[TrackClub]

Originally Posted by Mountain

I want to circle back and add to this due to my experience with stock pad wear and use:

Did a SCCA Time Trial this weekend. My front pads were at around 7.5mm before leaving for the event. I bought an extra set of front pads just in case (glad I did) as I wasn’t sure I had enough for the entire event; the event consisted of:
Day 1 = two 20-min practice sessions and two 20-minute time trial sessions
Day 2 = three track sprint laps and two 20-minute time trial sessions

At the end of the first 20-minute time trial session, on Day 1, I had to be very cognisant on what I was doing with my braking otherwise I’d start to loose brake force mid-braking. I ran the car no problem the second 20-minute time trial session without issue, making sure my braking was as efficient as possible. I decided to swap to the other set of pads I bought (OEM replacement Ferodo). Upon measurement of the old pads, I found all four with [normal] taper wear, top to bottom (largest to smallest piston contact area). Measurements went something like this (top to bottom): 4.80mm-4.95mm-5.40mm.

Zero brake issues with the fresh pads in throughout Day 2. Fresh pads were 9.65mm pad material thickness.

Weather was sunny, humid and 85F. Track was Gingerman - not a track too hard on brakes, but not easy on them.

Main point: When you check pad material thickness, at a minimum, check at the portion to the top (most wear).

Second point: I would heavily caution running a track day (1 day/four 20-minute sessions) on pads with under 6mm of pad material left unless you understand how to be efficient with your braking and/or the track is not harsh on brakes. OR (unlikely) if you’re not going to run near at least 8/10ths... Furthermore, I would say to not risk running a track day starting with 5mm or under of pad material, period.

Interesting observations. When you refer to "brake force" do you mean fade? How old were your tires?

I have 4 days on mine now, they are about 50% done and i would not hesitate to do another 4x30min day on them, if not 2 (venue dependent). In either case, it is always a good idea to check tires and brakes et al in between each run. I find stockers wear very evenly for me. When I tried XP10s my RF wore out much faster for some reason.

Always good to share info on these subjects to thx for posting. Cheers!

[Mountain]

Originally Posted by TrackClub

Interesting observations. When you refer to "brake force" do you mean fade? How old were your tires?

I have 4 days on mine now, they are about 50% done and i would not hesitate to do another 4x30min day on them, if not 2 (venue dependent). In either case, it is always a good idea to check tires and brakes et al in between each run. I find stockers wear very evenly for me. When I tried XP10s my RF wore out much faster for some reason.

Always good to share info on these subjects to thx for posting. Cheers!

Yes, the brakes just started to exhibit some fade. I didn’t want to use “fade” as that word tends to translate to “the brakes are 100% gone to some”. I started to get some fade at the end of high speed straights. A slight adjustment to my braking was all that was needed, but I felt, with the outside temps and two hard braking zones one after the other, I was riding the edge of the pads tolerance.

I feel I could have still used the pads for the two more sessions the next day, but my point is probably not everyone could manage that and, for me, why worry about it if I had a set of fresh pads.

The taper wear I found on all four (4) pads. All exactly the same type of taper trend. Easy to miss if you’re not careful with taking measurements.

Front tires were brand new for the event SC3’s and the rears were original to the car tires with 4 other track events, 2 autox and about 10k miles on them. I killed the insides on my original fronts due to slightly excessive toe - the rest of the tire had enough meat for this entire event otherwise. Rear tires are still good for another event. So, for me, looks like 5-6 events on fronts and 7 events on the rear - pretty in line with the word of everyone else.

BTW, I run SS track air deflectors and the SS track/ZL1 rotor shields. StopTech 600 fluid.

[TheRealJA105]

Originally Posted by Mountain

BTW, I run SS track air deflectors and the SS track/ZL1 rotor shields.

Finally someone smart enough to do this for the $30 or whatever they cost and not just say the 1LE doesn't need them. If I had a ZLE I'd be buying them too.

[artey34]

Originally Posted by TrackClub

Previously used pads: not at all. Brand new pads: yes, as you dont want to heat shock them, which could cause glazing. You could easily do it on an access road, or even on track (by braking for the first 6-8 corners lightly, then 2-3 corners hard, then park the car and let them cool down for a bit (30mins is good enough).

Buying a set that is slighly used. So same material as what mine are because they are stock, but never been on my car exactly. So best off swapping them at the track, then doing a few heat cycles before jumping on the track with them?

I want to use as much of the material as I can, so this leads to changing pads at the track once they get low. 5mm is the lowest I would start a day with, but a full day (7 20 min sessions), I will need to swap them out

[TrackClub]

Originally Posted by artey34

Buying a set that is slighly used. So same material as what mine are because they are stock, but never been on my car exactly. So best off swapping them at the track, then doing a few heat cycles before jumping on the track with them?

I want to use as much of the material as I can, so this leads to changing pads at the track once they get low. 5mm is the lowest I would start a day with, but a full day (7 20 min sessions), I will need to swap them out

Yep, that's what id do exactly, but not heat cycles per se, but a bedding procedure (just to avoid any misunderstanding).

[TrackClub]

Originally Posted by Mountain

Yes, the brakes just started to exhibit some fade. I didn’t want to use “fade” as that word tends to translate to “the brakes are 100% gone to some”. I started to get some fade at the end of high speed straights. A slight adjustment to my braking was all that was needed, but I felt, with the outside temps and two hard braking zones one after the other, I was riding the edge of the pads tolerance.

I feel I could have still used the pads for the two more sessions the next day, but my point is probably not everyone could manage that and, for me, why worry about it if I had a set of fresh pads.

The taper wear I found on all four (4) pads. All exactly the same type of taper trend. Easy to miss if you’re not careful with taking measurements.

Front tires were brand new for the event SC3’s and the rears were original to the car tires with 4 other track events, 2 autox and about 10k miles on them. I killed the insides on my original fronts due to slightly excessive toe - the rest of the tire had enough meat for this entire event otherwise. Rear tires are still good for another event. So, for me, looks like 5-6 events on fronts and 7 events on the rear - pretty in line with the word of everyone else.

BTW, I run SS track air deflectors and the SS track/ZL1 rotor shields. StopTech 600 fluid.

Thx for the extra info. Yep maybe a very slight and temporary fade on very hard venues, but nothing that cant be very easily adjusted for without affecting overall pace. I find that the type of initial brake application has a lot to do re making all 4 tires working under braking.

I run my car bone stock and i am extremely happy with it, so gotta ask: why rotor shields? What purpose do they serve heat management wise?

Thanks!

PS BTW i am completely of the same opinion, that if spare pads are available, zero point pushing the envelope on hard runs. I will check the measurement of my pads tomorrow to see of they run a similar taper to yours.

[Mountain]

Originally Posted by TrackClub

Thx for the extra info. Yep maybe a very slight and temporary fade on very hard venues, but nothing that cant be very easily adjusted for without affecting overall pace. I find that the type of initial brake application has a lot to do re making all 4 tires working under braking.

I run my car bone stock and i am extremely happy with it, so gotta ask: why rotor shields? What purpose do they serve heat management wise?

Thanks!

PS BTW i am completely of the same opinion, that if spare pads are available, zero point pushing the envelope on hard runs. I will check the measurement of my pads tomorrow to see of they run a similar taper to yours.

The SS track/ZL1 shields are basically just tie rod shields: there really isn’t any material covering the rotor. The stock SS 1LE shields still cover around 25% of the rotor.

[TrackClub]

Originally Posted by Mountain

The SS track/ZL1 shields are basically just tie rod shields: there really isn’t any material covering the rotor. The stock SS 1LE shields still cover around 25% of the rotor.

Live and learn Thank you!

[TrackClub]

Checked my pads and Mountain man is correct: a very slight taper top vs bottom. Also, my F pads are done after 4 hard days. So are both front tires (corded on the inside) after 5 days.
But happy with relatively even wear with slightly more wear on the inside at 2.6 camber.
Note to anyone heading to Calabogie: the track is super fun, but very hard on tires (abrasive surface given original asphalt has receded quite a bit).

[cdrptrks]

Originally Posted by cdrptrks

Here is one of my front rotors at slightly over half of the thickness used. The heat checks feel like bumps when dragging my fingernail along the rotor but they don't snag my fingernail. None of them are all the way to an edge either. They looked/felt similar when I bought the car last year and I added 5 track days since then on stock Fedoro pads.

Originally Posted by TrackClub

If they are down 1mm thickness wise, plus the sheer number and wide area of heat checks (albeit still small) i would start thinking of ordering a new set to have it handly.

Update: my front rotors lasted about 2 more years after that picture was taken for a total of about 30 track days plus lots of street driving (mostly highway) over about 3 years mostly on stock pads (and some time on StopTech Sport pads which were similar but a bit less tolerant to heat) but I was bringing a spare set of new rotors with me to track days as a precaution. The calipers I was using to occasionally measure the rotor thickness didn't have enough of a notch to clear the outer lip the last few times I measured and I couldn't tell with the wheel on the car so I accidentally ran them to a final thickness of 31.2mm and 31.5mm, significantly below the 32mm discard thickness. I do NOT recommend this. I would have likely missed any remaining sessions for the day if I found a cracked front rotor at the track because of how stubborn the caliper bolts are, which I didn't know about beforehand. Not to mention that complete rotor failure would likely damage the car and could cause a crash.

The rotor actually cracked to the inside towards most of the hat bolts on the thinner rotor and 1 of the 10 hat bolts on the thicker one which surprised me since I was looking for and expecting cracks to the outside. The cracks were difficult to see unless you looked very closely and they were much more noticeable from the back side after I removed the rotor. I never had the rotors "turned" so there was a big lip on the outside; not sure if that is related to how they cracked. I felt a slight vibration under braking during my last session before I noticed the cracks (and I was checking several times per track day). I was driving on ZLE wheels with 100 treadwear SC3R tires (with cooldown laps in between hot laps) for a few sessions at the time which was probably heating up the brakes more than the stock tires do. I was able to drive home a few hundred miles on the highway before replacing the rotors without any issues although I used more engine braking than normal as a precaution.

I attached a picture of the most severe crack as seen from the front and back of the rotor. Some of the less severe cracks were shorter and went up to the bolt but not past it when viewed from the back.

[cdrptrks]

Today I finally got around to using my Dremel to notch a pair of plastic Harbor Freight calipers (see picture below) so that they can clear the lip of the rotors for accurate thickness measurement in the future. Going forward I plan to use these for checking rotor thickness along with pre track day visual inspection of the back of the rotors (using a flashlight) with the front of the car on ramps. This will hopefully be easier now since I removed the stock metal SS 1LE rotor splash shields and replaced them with the smaller track splash shields when I replaced the rotors.

Most of the cracks looked like this from the front:

[cdrptrks]

Originally Posted by TrackClub

Checked my pads and Mountain man is correct: a very slight taper top vs bottom.

I am seeing the same thing on stock tires with stock pads but the top wears noticeably more than the bottom of the rear pads when I use 100 treadwear SC3R tires on ZLE wheels with stock brake pads and I can also consistently smell the brakes in the braking zones on fast laps with those tires which is not usually the case with the stock SC3 tires. The rear StopTech Sport pads I was running the first time I tried the SC3R tires are less heat resistant and they tapered so badly that they needed to be replaced after just 2x 20 minute sessions!

[TrackClub]

Wow dude! That's likely at least a year, or 10 days too late.
Those cracks on the hats are SUPER SCARY and that's how rotors come off and take your wheel with it. Been there seen it and it is uber scary to witness at speed. Heat check cracks on a rotor are one thing, but cracks on a hat are a completely different level!!! Thanks for posting the pix and hope the memebers will take a close look at those as exampless of CRITICAL failures. You see one of those: do not drive your car never mind track it. BTW, that's why i like to replace complete assemblies, that come with brand new hardware vs buying new rings only - just as an aside. Cheers and play safe!

[TrackClub]

Wow dude! That's likely at least a year, or 10 days too late.
Those cracks on the hats are SUPER SCARY and that's how rotors come off and take your wheel with it. Been there seen it and it is uber scary to witness at speed. Heat check cracks on a rotor are one thing, but cracks on a hat are a completely different level!!! Thanks for posting the pix and hope the memebers will take a close look at those as exampless of CRITICAL failures. You see one of those: do not drive your car never mind track it. BTW, that's why i like to replace complete assemblies, that come with brand new hardware vs buying new rings only - just as an aside. Cheers and play safe!