MikenOH

Has anyone with PTV on their 991 experienced more pad wear on the rear brakes vs. the fronts either in daily driving or at the track?
I ask since on planet 9 there is some discussion on this topic given how the PTV would seem to engage the rear brakes more at the track than a non-PTV car.
thanks for any help.

John's 991

I have noticed very high rear brake temperatures on the track when not using Sport Plus which I'm sure would equate to additional wear eventually. With Sport Plus on the rotor temps front in back were both around 500 degrees. With it off the rears were about 50 degrees higher.

chuck911

Uh.... when you figure out what it was that you really meant to say, can you also let us know when (how soon after coming off the track) you took your temps?

John's 991

Lol, thanks, made an edit. And about 1 to 2 min using a laser pyrometer.

MikenOH

John--is it fair to say you have not visually noticed any increased wear on your rear pads, relative to the fronts? How many miles/track days?

SB

I was also wondering about that. I think you should see something well in excess of 1000 at the end of a 25-30 minute track session if the car is driven hard.

chuck911

And if PTV is the subject, then wouldn't it be nice to know the RIGHT and LEFT rear brake temps?
PTV works to help rotate the car by applying a small braking force to the inside rear. So in general wouldn't we expect to find higher left rear brake temps on tracks run counterclockwise? And vice versa?
Related point, PTV uses controlled braking to help turn the car. But this doesn't necessarily have to result in actual braking. More often the braking force results only in reduced power to the wheel. This could easily result in one driver, who habitually uses too much throttle while cornering, having much higher rear temps than another driver who makes better use of throttle control and weight transfer in cornering. In other words, the more the car has to help correct the driver the more PTV comes into play and the hotter the brakes are bound to get.

John's 991

Chuck, I wore out the brake pads after 4-5 track days at 2,800 miles. Wear was very even front to back. The rear brakes get very hot, to the point of smelling when not in Sport Plus (I forgot one session, but I had the pyrometer). It is likely that was more aggressive traction control than PTV.

I have not noticed temp differences from side to side. Surprisingly to me though was that the rear temps are often a little higher than the fronts. I figured the fronts do way more work, but they are bigger and maybe better ventilated so maybe cool faster.

Also temps were taken 1-2 min after coming off the track AFTER a cool down lap. I was not particularly focused on brake temps so did not come straight in to measure.

trysixty

this may be completely unrelated but when my car was in to have sport design and PSE installed they replace rear brake pads on a recall or supplier problem according to dealer

Mrok

Hi gays, i am having The same problem héroe, 2013 991C2S X51, i nave to change The rear brake pads after 1500 miles of 60%track and 40% street use.
Is that normal?...

Bacura

Many of the electronic handling aids use selective braking. Imagine full acceleration with one rear brake engaged. That would get very hot with excessive wear. I always thought for the track all traction control electronics should be turned completely off for max brake wear. I believe in a GT3 more can be turned off than in a standard 991.

Dyim

With the engine out back, it should keep things hot back there also.