Unable to measure pad thickness; would you leave these on?

[dparm]

My current living arrangements don't really permit me to be removing the wheels and measuring pad thickness, the best way to determine pad wear. I have another track day at GingerMan coming up in about 2 weeks.

The two photos below show about 1,000 miles of street driving and two track days (one of which was 95 degrees). I am thinking these pads are fine for at least one or two more track days. Agreed?

Apologies for potato photo quality, but it's tough to photograph these with a flashlight in one hand in a dimly-lit garage.

[jphughan]

Absolutely! Those pads have a huge amount of material left. If that's an endurance compound, you probably have another 6 track days left in them, give or take. Most race pads can be run basically down to the backing plate, though Pagids are a notable exception in that from what I've read, after half the material is gone, the performance drops significantly.

But next time, maybe make it easier on yourself and others by briefly parking somewhere outdoors during the day for the photo op.

[macdude357]

Originally Posted by dparm

My current living arrangements don't really permit me to be removing the wheels and measuring pad thickness, the best way to determine pad wear. I have another track day at GingerMan coming up in about 2 weeks.

The two photos below show about 1,000 miles of street driving and two track days (one of which was 95 degrees). I am thinking these pads are fine for at least one or two more track days. Agreed?

Apologies for potato photo quality, but it's tough to photograph these with a flashlight in one hand in a dimly-lit garage.

What I do is hold a ruler against the rotor and a pick of that with my phone (holding it against the rotor as well). (I have EC7's that I can fit the ruler in between one spoke and the phone in between another).

That will give you a good idea how much pad is left without taking the wheel off.

[dparm]

Originally Posted by jphughan

Absolutely! Those pads have a huge amount of material left. If that's an endurance compound, you probably have another 6 track days left in them, give or take. Most race pads can be run basically down to the backing plate, though Pagids are a notable exception in that from what I've read, after half the material is gone, the performance drops significantly.

But next time, maybe make it easier on yourself and others by briefly parking somewhere outdoors during the day for the photo op.

Good tip, but sometimes you get weird shadows. I also didn't want to lose my spot in the garage.

They're not an "endurance" compound, FWIW. Because of that, I plan to pull them once they get below 25%.

[jphughan]

Originally Posted by dparm

They're not an "endurance" compound, FWIW. Because of that, I plan to pull them once they get below 25%.

Ah yes, forgot you were running StopTech Street Performance pads. In that case I'd say you have at least 2 days left on those, maybe 4 depending on the track and your driving. So I'd say buy your next set of pads now and take them with you to the track boxed up in case you need to quickly swap them in (easy with that BBK), but definitely don't write those off this early.

[nholmes]

They look pretty thick still, dude. Not sure of how aggressive you are with your braking but those most certainly have a track day or two left in them.

[dparm]

Originally Posted by jphughan

So I'd say buy your next set of pads now and take them with you to the track boxed up in case you need to quickly swap them in (easy with that BBK), but definitely don't write those off this early.

That was my plan -- don't want to get into a situation where the pads disintegrate and I have to either sit out the rest of the day, or try to drive home by only using rear brakes.

[Cloud9blue]

Easier and more accurate way to check pad thickness is to take the wheels off and look at the pads from the caliper opening from the outside (where you drop the pads into the caliper when switching pads). That way you can see the inner pad as well. Depending on the airflow to the caliper, your inner pad might wear faster than the outer ones.

[swftiii]

Agreed - there seems to be plenty of pad left for now. I have always gone to new pads once the pad material and the backing plate are about the same thickness. Yes, theoretically you can run them down farther, but without being able to see the inside pad and the reduced heat dissipation, I am not willing to take that risk. I had a buddy that ran his down to the backing plate (the inside wore faster than the outside, so he couldn't see it) and stuffed his Porsche 993 TT into the wall.

I don't skimp on brakes or tires as they are what keeps the car on the race surface and the shiny side up.

-Skip

[Richbot]

Originally Posted by swftiii

Agreed - there seems to be plenty of pad left for now. I have always gone to new pads once the pad material and the backing plate are about the same thickness. Yes, theoretically you can run them down farther, but without being able to see the inside pad and the reduced heat dissipation, I am not willing to take that risk. I had a buddy that ran his down to the backing plate (the inside wore faster than the outside, so he couldn't see it) and stuffed his Porsche 993 TT into the wall.

-Skip

This is a good rule of thumb which I use as well even for street cars.

[jphughan]

Originally Posted by swftiii

Agreed - there seems to be plenty of pad left for now. I have always gone to new pads once the pad material and the backing plate are about the same thickness. Yes, theoretically you can run them down farther, but without being able to see the inside pad and the reduced heat dissipation, I am not willing to take that risk. I had a buddy that ran his down to the backing plate (the inside wore faster than the outside, so he couldn't see it) and stuffed his Porsche 993 TT into the wall.

I don't skimp on brakes or tires as they are what keeps the car on the race surface and the shiny side up.

-Skip

Agreed. And to be clear, I would only run lads down close to the backing plate if I were using pads that were known to perform even at that low thickness AND had also checked the inside pads.

[dparm]

What would cause the inside pad to wear so much faster?

[macdude357]

Originally Posted by dparm

What would cause the inside pad to wear so much faster?

Cloud9blue Mentioned that in his post above:

"Depending on the airflow to the caliper, your inner pad might wear faster than the outer ones."

[jphughan]

Originally Posted by dparm

What would cause the inside pad to wear so much faster?

Unless you have ducting (which the E9x doesn't), you have higher temperatures farther inboard and less ability to evacuate air through the wheel openings relative to the outboard pads.

[dparm]

Originally Posted by jphughan

Unless you have ducting (which the E9x doesn't), you have higher temperatures farther inboard and less ability to evacuate air through the wheel openings relative to the outboard pads.

Thanks. I was under the impression that the ST40 calipers are designed to channel air towards the pads? It's referenced in the installation guide. Is it just not very effective?

[jphughan]

Originally Posted by dparm

Thanks. I was under the impression that the ST40 calipers are designed to channel air towards the pads? It's referenced in the installation guide. Is it just not very effective?

For all I know, it's plenty effective. But if you don't have as much air getting to the brake area in the first place, then you just have great channeling for not enough air.

[okusa]

Originally Posted by dparm

That was my plan -- don't want to get into a situation where the pads disintegrate and I have to either sit out the rest of the day, or try to drive home by only using rear brakes.

Just bring a new set to the track so you are never in that situation. Worst case you miss a session while waiting for everything to cool down.

[Cloud9blue]

Originally Posted by dparm

Thanks. I was under the impression that the ST40 calipers are designed to channel air towards the pads? It's referenced in the installation guide. Is it just not very effective?

Don't buy into the marketing. No caliper can re-direct airflow without proper brake duct or scoop, which this car doesn't have.