92C2Targa#119

Question about brakes and pad wear.
What is the minimum that a guy would let the pads wear too before swapping out to new pads. Note : without changing rotors with pads.

I believe the sensors go off at ~2 mm.

Would it be 4 mm or 5 mm. I know it depends on lots of things, but those that change their pads regularly between track time etc, must have a general rule they use for pads and even rotors?

I appreciate your responses.

Cheers

Iceter

If your question is geared towards avoiding replacing your rotors, then pad wear in daily driving is irrelevant. The rotors on these cars are soft and somewhat sacrificial. Swapping out brake pads early will not keep your rotors from wearing and requiring either turning or replacing.

In fact, I considered having my rotors turned before my brake pads required replacing because of the wear on the rotors. But, I didn't notice any deterioration in my ability to stop so I put it off until the pads were gone.

Also, the sensors are inexpensive and soft, so there is no additional wear on the rotors from allowing the pads to wear down to the sensors and allowing the car to tell you when the pads need to be replaced. You will still have many miles of safe driving on the pads even after the sensors touch the rotor--unless you are aggressive with your braking. So, allowing the sensors to do their job is no big deal.

When I swapped pads and rotors, I waited until the sensors alerted me (although I'd been watching the pad depth for a while beforehand). When I removed the pads, they were worn to the point where I was not alarmed by how little friction material I had left, but if I had seen them at that point without the sensors alerting, I would have still replaced them--in a nutshell, the sensors alerted me at just the right time.

If your car is used on the track, then I defer to those who track their cars and can tell you how much friction material they go through in a day of hard driving.

3Series

Most clubs and PCA DE tech sheets recommend replacement at 50% wear. (that's a high safety margin)
The last thing you want is to start a sessions with 20% left, have a Mario Andretti moment and drive the crap out of the car and notice that all the pad material is gone while going 115mph on a straightaway with a grove of 50yr old trees at the end of the track.....

Wear rates for pads on the track depends on the pad brand/material, track you are driving on and driver skill level.

92C2Targa#119

Thanks I thought 40-50 % would be the norm.

JCGMS

What is 100% on stock pads?

mgordon18

Change your pads when the pad thickness is less than the thickness of its metal backing plate.

3Series

No one actually measures the pad material. It's a visual check. If you've been around pads long enough, you'll know what a new pad looks like (thickness) and when it's about half way done. This is at the track.

For normal driving, do the porsche pads squeal when they wear out like many other pads on other makes?

92C2Targa#119

I believe it is 10 mm

NIACAL4NIA

Majority of new brake pads are 12mm and once they reach 2mm it's a good time to replace before the brake warning sensor brakes.

Macster

Unless the 997 model brakes are different the wear sensors are approx. 3/16th of an inch (or 0.187" in diameter which is over 4.7mm (0.03937" per millimeters).

Thus when the wear sensor light comes on that's a good time to change the pads and probably the rotors too.

You can I guess continue to drive the car after the wear sensor light comes on. I did once putting maybe another 1K miles on the car but at the end the brake wear warning light was on all the time and I found it distracting so I broke down and did the brakes.

For any track events you will have to consult with the rule book or track guidelines or fellow enthusiasts.