backwards. new rotors, old pads, take one lap to be good. new pads on new or old rotors take about 2 laps, a cool down lap and then they are good. I try to simulate this on the freeway, and its no comparison. after a half of a session on the track, I can get the pads to be white half way through their thickness. you are hard pressed to just get a 2mm white area by doing the same on the freeway. the main goal is to cook the resins out of the pad. (as well as a diposit of material on the rotor, and surface matching)

one lap is more like a hard application every turn, so usually its about 10 applications, depending on the track.

what do I know, I just do this about 3-4 times a year.

mk

blown 87

I know of no maker of rotors that recommends turning rotors and they have not in many years.
They do recommend what I say to do however.

I will bow out to your obviously greater knowledge than I have.

mark kibort

I dont know of any maker that advices trying to burnish or resurface, even clean up the surface using power tools either.

Those manufacturers have good reason to recomend just buying new ones and thats obvious. but, machining is machining. if you can turn a rotor to a smooth surface that is within the limits of the thickness, there is no reason you cant do it, but NO manufacturer will recomend it, though it is done all the time.

Since I have had absolutely NO issues with brakes, besides using stock rubber lines that have blown , I dont think I am guiding anyone down a dangerous or incorrect path. When there is no racing budget, I just turn rotors. when there is, I buy new ones. there is no difference in feel or stopping power, or even life expectancy. Actually, i think the used rotors last longer after turning them, because possibly the metal has stablized or changed over many years of street use and the sudden racing duty, is not "shock" to them. Thats a guess, but Ive got 5 race weekends on the used GTS, turned rotors and never got more than 3 without serous cracks with new ones ( but they did have some holes in them too. )

littleball_s4

Yep, no problems here with turned rotors either.

Mark, Obviously we kind of have different problems with brakes not properly beaded. In several categories I've been (open and closed wheelers, track and rally), if the break in period is really short, the rotor develops blue circular spots (5cm diameter) and the vibrations are unbearable. It happens to one team every other day with 20 cars in the track. You have to toss/turn the rotors after the session. If the break in period is short but close to optimal, the wear is not even, parts of the pads do not touch the disc and fade comes quicker. Also, cracks develop sooner. You usually change the rotors at the end of the day. If the break in period is ok, you can keep the rotors for as long as the thickness is ok (three or more weekends sometimes)

I understand when you do not properly run the brakes in, you get massive fade, and all you have to do is let them cool and start again?

So, obviously, as we talk about racing 928s, you are the wise man! But keep in mind that the things we say here may not be valid for other kind of cars.

Best regards!