EGbeater

iTrader: (35)

Awesome; thank you for your input Ferreira! Has anyone had experience with running Raybestos ST-43s in the front, and ST-41s in the rear? From what I've read, the Raybestos pads appear to last longer than PFC.

Another question: should I remove my front OEM rotor dust shields to increase the rotors' exposure to cooling air? Remember, in my case, I'm already using brake cooling ducts.

EVOBrakes

iTrader: (67)

A few thoughts on the heat.

Even if the pads are said to be good to 2000 degrees - the rest of your brakes are not. Ideally you'll be in the low 1000's or so for optimal performance. Past 1500ish everything starts to wear/fail so much more rapidly.

I am not so sure running less pad up front will decrease temp's/improve wear unless you brake less. From an energy standpoint that is the only way to put less load into the pads.

EVOBrakes

iTrader: (67)

If it's mostly a track car you can remove them.

But remember - they also shield tie rod ends etc from rotor heat so you have to wrap everything that becomes exposed.

EVOBrakes

iTrader: (67)

I don't see how you can brake hard for 3 track days and not wear pads.

I would fully expect set of front race pads to last about 2 weekends at most (roughly 2 track hours per day - 4-30 min session) - or less.

?

EVOBrakes

iTrader: (67)

Just another thought

I think the wear accelerates rapidly with temperature.

In other words - for the first 10-15 mins of the session the wear is low as heat builds.

Then the rotor/caliper/wheel/pads etc start to get soaked and temps continue up -

We know temps can exceed 1500 ish - perhaps the majority of wear occurs in those last few laps when the whole system is soaked and heat cannot be rejected?

EVOBrakes

iTrader: (67)

Rear race pads are available now

Smike

iTrader: (8)

fixored

Pads can turn to flaming dust past their MOT. Thats why its really important to know what the MOT is and what temps you are really seeing when tracking.

EVOBrakes

iTrader: (67)

I agree

So how does running a lesser compound increase life unless you brake less. Power/energy are unaffected by compound of course - you brake at a certain rate - you absorb a certain amount of power/energy. Unless you divert that elsewhere (rear?) or make less of it I would think a lesser pad would wear faster.

I certainly saw that when I ran HT-10's after I had gotten faster/added tire. They simply melted.

Smike

iTrader: (8)

I also agree. I would NOT run a lesser pad up front. Its still important to run r-coefs that are in line with each other. You can cause unstable braking doing that.

It will take longer to stop with lesser r-coef pads up front, thus build more heat (and wear faster).

EVOBrakes

iTrader: (67)

Ok - aside from empirical data - does time really matter?

From an energy standpoint - 120-45 MPH stop would create the same amount of heat (energy) regardless of the rate of decel. That's sophmore physics

From a power standpoint - 120-45 in say 2 seconds versus 4 seconds. Power to decel from 120-45 is same as accel from 45-120 taking out wind resistance for calculations sake. Obviously it takes MUCH more power to accel (or decel) that amount in 2 seconds versus 4 seconds. More power = more heat?

If we choose the power method....

So if that makes sense - than shorter harder stops would create more heat - I think yes - BUT - more time off the brakes increases airflow around the pad when it moves away from the rotor etc.

Which one wins.

In my opinion that's rhetorical - more power = more heat.

So now I know why I wear pads fast.

a) I run R compounds - tons of grip

b) I increase power - so terminal speeds are higher

c) I brake late and hard - but not late enough yet as my instructors say

c) I'm an average driver at best so my turn in speed is LOWER than a 'better' driver

That says that my braking events are

-High Power (thus high heat)

-Longish (I slow down more than I need to since I'm a wuss on track)

Smike

iTrader: (8)

Ok, more power = more heat. Correct energy would be the same, but time on the brakes to achieve that goal is what I was after. It will take longer on lower r-coef pads to do that 120-45 stop, longer on the brakes - more heat there is to build up. You have it with the time off brakes - you will then have a longer cooling period.

jid2

iTrader: (62)

There is wear, but the % vs a new pad is small. The Raybestos ST43's wear very nicely when ran at the proper temps.

Video of how the car is driven, on 265 BFG R1's....
http://www.vimeo.com/5365021

Evobrakes - you sound like a salesman, not everything you said is factual, or backed up with any sort of data...

Like this for example. I have temperature plots of the pad temp - but I'll keep those to myself for now.

EVOBrakes

iTrader: (67)

I am an engineer and a salesman - sometimes 1 gets in the way of the other.

I am off to ship - but I know what I'll be looking at later.

-Ken

EGbeater

iTrader: (35)

I understand what you guys are saying; however, my direct experience shows that my rear brakes on my Evo are doing next to nothing... in the track time it took to burn through TWO sets of trackworthy front pads (Hawk DTC-70, Carbotech XP12s, with cooling ducts going to them) there's been virtually no wear on the rear track pads at all.

I would agree that running a "lesser" front pad that will overheat/turn into dust faster than the rear would be a bad idea. What I'm suggesting, and hoping may be true, is that running a MORE AGGRESSIVE pad in the rear to shift some of the "work" towards the rear axle would help the front brakes not work as hard, as long as the front brakes weren't being pushed beyond their MOT as a result.

For this to work, I think, the front pads would have to have a high MOT (1600-2000), but also comprise a HARDER compound that would naturally have a lower coefficient of friction than the rears.

Maybe such an animal doesn't exist - a less grippy compound that still handles extreme heat. I've been told that brake pads capable of really strong decel by nature wear quickly and are friendlier to rotors because they utilize relatively-soft compounds to achieve their high coefficients of friction. But I have no idea if this is true; I'm neither an engineer nor an expert on brake pads.

Smike

iTrader: (8)

Sadly, most racing pad manufactures do not release their drag coefficients only qualifiers like med-high torque.

Do you have an IR gun? Next track day, IR gun all rotors and pads. See how big of a split there is from front to rear. With my Evo, I was seeing something like 900+ up front and 600s in the rear (right after the cool down lap - on HT10/GS5 pads, street tires).

But in the end, the fronts do a ton of work. Rears do not have the same friction area. And pads are consumables.