FAQ: Brake Rotors and Pads

does not appear to be wearing any more than the HPS pads.


Rotor have 15k total miles on them btw.

Found some random brake pad info while researching pad taper. Most of it seems to substantiate our previous findings:

"Brake Pad Terms" from Afco Racing:

COEFFICIENT OF FRICTION
The scientific definition for coefficient of friction is the ratio of force required to move or stop one surface, with a given perpendicular force applied to it, as it drags across another surface. The layman can think of coefficient as the slippage of the pad as it clamps down on the rotor. The coefficient measurement ranges from zero to infinity, but most racing pad's range from .15 to .65. The mathematical formula for coefficient of friction is:

Mue = F/W

Where:
Mue = coefficient of friction
F = force required to move one surface over the other
W = perpendicular force

TRANSFER LAYER
This is what determines the stability and effectiveness of the pad's coefficient of friction. It is the simultaneous transfer of pad material between the rotor and the pad. Pad material is constantly moving between these two surfaces during brake engagement. Every pad leaves a transfer layer. This is one reason why a new pad will not work optimally against a rotor that had previously run a different type of pad.

TEMPERATURE CONTINUUM
This is a brake pads' comfort zone and signifies the range in which the pads are more effective. Some pads are designed to perform optimally at cooler temperatures while others do not start performing well until they are hot. The expanse of the temperature continuum is dependent upon the materials (powder, fibers, and resins) used to manufacture the pads. The thermal stability of these materials determines their combined effectiveness. Different materials have different properties at different temperatures. Very few brake pads are designed to retain performance while transitioning along the temperature continuum. The key to a great brake pad is to have one material transition in while another material is fading away; all without the driver feeling any difference in the brake pedal.

THERMAL STRESS / SHOCK
This happens when the rotor is heated up and cools down rapidly causing an uneven heat distribution throughout the rotor. The result is the expansion of the rotor material in one area, while not expanding in another area. Heat checks in the rotor are a symptom of thermal stress. Be careful not to confuse small cracks in the transfer layer laid on the rotor by the pads as thermal shock. Bedding of a new rotor will help reduce the possibility of thermal stress/shock.

RESINS
Resins are organic materials used to bind and reinforce the different components of a brake pad. The resins act like a thermoset plastic, which holds the components together like glue. This glue forms the matrix of the brake pad. When heated, resins tend to shrink and crack, and at very high temperatures they may turn to carbon. Carbonized resins cause weakening of the matrix and accelerated pad wear.

BRAKE FADE
There are three types of brake fade. The first is the conventional burning off of resins as the pads are being broken (bedded) in. This is known as green fade and occurs when gases from burnt resins are trapped between the pads and rotors. When this happens the pedal feels firm but the car will not stop. The second type of fade is when the pads are forced to work outside their temperature continuum. This is the point at which the resins burn off rapidly, and the pad has accelerated wear. The third type of fade is glazing. This is when the resins, which soften during active braking, then cool and solidify on the face of the pads. This glazed surface is hard and slick, and will not give the same coefficient of friction as an unglazed or new pad.

PAD TAPER
This is a rather disputed point among drivers, mechanics and manufactures of calipers and brake pads. The following are a few theories as to why pads taper.
One type of pad taper is leading edge to trailing edge taper. One theory as to why this occurs is that the leading edge (front of pad) is hotter than the trailing edge (rear of pad) and thus the front part will wear faster. Another theory for leading to trailing edge taper is as the pad material smears against the rotor it flows from the front to the rear of the pad and accumulates there, giving the pad a tapered face. A third theory is that pads themselves are not made to the proper density, and thus have uneven wear.
The second type of pad taper occurs in the form of top to bottom taper. In this case the top radius of the pad wears at a faster rate than the bottom radius of the pad. The caliper flexing under hard braking conditions may cause this. This problem is very common in racing where original equipment calipers are used. In many cases the original equipment calipers were not designed to withstand the high heat and high line pressure of a racing environment. Under these strenuous conditions the original equipment caliper bridge bends and flexes.

BEDDING YOUR ROTORS AND PADS
First, slowly build heat into the pads by making slow to medium speed stops. Then make a series of very hard high-speed stops. Some fade may be experienced when doing the high-speed stops. The brakes should not be dragged during this procedure. Let the brakes cool down for twenty minutes or more and they are then ready to race. Never use new pads to bed new rotors. It is best to bed new pads on old rotors that had run the same type of pads. It is best to bed new rotors with old pads that are the type that will be used in the race. A bedded rotor should have a uniform, polished appearance with no cracks or grooves.

Source: http://www.afcoracing.com/tech_pages/pad_term.shtml

AA wrote:

The second type of pad taper occurs in the form of top to bottom taper. In this case the top radius of the pad wears at a faster rate than the bottom radius of the pad. The caliper flexing under hard braking conditions may cause this. This problem is very common in racing where original equipment calipers are used. In many cases the original equipment calipers were not designed to withstand the high heat and high line pressure of a racing environment. Under these strenuous conditions the original equipment caliper bridge bends and flexes.

One thing i dont like about the f-body design is the bridge isnt strong enough. When bleeding the calipers i can visually watch it bend and distort when hard pressure is applied. If these were 4 pot calipers with some center bridge support i dont think we would have the same problem. guess nothing is perfect

Maybe so, but I haven't seen the kind of top-to-bottom taper they're describing as a result of the flex in the F-Body pads. Mine have worn amazingly even down to the last mm of compound. The rears (OEM) on the other hand showed significant tapering between the leading/trailing edges, as I posted here:

https://rivperformance.editboard.com/t2081p225-faq-brake-rotors-and-pads

My solution has been to rotate the pads every 15k miles or so keep the wear in check.

I think it's that time again to replace my front rotors.
I currently have EBC with about 35K miles on them and am getting a judder under light to moderate brake application that I cannot make go away by scrubbing the brakes anymore.
The scrubbing action has worked up until the past couple of months.
I do not get any judder when I do a very heavy brake application.
Have not had the opportunity to take things apart yet and do a visual as well as measuring the thickness of the rotors.
Have tried braking with just the E Brake to test and see if it was in the rear brakes, but they stop OK with no vibration.

Anyway, was wondering what product you guys are using lately. I've been away from the board and have not kept up with the latest and greatest evaluations of Rotors. Have done a search and a bunch of reading but can't find what I'm looking for, so I thought I'd just ask.
What manufacturer do you recommend.?
Where to buy from.?
How much are they selling for now adays. (Approx)

I remember sometime back AA mentioning he got some rotors with a lifetime warranty but can't find the info on that. Wondering how those worked out.
Also, I do have the F-Body calipers.

Thanks for any input you may have to offer.

Rick

I have had great results with powerslot rotors.
i think there is a link a few pages back for a better deal than zzp was selling them for.

Welcome back btw.

Matthew

Mr.Riviera wrote:

I have had great results with powerslot rotors.
i think there is a link a few pages back for a better deal than zzp was selling them for.

Welcome back btw.

Matthew

Thanks for the info.
I decided to read this whole thread to get back up to speed about what others are using and from what vendors your getting them from.
There is one mentioned by AA from a while back; Brakeperformance.com that has a set of fronts, slotted only, for $122.75 / pair with free shipping and free pads, which I won't be using. Can offer them up on here for the cost of shipping to someone.
Seems like a decent deal and a quality rotor. Won't know about the quality until I try them.
If, I try those. I'm still doing vendor research and have found some EBC's for reasonable money. Could always just continue with those.
It seems others are only getting around 35K miles while using an aggressive pad. I can't remember what color EBC pads I have in there now.
So I don't think the life I got out of my existing EBC rotors is unrealistic.?

Did I read on here somewhere that the F-Body Rotor is the same as the stock Riviera rotor (98).??????
If so I can order the rotors for an F-Body and get the free pads that will fit the F-Body calipers.???????

Yes, the F-Body rotors are the same as '98-99 Rivieras. EBC is a good rotor, but they don't provide lifetime warranty against cracking and warping. You also pay a little more for them, especially slotted and drilled varieties. Two brands that I've used recently and really like are Brake Performance and Royalty Rotors. The Royalty rotors were great. Got a decent life out of them, and never cracked or warped as promised. Only thing I didn't like was they come only in plain or drilled & slotted. I wanted slots only, so went with Brake Performance. Very similar in quality and performance.

I just reordered a new set of Brake Performance slotted rotors last week. They arrived yesterday, so will be putting them on the fronts soon. I like slotted only, as they contain a bit more material and should wear longer than drilled & slotted. Also, the zinc coating on the Brake Performance rotors seemed to prevent rusting longer than others I've tried.

If you order from Brake Performance, you only get the free pads if you go with their slotted & dimpled option. Slotted & drilled, drilled, slotted, and plain rotors do not include the pads. I once used EBC slotted and dimpled 'sport' rotors. They were all right, but made a very loud whining sound when brakes were applied hard. It's pretty cool, but maybe not for everyone. Best of luck in choosing a new set.

Oh... speaking of getting 35k out of rotors with an aggressive pad, wait till you see the rotors I'm about to take off the car right now. They are by far the most worn I've ever seen - not the rotors fault, the pads are just way too abrasive to be practical for daily use.

Cool

New Brake Performance rotors installed today. I will need new pads soon as well. It turns out that while providing the most amazing levels of friction I could imagine, the Hawk DTC-30 track pads will eat a pair of rotors in a very short time. If I hadn't noticed the wear soon enough, they would have broken through the to cooling vanes. That is no exaggeration.

I installed the first pair of Brake Performance slotted rotors May 28th of last year, with my HP Plus pads from previous install. It was a great combo. Here is a picture from July 5th with 2500 miles:



In early January of this year, the HP+ pads were getting thin and in need of replacement. Here's a shot of the rotors from 3 months ago:



They showed some wear, but nothing too alarming. I knew the HP+ would wear the rotors a little over time. I replaced the pads with DTC-30s and bedded them in. For a couple months everything seemed peachy. Then I noticed a couple weeks ago the slots were gone!

Here are the same rotors I took off the car today. It's difficult to see how much they've been turned down, but I'd estimate .060-.080" per side. Notice the notches around the edge - that's where the slots used to meet the edge.





It should be noted that these rotors are still very smooth, very even, very capable of stopping the car. All 4 surfaces of both front rotors looked identical, the wear was very consistent. No vibration or problems, either. I'm just afraid the condition will get to the point where it exposes the internal cooling vanes, and that would be very, very bad. Look closely - it looks like there's a pattern starting to show already.

Furthermore, the DTC-30 pads have already worn a liberal amount in just 3 months, and will need replacing soon. Note: these track pads are for the track. Those (no one here) who claimed they are streetable must be driving much lighter cars, and/or not doing a lot of daily driving. As much as I enjoyed the ridiculous bite these pads have, I won't be running them again. HP+ are en route until I can find a better option for replacement.

What many fail to understand after buying high perf. rotors,is the iron content of the H.P rotors. while Iron is a very stable alloy,it is finicky in its need to be constantly scrubbed. An iron rotor needs to be frequently resurfaced,meaning the rotors have to be broken in as if new.I am not a metallurgist by far,but I do know that Iron develops tiny surface protrusions that need to be scrubbed away.A pre "ceramic rotor" equipped race car left over night in a humid local,will need to be "re-broken" in the following day,before a race, after being left in the garage overnight . Prazzi,Brembo,to name a couple,have very high iron content.The higher the iron content,the greater the "pad -rotor" interaction will be. cheap rotors have low iron content,the main reason OEM.specifies "alloy" rotors for their production models.Ask any High performance Porsche owner,pre 1990,if their car exhibits strange shuddering on start up.......

Not sure exactly what you're saying robo, but to my knowledge, the OEM rotors are cast of grey iron, just like all high performance rotors. Grey iron by definition is a type of 'iron alloy' used for its desirable heat conducting properties.

There's no question these rotors were adequately scrubbed. They were scrubbed very hard every day!

A race team,will "break in" a iron rotor" every day" of the event. As far as I can deduce,you are not running A race ,daily.

That may be true, but it's the pad compound that caused this wear, not the rotor's composition. I noticed the same rotors showed less wear when used with a set of lower friction pads.

AA wrote:

That may be true, but it's the pad compound that caused this wear, not the rotor's composition. I noticed the same rotors showed less wear when used with a set of lower friction pads.

well,thats the whole question isnt it?! race teams "mate" rotors to pads. a small thing the manufactures of H.P. rotors wont tell you.

"Mating" is an interesting theory. I have another idea: race teams get brake systems replaced a lot more frequently than daily driven street cars.

Remember the pads & rotors I'm using on the Riviera have tens of thousands of miles on them. I got almost 40k out of the HP+ pads, and they worked great up till the day I changed them. A race car's brakes get replaced a lot sooner than that.

I installed a set of rotors and pads on our race team's track car, an Acura Integra, in 2009. We used the same rotors and pad combo I had on the Riviera. So far we've completed 4 races over the past 2 years, and the pads and rotors so far have held up very well. Each of our endurance races are 14 to 25 hours non-stop at 60-80 mph average lap speed. That's between 700-1400 miles per race. Many, many hard braking events, a few from 100+ mph. We never broke in our pads/rotors, we never mated them - just rolled the car off the trailer and raced. We didn't even properly bed the pads before the first race.

At first it would seem our race car's brake set up is more durable than the Riviera's, but remember it's the same set up on both cars - only difference is: the Riv is heavier and driven every day, at reasonable speeds with fewer braking events; the Integra is lighter, driven at higher speeds with much harder braking, but only about 3 days per year.

There's no way we'll get as many miles out of our Integra's pads & rotors as I have on the Riviera. At the current rate, we estimate the pads will be good to 6-7k miles, and the rotors, maybe 15k miles. That's a pretty long life for track car brakes. But when you look at the numbers, it turns out the Riviera gets much longer life from the same equipment.

If you want to know how race teams do it, read up at Zeckhausen Racing or StopTech's white pages. Racing is brutal on pads, rotors and calipers, and many teams will change the fluid and rebuild the calipers before every race or two. Rotors are considered a wear item, which is why they use replaceable rings on hats. Even the hats get replaced after a few races. Pads are replaced every few events, sometimes every race depending on the car, the pads, and the driver. In almost every case, brake parts will last longer on a street driven car vs. a high-speed racer, imo.

AA, I'm curious how many miles you wound up getting out of your DTC 30 pads?

I just finished a set on my 99 GP GTP with fbody brakes, and I was surprised that they lasted only a little over 2 months, couldn't have been more than 3000 miles tops (forgot to write down mileage ). Granted, those miles were pretty spirited. Having that level of braking power changed the way I drove and braked to a degree, and those miles / my commute had quite a number of stops from 70-80mph to zero for red lights. To put it in perspective, I ran HP+ pads before these, and they lasted a little over 2 years and ~22k miles. The DTC 30s also tore the hell out of my brand new rotors, leaving quite a ramp/lip in the outer edge. They also dusted incredibly bad, and for me, squealed about as bad as the HP+ (pretty bad). They did have amazing stopping power,though. This car is my DD, so it's not practical to keep running these pads, but it was fun while it lasted. Now I'm trying to figure out what I'll do next. Probably more HP+ pads as I thought that was a reasonable tradeoff. I'd like to do DS2500s (if they make that size yet for fbody), as I've really liked them on my cobra, but I haven't driven that car enough to know how long they will last. If they only last as long as the DTC 30s, I can't consider them.

I got almost 5k miles out of the DTC-30s, which included some long distance trips. They are worn down to almost nothing. Basically I had near exactly the same experience you had. I also had the HP+ previously, and they lasted a long, long time (outlasted the rotors), and so that's what I've switched back to. HP+ does pretty much everything I want for braking hard on the street, and they're not really that noisy on my car for some reason - I think it has to do with the way I use the pedal. I've "learned" to drive quietly with HP+.

For the track, I'd go back to DTC-30 compound, but I agree with you - they are near impossible for practical street use.

Good to hear that you had roughly the same experience as me (well, bad for us I guess, just happy that it wasn't just me). Honestly, I was a little shocked that they wore out as quickly as they did. The place I bought them from recommended them to me, based on how much I liked the DS2500s, as sort of an alternative to the HP+ that had better braking power, less noise, etc. Said they would be fine on the street, and made it sound like they were sort of a lateral move from the HP+ pads, only they had better specs. I wasn't made aware of the drastic tradeoff in pad/rotor life, though I didn't think to ask.

Live and learn I guess.

Hopefully people will read this when they are searching in the future, wondering if they are "streetable". IMO, yes, very much streetable in terms of "do they work well on the street." Very much not streetable if you're talking about using them exclusively on the street. Unless you don't drive the car much or have a budget of almost $100/month for brakes and rotors. Of course, if you also track the car, that's a whole different story.

BTW, our mods are very much similar

I said it earlier in the thread but ill say it again. Anyone looking for a set of pads with race level stopping, low noise and long life try the EBC blue stuff pads.

I have had them on my car for 6 months and 6k mile. they have a lot of life left, dont seem to be eating away my slotted rotors and still stop as well as day 1. I also constantly push them and cant get them fadded (120-0 or 2 stops from 80 with no problem)
Is there a negative to them? Yes. They have more dust than any pad i have seen and they do not work as well cold as the Hawks i had previously.
I keep meaning to pull the pads and check the wear + remeasure them but i just havent had the time. I can see through the wheels they look to be about 20% used and i hope that trend continues.

Good to know. I'm going to stay with the HP+ for now, mainly because I like how they work in really cold weather. I might decide to go with the EBC blue for track pads, and possibly a summer pad for next year. I really like hearing how they aren't eating your rotors up. The DTC-30s were ridiculous in that regard!

Just ordered HP+ replacements today.

I'll keep the blue stuff in mind for next time, but for now, I just wanted to get something tried and true.

On a side note, though, is it possible for a pad to dust like no other, but also have longevity? Kind of seems counter-intuitive. I know the DTC 30s made the dusting of the HP+ look like nothing, and the HP+ dust pretty bad themselves. I had been thinking that all that dust should have been an indicator of quick wear, but if the blue stuff pads can dust that bad and last? It just seems like all that dust is pad (and/or rotor) material that is coming from a limited supply, more dust = more wear, I would have thought.

i agree that more dust = less life from either pad or rotor.

however my rims show dust more than most due to the lip design and the chrome coating.
the hawk HPS pads i had on before dust a lot IMO

If you think the HPS pads dust a lot, the HP+ pads would redefine dust for you, and the DTC 30 would just blow you away. Imagine how much dust 2 entire pads and 0.100" of each side of a 12" rotor contains, and then imagine dumping it all out over 3k-5k miles, and you'll have an idea

Matt's right, it's either the pad or the rotor that's making that dust, and I've found it's mostly from the pads when it's heavy and black, or caked on, or a combination of both in extreme cases.

I've used the HPS, HP+, and DTC. I considered the HPS to be almost dust free, and the HP+ made a bit more. On a scale of 1-10, I'd rank them like this:

OEM: 1
HPS: 3
HP+: 5
DTC-30: 9 (saving 10 for a dirtier pad I've never encountered, but I can't imagine it)

I really don't think it gets much worse than the DTC, although I've heard Hawk Blue pads are very dusty, and they will corrode your wheels when it gets wet.

Based on the information in this thread, I feel the EBC Blue might be comparible to the HP+ in dusting, or slightly more (maybe a 6), but I think the source of their dust is different: the EBC is mostly pad dust, while the HP+ is almost all rotor dust (iron powder). I'm basing this on Matt's comment about the EBC blue pads wearing 20% in 6k miles, and my experience of the HP+ slowly wearing down rotors with almost no wear to the pads over 25k+ miles.

Of course, how you drive the car, and the car itself, makes all the difference. On our track Honda, HP+ don't wear the rotors much at all, as the pads are only used at high temps, so it's all pad wear in that case. I think these wear traits hold true with most all pads, being dependent on temperature range and driving style/application.