With Cobalt's recent company changes, I wound up having to look for a new pad (I had previously been using Cobalt Spec VRs, absolutely no complaints whatsoever, great pedal feel and modulation, no fade at all, plenty aggressive). After searching around and talking to some people, I settled on Carbotech's XP10 (and as a sidenote, HUGE for Carbotech's customer service guy, fantastic to deal with!). Bedded the pads as given in the little instruction sheet, took them out for my first two sessions on track this weekend and at first I was pretty damn disappointed. Pedal feel was crappy, even after extensive bleeding, and modulation was ok.

The third session out, I'm guessing maybe they bedded in more or something, because they really started grabbing then. Throughout the rest of the weekend, I had absolutely zero fade and great stopping ability. My one and only complaint was the pedal. I'm still trying to figure out what exactly was going on, but it felt as if my brakes had to be SERIOUSLY bled, though I had done that already. Sander was also just trying out the XP8s on his Integra and had a similar complaint.

The question, mostly for anyone who's driven on both types of pad (Spec VR and XP-x), is this: has anyone noticed a similar issue, or are both Sander and I having some other unrelated problem? I didn't have a chance to ask anyone else there, as I was running around the whole weekend.

 

did you also replace the rotors with the pads? If not that might of been the issue for the 1st few session. Pads will bed in much faster on new rotors.

(I have tried both spec VR and xp10's) they are both real nice pads with great stopping power, no fade, good modulation, it was just that the spec VR's lasted much longer on my car, so I run them instead.

FWIW, right now I'm trying the Hawk HT10's and I think they have just a wee little bit less stopping power than the VR's, no fade at all, good modulation, and seem to last longer than the VR's. I can't wait to try the new VR's out but who knows when that will be.

 

Yep, brand new rotors.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sscguy &raquo;</TD></TR><TR><TD CLASS="quote">...for anyone who's driven on both types of pad (Spec VR and XP-x), is this: has anyone noticed a similar issue, or are both Sander and I having some other unrelated problem?</TD></TR></TABLE>
I was also on XP 10 this weekend (Fri-Sat-Sun) after a long stint of only using Spec VR.

The Spec VR seemed to require less bedding attention, and had better cold bite, IMHSO.

Pedal feel for the XP 10 was a little weird, and they seemed to require more pedal pressure than the Spec VR did for the same haul down.

Once I got used to the pedal feel and need for a little more pressure, I felt the XP 10 were just fine performers and I would probably buy them again. I don't think they are <u>quite</u> up to Spec VR performance, and we all know that one of the biggest advantages of the Spec VR was that you really could use them for a couple of years without having to change them, and they were also very kind to the rotors.

However, I'd subjectively say that the XP 10 are a close second. There's also the huge advantage to the XP 10 that they are actually available!

I did not have a feeling that the brakes needed to be bled. Just a feeling that a little more pedal pressure was required than was required for the Spec VR.

Using new rotors this weekend, yes.

 

George, it looked like the XP 10's did there job with Corey passing every car in group 3, in some interesting spots also.

I think they did well considering your weight was in the car with him...

 

I am seriously going to kick your ***.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 577HondaPrelude &raquo;</TD></TR><TR><TD CLASS="quote">...Hawk HT10's and I think they have just a wee little bit less stopping power than the VR's, no fade at all, good modulation, and seem to last longer than the VR's.</TD></TR></TABLE>
If they do all that I might have to try some of those, too.

 

Sounds like the difference between a linear and progressive pad. Cobalts tend to be linear, Carbotechs historically tend to be progressive. At least, I think Matt mentioned something about this years back. Some people like one pedal feel more than the other, pick your poison.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WRXRacer111 &raquo;</TD></TR><TR><TD CLASS="quote">Sounds like the difference between a linear and progressive pad. Cobalts tend to be linear, Carbotechs historically tend to be progressive. At least, I think Matt mentioned something about this years back. Some people like one pedal feel more than the other, pick your poison. </TD></TR></TABLE>

I'd like to hear more about this comparison. And George, that's maybe a better way of explaining it, the more pedal pressure required. I never felt as if the brakes were letting go on me or anything, but the pedal did have to be depressed much further than normal, to the point that heel-toeing was becoming difficult.

 

If your pedal is soft, you didnt get them bedded in enough, or you glazed them....

 

Just ran XP12/10, after a stint of maybe 4 sets of Spec VR's?

Agree on the bedding-- I bedded mine on new rotors during a practice session. They took a bit to really get bedded, pretty much a full session at an easy pace. They were shuddering for a little while (which had me worried, I am short on spare brakes..) I probably should have done a few hotter laps then a few cool-down laps instead?

After that, they all looked a bit ugly, but they worked great. NO soft pedal issues, on a car hitting 145-153 indicated on the back straight of Mid-O, and occasionally getting deep in the braking zones. Motul RBF600 that hasn't been bled for a couple of weekends (no need?)

-Chris

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">or you glazed them.... </TD></TR></TABLE> I'll check that. I take it you haven't had any problems with them?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sscguy &raquo;</TD></TR><TR><TD CLASS="quote">Yep, brand new rotors.</TD></TR></TABLE>
takes a while to get a pad transfer layer.

ive been using carbotech brakes for a while, and one complaint Ive never had was pedal feel. The brakes come on RIGHT NOW when you even look at the pedal funny

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Cobalts tend to be linear, Carbotechs historically tend to be progressive. </TD></TR></TABLE>

Linear = progressive

All of our pads must be bedded on track. The 1st session on them is never a good indication of their performance.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MaddMatt &raquo;</TD></TR><TR><TD CLASS="quote">All of our pads must be bedded on track. The 1st session on them is never a good indication of their performance.</TD></TR></TABLE>

I think this is true for most brake pads. Brake pads often exhibit what is sometimes called "green pad syndrome", wherein they fade big-time the first (and sometimes second) session you get them fully heated up to track temperatures, then grip well for the remaining life of the pad.

 

If I'm reading this right, they ran all weekend on them and still have the same issue... I don't think its a bedding issue given that info...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MaddMatt &raquo;</TD></TR><TR><TD CLASS="quote">

Linear = progressive

</TD></TR></TABLE>

Matt, please explain, I'm confused.....

 

I think I asked the wrong question.

given a graph of torque on the Y-axis, and pedal/line pressure on the X-axis, if we say "linear" that would be it, a horizontal line at some . brake torque wouldn't increase as you increased pedal pressure.

so your math function would look something like Y=500 where 500 is a fixed torque value.

A progressive pad would have a curve that looks more like
Y=X. that is, a fixed input yields a fixed out put in a directly proportional relationship.
That makes sense.

I think what I should've said... is "do carbotech pads tend to ramp brake torque relative to line pressure" faster than other pads?
ie, maybe brake torque vs. line pressure more closely resembles a Y=X^2 curve compared to other pads which might have a Y=X curve?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">a horizontal line at some . brake torque wouldn't increase as you increased pedal pressure.
</TD></TR></TABLE>

I call that "fade" since increasing the pedal pressure no longer increases the torque generated. I can under no circumstance understand where a pad like that would ever be an asset to have.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">given a graph of torque on the Y-axis, and pedal/line pressure on the X-axis,</TD></TR></TABLE>

Imagine a line at a 45 degree angle on that graph. *That* is the definition of a progressive, linear brake pad. The 2 terms "linear" and "progressive" mean the same thing and are interchangeable.

The problem is, all friction material at some point go non-linear. Their curve may start linear, but go parabolic at some given pressure. That's when you have controllability issues. Slight changes in pedal pressure might generate large changes in torque and cause wheel lock-up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxtasy &raquo;</TD></TR><TR><TD CLASS="quote">
Brake pads often exhibit what is sometimes called "green pad syndrome"....</TD></TR></TABLE>
I've experienced that, in the old days, and the XP 10 don't do that. I never meant to to say that anything like that was going on.

They just require more bedding than the VR, and (IMHO) more pedal pressure.

Nothing at all like the green pad syndrome, which is dangerous.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mtm68 &raquo;</TD></TR><TR><TD CLASS="quote">If I'm reading this right, they ran all weekend on them and still have the same issue... I don't think its a bedding issue given that info...</TD></TR></TABLE>
It wasn't really an "issue" for me. It was just a "difference," that's all.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MaddMatt &raquo;</TD></TR><TR><TD CLASS="quote">All of our pads must be bedded on track. The 1st session on them is never a good indication of their performance.</TD></TR></TABLE>

MaddMatt: Perhaps I'm mistaken, but don't you have a note on the bedding instructions that if you let the pads sit for a full 24 hours the bedding will be even better? I run the XP-9s, and I bedded them in on an empty side (country type) road on Sunday morning following the instructions (several 60-30mph runs, then 60-0, etc), then I came home and parked the car. I did this a few days before the track day. Pads work great, pedal feel hasn't changed, but I only used the Cobalt spec B before in comparison.

I guess if your car is not street legal it won't help, or if you just put on the pads on track day it you don't have a choice. But I think bedding them very early in the morning and let them sit for 90 minutes or so will also help, as I did that on a track day before.

 

Verbatim from our bedding instructions:

"For bedding on street prior to use:

-Brake 4-6 times from 40-60 mph down to 30 mph with firm steady pedal pressure.

- Repeat these procedures by braking to a complete stop from 40-60 mph about 3-5 times.

- After these excecises the brakes should be very hot

- If need be, repeast these steps until you feel the brakes are hot, but NOT smoking.

- After you are satisfied the brakes are hot and bedded, allow the brakes to cool down completely by parking the car for 30 minutes.

For track use:

All cars, especially heavy cars (ie cars about 3000 lbs or greater) will require one "light" track session to get the brakes to near full racing temps followd by the recommended cool down, so as to develop maximum brake torque and to improve pad wear at race temperatures. Carbotech Performance Brakes recommends a 10-15 minute session of 6/10ths to 7/10ths braking effort followed by 1 hard lap, then followed by a 30 minute stationary cool down."

24 hour cool down doesn't hurt, but you really don't gain anything either.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by George Knighton &raquo;</TD></TR><TR><TD CLASS="quote">I am seriously going to kick your ***.</TD></TR></TABLE>

I thought threats of violence (serious or otherwise) were banned on this board?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MattP &raquo;</TD></TR><TR><TD CLASS="quote">

I thought threats of violence (serious or otherwise) were banned on this board?</TD></TR></TABLE>
I apologise for the perception of a threat, if you are not joking.

Smitdog and I have known each other for quite some time, and we have been driving together for quite some time.

Believe me, it was not a threat.

Rear brakes: This past weekend was the last time I am going to be able to use the Spec B that I have on the rear.

If I have XP 10 on the front, what should I have on the rear?

XP 8 ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by George Knighton &raquo;</TD></TR><TR><TD CLASS="quote">If I have XP 10 on the front, what should I have on the rear?

XP 8 ?</TD></TR></TABLE>

Yes. Just make sure you don't act like a moron and try to brake at the 100' mark after hitting 150mph on the straight at Summit.

Jason-
who says, "the white flag made me do it"