JRitt@essex

Hi,
Yes, it's absolutely fine to 'tune' your handling using different compounds at either end of the car. I've seen Subaru STI guys do the opposite...run a higher mu in the back to get the rear to rotate. Just keep in mind however, that if you you run DS3.12 and DS1.11 front, you are shifting a slight amount of brake torque to the end of the car with the higher mu. In other words, you are putting more work on that end of the car. In the case of running DS3.12 Front / DS1.11 rear, you're shifting a bit more work/heat load onto the front brakes. That's fine as long as your front brake can handle that additional heat. Good question.

JRitt@essex

You guys may want to check your alignment...rear toe and/or camber. We've had many, many occasions on which we've had clients ask us about rear brake bias issues, and 98% of the time it turns out being a suspension issue, not a brake issue. For example, the customer installs one of our brake kits alongside a set of coilovers. They go out to the track and the rear is dancing around. Their initial gut reaction is to call us and say, "Your brakes shifted too much bias to the rear." Since our brake systems very closely match OEM brake torque output at both ends of the car, we know that isn't the case. Once they do some deeper digging and work on getting their suspension setup properly, their brake bias issues disappear and all is well. That may not be the case with you gents, but I wanted to put it out there. Suspension is always my first suggested avenue to investigate if a car is wanting to swap ends, particularly if the car has stock brakes or a properly designed aftermarket brake kit.

JRitt@essex

Short answer:
If the pads are just scorched and not mechanically run on a disc, then yes, you should do a traditional bedding procedure.

Long answer:
Scorching vs. burnishing/bedding
Many pads you see sold today are called pre-bedded, but they are actually scorched. What that actually means in almost all cases is that the pads have been scorched in an oven as the final step in their production process. The pads are placed on a conveyor belt and sent through what you and I think of as the broiler in your kitchen oven (using flame or infrared heat). Sometimes pressure is also applied to the pads during that process, but not all the time (because that process is more complicated and expensive than simply heating them). The scorching process bakes out some of the binding resins from the top layer of the pads that will make contact with your discs. That top layer becomes a little softer, more porous, and easier to conform to the face of your brake discs (when you bed them in on the discs). Ferodo Racing brake pads are scorched in this manner under both heat and pressure.

However, what happens with many manufacturer or sellers, is that they advertise their pads as being pre-bedded, when in fact they are simply scorched. We consider the bedding/burnishing process to be when the pads are mechanically pressed against an actual brake disc. We have two burnishing machines that we designed, built, and patented. We are able to run pads on the discs and lay down an actual pad transfer layer. That is essentially the same thing that one would attempt to accomplish on a racetrack or deserted road. With the machine however, the process is computer controlled and ultimately repeatable. We offer this as a service to our AP Racing brake kit customers. In that case, they pads and discs are truly 'ready-to-go out of the box.'

Below are a couple related videos.

ShahulX

i just drove home 40 minutes on cold (its cold outside 35 degrees F) Ferodo DS3.12.. Castrol SRF fluid, otherwise a stock 13 991.1 4S... they really dont bite well (much at all) when cold... lol, just an FYI

ShahulX

the DS 3.12 is very close to a race only pad. They claim as such. The downsides apparently are:

- could wear out rotors much more quickly on the street
- cold brakes don't stop

I found the latter out immediately - first few times driving on the street I had to warm them up by repeated braking just to be able to brake at all on the street. Since my car is mostly used to drive to/from the track and of course on the track (or carving twisties) I felt that this is a reasonable compromise. Since I don't do stop-n-go driving or commute in this car, the 3.12 is an ok compromise for the street to be able to drive to the track.

Scott[/QUOTE]

Yea, should have read this lol.. hopefully they are great on track.. if I do some daily driving should I do the Ferodo 1.11? or just warm up the 3.12 if more concerned about track fade?

donR

I've been using DS 3.12 with my 982 Cayman for the last year on Trofeo R tires. No issues on the street but I drive accordingly and I agree they need a bit of warm up. I think I have had occassional issues with the ABS on the track and strange pedal feel but probably due to my braking technique as I'm fairly new to track driving. Otherwise they seem to have been good, a lot better than the OEM pads. I am thinking to try DS 1.11 next for comparison and to see if it suits my braking ability a little better and my street/track tires.

My question is how low can you let the DS 3.12 pads wear to before needing replacement or how many more half track days do you think I will get? I think they are at around 5mm mark. Fronts look to be a little lower:

brewerbry

Pads in top pic are toast! They are very thin and will transmit a ton of heat into the fluid and start to fade soon. Bottom pic is getting close but you might have another couple of track days in them...

srwhitman

You can't eyeball, you have to measure. 5mm - in my opinion, that is fine for 1 track day at least - probably 2. That was exactly my situation 1.5 weeks ago when I took my car to the track. Yes, its true, the closer you get, the more they heat up (and the issue isn't so much fade as these things last but that the closer they get to minimal pad depth, the faster they wear). I have observed this but I've talked to a number of experts about it too as I thought it was non-linear toward the end and its definitely true.

Now after my 2 track days (6 sessions one day, 5 the next) I drove home 200+ miles. Obviously all highway so not a lot of braking. I parked the car in the garage, then next day took it out to get it washed and I did hear a bit of squeaking which worried me that I went down to the rotors. I have new pads but I need to change my tires too and I somehow lost my brake pad measurement tool. Hard to say what they are down to now - definitely need replacement but I don't know if my discs are toast as well. They were getting worn (girodisc) but I sincerely hope I didn't overdo it.

I will report back.

Meantime, I think it very much depends on the track, your ability, how hard or how much you brake so there is no one right answer. I have a Lotus that uses Gloc pads and they start off at only 6mm so 5mm is an eternity there but that car weighs only 2000 lbs so its comparing apples to tomatoes (both are red fruit but....).

PTSFX

Quick update after my day with the 3.12 in front and 11.1 in rear. Car was much more stable under braking. Only issue is the pad wear/crumbling that I commented on in the other thread: https://rennlist.com/forums/racing-a...-it-toast.html

JRitt@essex

In terms of wear and when to swap out the pads...We use a general rule of thumb that when the pad compound itself wears down to the same thickness as the backing plate, you need to seriously consider swapping them out. Obviously it depends on what you plan to do with them next. If you plan to run some light laps on a super easy braking track on street tires, that's a very different situation than running hard laps at Watkins Glen, Road America, or Sebring on racing slicks. In those cases you need to ensure you have plenty of pad left. Keep in mind that the thinner the pad becomes, the faster it will burn. That means if you got 100 laps out of the first half of the pads, you may only get 70 laps out of the second half of the pads (or less)! The inner and outer pads also tend to wear at different rates, so you need to be careful to examine the inner, not just the outer pads. Again, we cover these topics and many others in our article below. Please take a few minutes to read it, and it will save you a lot of questions and potential headaches. Thanks!

Essex track and racing pad owner's guide

KNSBrakes

Also be aware that just because you see some meat on the top of the pad doesn't meant the inner pad is the same. This is due to pad wear taper.

We have noticed brake pad taper in all Porsches driven hard on the track. Aggressive red group drivers pushing the limits we have seen 3mm of pad taper or more.

The rule of thumb we use is to replace if the pad material is thinner than the backplate, or if you are going to run them that thin then check the inside pad for taper.

--Aaron

srwhitman

I took my front pads off and while I've seen taper as such on my Lotus (difference of perhaps 2mm), I didn't notice it in my GT3 (both sides were pretty thin though - about 2.5mm) but definitely agree, taper can occur and its really hard to see the inner unless take off the rim and by that point, well, not much more to just replace the pads. The problem is at the track if you don't have a way to replace and/or didn't bring replacement pads. Then you have to also bed them in too so I think best to do ahead of time.

I have been running Ferodo DS3.12 for the last year on the fronts - still had some room left on the rears with Pagid Yellows but now I'm going DS3.12 all the way around. I realize that in effect did put more temp/wear on the fronts but they seemed to hold up ok. COTA is pretty bad on brakes - 3 very high speed braking (straight into a hairpin) events whereas other tracks I go to aren't as bad.

donR

Just as a follow up on my post above on the brakes in my 718 GTS. I took everyones advice and booked into my workshop ASAP. Unfortuantely the pads were worse that what could be seen from the outside with one rear down to the backing plate on one edge and one front almost down to the backing plate. There was also vertical and horizontal taper so the pads have also worn unevenly, in some places up to 2.5mm thicker along the bottom of the pad compared with the top. This has worn a groove along the innner circle of the rotor so I was advised to replace the rotors as well given the inner circle of the rotor is lower than the outher circle. I'll post some photos in a minute, where I think you can see the issue, including the uneven wear of the pads.

Being new to track driving this is a bit of a suprise to me but I've learnt about what people have said above, but also to check my pads more regularly, and that you really can't tell the condition from the front. My workshop suggested that I also rotate the pads due to the uneven wearing of the pads which should make the pads and rotors last a little longer. I was told that the DS3.12 pads were suited to the Girodisc so perhaps it is the level of track driving I am doing that is also wearing the pads and rotors prematurely. The events are time attack/supersprint so definitely hard on brakes, but I'd say these rotors have lasted less than one and a half pad sets, although that is probably 90%+ track driving.

I'm also thinking perhaps I should upgrade to AP racing brakes in the future and/or possibly the larger 991/992 6 piston brakes. Or maybe persevere with the current brakes and monitor more closely. Look forward to further suggestions.

donR

Here are the photos of what's happened so maybe others can also learn from my experience. You can really see how uneven the pads have worn.

These are the front DS3.12 pads:


And the rear DS3.12 pads:


This shows the horizontal taper:


And now the vertical taper where the pad is thicker at the bottom than the top, which is what's worn the inside circle of the rotors:



This photo shows the inner circle of the front rotor worn away:


This one is of the rear rotor wear:

PTSFX

Lesson learned - just be glad you caught it before your next event. Those pads were for sure needing to be replaced two track days ago and yes, that rotor is toast.

GiroDisc make great rotors based on my personal experience.