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      10-20-2019, 11:40 AM   #1
bentom2
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DSC off = Faster Rear Pad Wear?

Iíve finally gotten to know the M2 well enough to start running DSC Off at the last few track events. It was transformative as far as m experience with this car on track, so I intend to keep doing so on familiar tracks when itís dry.

One thing Iíve noticed though, is I went from using up front pads slightly faster than rears, to front pads lasting the 10 or so days Iím used to, but rear pads are only good for 5-6 days.

Has anyone else experienced this? Iím wondering whether this is coincidental and my rear calipers need some attention, or if the rear brakes are still assisting in controlling wheel spin, and without DSC managing throttle, the rear brakes are just working harder.

Iím running square 265/35/18 RS4s, Pagid RS29s, and SRF in an LCI with stock calipers and rotors. Different tire (Bridgestone S007) before I started running DSC off, but otherwise same setup all year.

Related question; whatís everyone elseís front vs rear pad life? Even? Fronts go first? Rears?
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      10-20-2019, 01:53 PM   #2
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I assume you're using the same pad compound front to rear? If I have a good theory why you see higher rear wear.

I think this has most to do with the square setup you’re running. All cars are designed with a brake force distribution which forces fronts to lock up before the rears. But in your case you’ve increased front grip, while keeping rear at factory level. That means that front locking pressure has increased from say 100bar to more like 110 or 115 bar.

So you’re reaching higher Master Cylinder locking pressures because the front can now lock at higher BAR of pressure.

So the front can take more decel, without locking, but the rear is still subject to higher pressures because brake system pressure is driven by the max overall pressure. So if you reach too much pressure in the rear, ABS or EBD will take care of it, but the pressure from the master cylinder is still higher than it would be in factory staggered configuration. So the rears can’t support more, but are still exposed to higher brake system pressure leading to more heat. I bet the rears are getting hotter than fronts leading to quicker pad consumption.

It should be more or less even front to rear.

Last edited by 5.M0NSTER; 10-20-2019 at 02:01 PM..
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      10-20-2019, 02:51 PM   #3
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I run a square setup and always all electronics off. Running PFC08s all around, I get about 12 days on my fronts and double the amount of days on my rears, or about 24 days.

Something else seems to be off with your pad wear experience.
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      10-20-2019, 04:21 PM   #4
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This is interesting!

I run PFC 08 all around on factory 245/265 setup. After 3 days on some pretty long circuits (Spa, Nordschleife) I have very even wear front to back.

Now I really wonder why we all have such different experiences.
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      10-20-2019, 04:39 PM   #5
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Quote:
Originally Posted by 5.M0NSTER View Post
I assume you're using the same pad compound front to rear? If I have a good theory why you see higher rear wear.

I think this has most to do with the square setup youíre running. All cars are designed with a brake force distribution which forces fronts to lock up before the rears. But in your case youíve increased front grip, while keeping rear at factory level. That means that front locking pressure has increased from say 100bar to more like 110 or 115 bar.

So youíre reaching higher Master Cylinder locking pressures because the front can now lock at higher BAR of pressure.

So the front can take more decel, without locking, but the rear is still subject to higher pressures because brake system pressure is driven by the max overall pressure. So if you reach too much pressure in the rear, ABS or EBD will take care of it, but the pressure from the master cylinder is still higher than it would be in factory staggered configuration. So the rears canít support more, but are still exposed to higher brake system pressure leading to more heat. I bet the rears are getting hotter than fronts leading to quicker pad consumption.

It should be more or less even front to rear.
Same compound front and rear. Interesting theory. FWIW, the rear calipers are still blue, unlike the fronts, but OTOH, the dust seals have started melting recently. They were fine when I put the last set of pads in (pre-transition to DSC off). Fronts were cooked by midsummer (see below).

Quote:
Originally Posted by dvas View Post
I run a square setup and always all electronics off. Running PFC08s all around, I get about 12 days on my fronts and double the amount of days on my rears, or about 24 days.

Something else seems to be off with your pad wear experience.
Great data point. If a few others chime in with a similar experience, I may need to do some investigating.

I plan to rebuild front and rear calipers and replace all rotors over the winter in preparation for next season though, so if it is a caliper issue, perhaps Iíll address it with this refresh. I already rebuilt the front calipers over the summer when I noticed some uneven pad wear and a little bit of pad drag on one while driving.

Could be the rears are just ready for attention as well. Maybe theyíre dragging now and Iím just not hearing the signs of it. With all the extra stuff going on in the rear, between the drivetrain and parking brake, itís harder to tell with a wheel off.

Curious to hear from some others though.
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      10-20-2019, 09:52 PM   #6
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Quote:
Originally Posted by bentom2 View Post
Iíve finally gotten to know the M2 well enough to start running DSC Off at the last few track events. It was transformative as far as m experience with this car on track, so I intend to keep doing so on familiar tracks when itís dry.

One thing Iíve noticed though, is I went from using up front pads slightly faster than rears, to front pads lasting the 10 or so days Iím used to, but rear pads are only good for 5-6 days.

Has anyone else experienced this? Iím wondering whether this is coincidental and my rear calipers need some attention, or if the rear brakes are still assisting in controlling wheel spin, and without DSC managing throttle, the rear brakes are just working harder.

Iím running square 265/35/18 RS4s, Pagid RS29s, and SRF in an LCI with stock calipers and rotors. Different tire (Bridgestone S007) before I started running DSC off, but otherwise same setup all year.

Related question; whatís everyone elseís front vs rear pad life? Even? Fronts go first? Rears?
I'm in the same league as you. Just started nannies off, but do not find any difference with wear between font and rear. BTW what a difference!
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      10-21-2019, 05:27 AM   #7
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Nannies fully off or MDM? Im still on MDM and love it, car is so playful

My wear seems even front to rear on 255/275 18s with Endless ME20 in the front and ME22 in the rear.
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      10-21-2019, 08:32 AM   #8
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Your rears are going to wear a lot more in MdM mode. Judging from your comment, you are driving in both mdm and dsc off. Once in you are strictly in dsc off, you'll see an increased rear pad longetivity.
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      10-21-2019, 10:25 AM   #9
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Quote:
Originally Posted by Megator View Post
Nannies fully off or MDM? Im still on MDM and love it, car is so playful

My wear seems even front to rear on 255/275 18s with Endless ME20 in the front and ME22 in the rear.
Quote:
Originally Posted by landapanda View Post
Your rears are going to wear a lot more in MdM mode. Judging from your comment, you are driving in both mdm and dsc off. Once in you are strictly in dsc off, you'll see an increased rear pad longetivity.
I was running MDM/traction for the last year prior to switching.

In the LCI, Megator, MDM/traction is just subtly more tolerant of slip angles than sport and not at all fun to drive in. A friend that I track with has an M2C, and weíve discussed the difference. Pad wear, as I said, was almost even, with fronts wearing slightly faster than rear when I was running in MDM.

The move I mentioned in the OP was from MDM/traction mode (short button press) to OFF (long button press). Iím very familiar with the characteristics of MDM/traction mode, so Iím confident Iíve successfully held a button down for 5 or so seconds until the warning message pops up in the instrument cluster display.

landapanda - my assumption was that Iíd see longer rear pad life as well with the move to OFF (long button press), but that hasnít been my experience so far. Iíve seen your track lap time and other track oriented posts. Are you typically running DSC off? If so, whatís your front vs rear pad life?
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      10-21-2019, 11:19 AM   #10
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Quote:
Originally Posted by bentom2 View Post
I was running MDM/traction for the last year prior to switching.

In the LCI, Megator, MDM/traction is just subtly more tolerant of slip angles than sport and not at all fun to drive in. A friend that I track with has an M2C, and weíve discussed the difference. Pad wear, as I said, was almost even, with fronts wearing slightly faster than rear when I was running in MDM.
I only have exp. with the Euro MDM (im in the EU) and it allows a lot of slip before it kicks in so was just wondering

I agree that typically rear brakes will take the brunt of ESP interventions so your case is a bit odd!
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      10-21-2019, 12:12 PM   #11
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bentom2 - do you feel like you are getting good braking performance? Any reason to think could be an issue with the car - maybe have it checked out? Something funky sounds like it is going on - burning through rears almost twice as fast as fronts definitely doesn't sound right. How does the car feel under heavy braking in MDM vs DSC off? And now that you are running stickier tires has the braking performance increased?
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      10-21-2019, 12:59 PM   #12
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I thought of so thing else. Simple explanation this time. Is is possible the rear pads are actually a different compound? If you had street compound on the back and race compound on the front the rears would disappear in no time.

Iíve gotten the right part number box, with wrong part numbers inside. Also got right pad shape with wrong compound before as well.

Maybe not, but sometimes the simplest explanation is right.

Pads disappear quick when they operate over their heat rating. So either your rotors are getting too hot or the pads canít take it.

Last edited by 5.M0NSTER; 10-21-2019 at 01:22 PM..
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      10-21-2019, 09:25 PM   #13
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Quote:
Originally Posted by bentom2 View Post
Quote:
Originally Posted by Megator View Post
Nannies fully off or MDM? Im still on MDM and love it, car is so playful

My wear seems even front to rear on 255/275 18s with Endless ME20 in the front and ME22 in the rear.
Quote:
Originally Posted by landapanda View Post
Your rears are going to wear a lot more in MdM mode. Judging from your comment, you are driving in both mdm and dsc off. Once in you are strictly in dsc off, you'll see an increased rear pad longetivity.
I was running MDM/traction for the last year prior to switching.

In the LCI, Megator, MDM/traction is just subtly more tolerant of slip angles than sport and not at all fun to drive in. A friend that I track with has an M2C, and we’ve discussed the difference. Pad wear, as I said, was almost even, with fronts wearing slightly faster than rear when I was running in MDM.

The move I mentioned in the OP was from MDM/traction mode (short button press) to OFF (long button press). I’m very familiar with the characteristics of MDM/traction mode, so I’m confident I’ve successfully held a button down for 5 or so seconds until the warning message pops up in the instrument cluster display.

landapanda - my assumption was that I’d see longer rear pad life as well with the move to OFF (long button press), but that hasn’t been my experience so far. I’ve seen your track lap time and other track oriented posts. Are you typically running DSC off? If so, what’s your front vs rear pad life?
I have had best results with pfc08s. I can usually get at least 8-10 days on the fronts and 10-12 days on the rears w dsc off. In mdm mode, the rears wear out faster than the fronts (after about 6-8 days).
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      10-21-2019, 11:57 PM   #14
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Quote:
Originally Posted by OG Shark View Post
bentom2 - do you feel like you are getting good braking performance? Any reason to think could be an issue with the car - maybe have it checked out? Something funky sounds like it is going on - burning through rears almost twice as fast as fronts definitely doesn't sound right. How does the car feel under heavy braking in MDM vs DSC off? And now that you are running stickier tires has the braking performance increased?
No braking issues. I even set some personal best lap times. I drive a fairly long ways from home to the various local tracks, so Iím leaning toward pad wear from slight caliper drag. This would also explain the dust seals suddenly showing signs of heat damage that wasnít present prior. Maybe just enough drag to generate some heat/wear, but not enough to cook the pads or cause fade on track.

Quote:
Originally Posted by 5.M0NSTER View Post
I thought of so thing else. Simple explanation this time. Is is possible the rear pads are actually a different compound? If you had street compound on the back and race compound on the front the rears would disappear in no time.

Iíve gotten the right part number box, with wrong part numbers inside. Also got right pad shape with wrong compound before as well.

Maybe not, but sometimes the simplest explanation is right.

Pads disappear quick when they operate over their heat rating. So either your rotors are getting too hot or the pads canít take it.
I probably would never know. Other than wear, everything felt 100%

Thanks everyone for the responses. Iíve seen enough to confirm this isnít normal, so time to do some work. Iíll rebuild the calipers in a few weeks and see what happens at my next track event in November and/or the drive to/from. The season is winding down here, so itíll be a few months before I can get enough time int to confirm whether that fixes things. Would love to see the rear pads start lasting longer than the fronts like the rest of you.

Thanks again.
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      10-23-2019, 02:56 PM   #15
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Fronts wear much faster than rears.
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      10-23-2019, 05:40 PM   #16
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I run in intermediate groups with DSC off, pfc08s. My fronts are wearing faster than my rears. My front calipers are discolored and my rears look new still
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      10-23-2019, 09:40 PM   #17
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Nannies off, square, stickers. Fronts wear faster than rears. Front calipers are brown/black but rears are blue.
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      10-23-2019, 11:03 PM   #18
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Thanks for the latest responses. A rare case of everyone on the internet agreeing on something.
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      10-24-2019, 03:20 PM   #19
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My data for you:

Same square setup but on RE71s. PFC08 in front, Hawk HPS 5.0 in rear (I run the rear pads for both street and track to save the extra pad swapping).

In 7 one-day events this season I've been really impressed with the wear rate of both sets of pads. The PFC08 are a remarkable step up in performance from the stock pads!

Front calipers are British racing green , rears are still blue. Car feels great under braking (tho I'd love some stoptechs one day). I agree with others on here that it doesn't seem right your rears are wearing so quick.

As for the change to DSC Off, wow, what a brilliant change to actually learn and develop slip angle in this car. You simply can't achieve it in the DSC modes, or trailbrake properly - for US LCI at least. Now I'm finally dancing with the car and it's a great feeling to work up to the traction limits and try to keep it right there.

Good luck with your brake thing!
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