Rear brake pads wear out faster then front?

[integrals]

Realistically I've probably gone through 7 sets of fronts and 4 sets of rears in the last 5 years of TT racing and 30,000 miles of street driving.
But thats also doing 8 sessions a race weekend, 12+ times a year and I do change them out between 2 and 4mm depending on what track is coming up.
So actually Ken's numbers are pretty right on.
I used to run the Carbotech XP-10's in front and XP8's in the rear.
Recently stepped up to the XP-12 front and XP-10 rears.
They actually seem to be wearing better, time will tell.



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The last 3 times you were out in TT in your NSX was at FB West, you ran 1:09 and I ran 1:05, FB Main before that you ran 1:10 and I ran 1:06, then on FB East, you ran 1:08 and I ran 1:03.
Going faster usually results in better times and more brake pad usage depending when and how hard you brake, as you well know

The last 3 times i've been out in TT, I was also on street tires Some comparables (on NT01) are 1:03 at East (couldn't find date, but will never forget the ONE time I beat phil lol), 1:07 at west (8/25/2012), and the 1:07 at main (10/28/2012). My point was that two different cars that run similar times can have completely different brake wear patterns! Thats it buddy All of the more 'recent' TT scores for me were on NT05 and Azenis. 2013 was a relax year as will 2014.

I also suspected we had simlar type brake compounds which would also suggest that you SHOULD wear more than me given the similar weight / higher entry speeds. Mind you I haven't replaced my brake pads or tires since 2012 at this point. At the track I was LOL'ing about how my current set of tires are from 2011!

 

[SlipAngle79]

To clarify, are you running the HP+ on rear AND the front? or a more aggressive pad up front? Obvious question but seems odd that the rears would burn so quickly.....are they older than the fronts or changed at the same time? If a caliper was sticking you would feel it immediately, but, some times the rods on the outer edges of the caliper (guide pins?) can over heat after the dust boots crack and allow enough dirt in there, deforming the rod and causing it to expand in the cylinder - thus slowing down the caliper piston movement and perhaps causing the pad to stick just a LITTLE bit on the rotor.....might be a longshot but that scenario has happened to me on both my S2000 and another car I had, a Vigor, both times on the little rear calipers. It erased the rear pads on both cars without any dramaticly noticeable handling effects, in fact, I happened to be looking those cars over and noticed the rear pads where almost down to the backing plates....changed rear pads, and while changing them, noticed that one of the two guide pins was stuck. Have a look and let us know.

 

[jwmelvin]

I was running HP+ both ends. Installed new sets simultaneously. Have never felt anything odd about braking with the pedal. The handbrake seemed tight, and would require only a couple clicks usually. That loosened up over time, which was the time during the initial set of HP+. So I suspect that could be a factor.

But after a winter with HPS, another set of HP+ went on with new rotors for a couple more track weekends and seemed to have the same issue. The third weekend on the second set, the rear pads were down to less than 5mm and I got substantial/serious fade by the end of a 30 minute session. The fronts were getting worn but were not nearly as close as the rear.

Unrelatedly, at the same event, I totaled the car (no injury). I'm still working through the issue with my insurance company so will report later. It has been emotionally difficult, to say the least.

Edit: the guide pins holding the calipers to the brackets seemed to move freely as far as I can remember. But that is not the freshest memory.

 

[SlipAngle79]

Unrelatedly, at the same event, I totaled the car (no injury). I'm still working through the issue with my insurance company so will report later. It has been emotionally difficult, to say the least..

That sucks! I assume you are pretty sure it was not a rear brake-related issue? Obviously a loss of braking force at either end of the car is going to greatly diminish total stopping power right when you don't want it. Anyway, good luck, and I hope you get another one!

 

[nsx-sf]

Hate to take the thread on a slightly different tangent, but being as my question is HP+ and uneven wear related, it seemed better than creating a new one.

I've got the more normal pad wear pattern, in that the fronts are down to less than 20% and the rears are still a bit over 50%. These are currently stock pads front and rear.

However, I'm thinking of putting the Hawk HP+ on the front and leaving my stock rear pads on until they wear down sufficiently, then going HP+ all round. My car is bone stock, and I'd describe my track driving as safe, smooth but relatively slow.

Is this mix up wise in a track driving scenario, or should I go HP+ front and rear at the same time? I'm also a bit curious about whether the HP+ noise and dusting is really as bad as everyone says?

 

[Rope]

Dust is bad, noise is none on my car.

 

[docjohn]

Hate to take the thread on a slightly different tangent, but being as my question is HP+ and uneven wear related, it seemed better than creating a new one.

I've got the more normal pad wear pattern, in that the fronts are down to less than 20% and the rears are still a bit over 50%. These are currently stock pads front and rear.

However, I'm thinking of putting the Hawk HP+ on the front and leaving my stock rear pads on until they wear down sufficiently, then going HP+ all round. My car is bone stock, and I'd describe my track driving as safe, smooth but relatively slow.

Is this mix up wise in a track driving scenario, or should I go HP+ front and rear at the same time? I'm also a bit curious about whether the HP+ noise and dusting is really as bad as everyone says?

judging by your description of your track pace I would say you will be fine trying the hp/oem combo.

 

[jwmelvin]

I'm sure it would work okay but the bite of the HP+ is way higher than OEM so your bias will be way forward. I would use the same pads front and back. This is not the reason for my preceding answer but I do have some new-in-box HP+ rears for sale.

 

[docjohn]

the initial "bite" of this combo will be fine, the rears may start to fade as his season progresses and more bias may shift to the front as you summarized but I still think he will be fine.....but I know how opportune that was for a quick fs segue ...

 

[jwmelvin]

Honestly that wasn't my purpose. Since, for a given amount of pedal pressure, rear braking will be much less, that will shift the bias. I feel like the pedal pressure for OEM vs HP+ is 2:1 or 3:1. OEM pads probably work just fine for initial track days but I don't see why you'd want to set up a car in a way that is going to throw the balance off.

 

[nsx-sf]

Seems like the sensible thing to do would be to replace all 4 at once - I actually already bought a set of front and rear, but thought I could save some $$$ (i.e. cheap out) by letting the stock rears wear down first. However, on reflection maybe brakes aren't the right place to be saving a few bucks on track days!

 

[docjohn]

the only really bad bias you can have in a car on track is rearward...we don't have that problem on the oem.In the end you must do whatever makes you happy and confident in your car on track whether it helps or not.

 

[nsxtasy]

Go for it! I've swapped and mixed the HP+ and NSX OEM pads on both tracked cars - the NSX as well as the ITR - with no ill effects whatsoever. And yes, I mean using the NSX OEM pads on the ITR front. (The NSX stock front pads are a different part number, and presumably composition, from the ITR stock front pads, although they are interchangeable.)

I think you would be fine with that setup (HP+ in front, OEM in back). They're actually quite similar in most respects. People like to diss the NSX stock pads just because they're stock, but they're actually quite good.

 

[jwmelvin]

One other thing to consider: I never had fading problems with HP+ pads until my rear pads were quite worn and I tried to get one more track day out of them. They started to fade badly by the end of each session. Apparently the heat transfer is much faster through a thin pad into the caliper. I had freshly bled Motul RB600 fluid. Maybe I already posted about this above but I think it beats repeating for those starting to track. Painful to pull off a half-worn pad but I have found it to be potentially important.

 

[nsxtasy]

I never had fading problems with HP+ pads until my rear pads were quite worn and I tried to get one more track day out of them. They started to fade badly by the end of each session.

More likely that it was your front pads fading, not your rears.

Like many street and street-track pads, the HP+ pads will experience "green pad syndrome", fading the first couple of sessions you use them on the track. Once they go through a couple of heat cycles like that, they shouldn't fade much if at all. It sounds like this is what happened with your front pads, and you may have incorrectly attributed that to the thinner rear pads. Just guessing, of course.

 

[jwmelvin]

Without a doubt, that is certainly possible. I suspected the tears because they were so thin. Maybe 2-3mm. The fronts were about half worn. I had driven the car as a two-driver vehicle for a weekend (first set of pads) and for another two weekends (second set of pads) without issue. Always the same setup. Then when using a set of pads for the third weekend I began to have fade. Whether front or rear I will never know. I figured if the fluid boiled anywhere then there would be a soft pedal. The only thing that changed was pad thickness and it was especially thin in the rear. But perhaps the half-thickness front was the problem.

 

[ac011]

I just replaced new brakes master cylinder, Motul fluid and HP+ rear pad. Both pads were installed at the same time and my front still have 40-50% left. I check the guide pins that holding the calipers and it looks at little dry. I lub them both to see if it will make a difference. Can you test the hand brakes by jack up the car and spinning the rear wheels?

Anyway, I will be in Laguna Seca next week to test out the wear.