when do you replace a race pads with no wear indicator ??

[azev]

When do you guys normally replace your track day pads (GLOC R12 in my case) ?? I didn't realize my track pads are worn to 6mm when I put them on today for tomorrow track day. My stock oem pads have about the same pads material left and I am taking them with me just in case I spent all my track pads tomorrow.

I guess my questions is, is there a good guidelines for how low can you go on a track pads such as GLOC or Raybestos ??
Can you wear it down close to the backing plate ??

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[BmacIL]

When do you guys normally replace your track day pads (GLOC R12 in my case) ?? I didn't realize my track pads are worn to 6mm when I put them on today for tomorrow track day. My stock oem pads have about the same pads material left and I am taking them with me just in case I spent all my track pads tomorrow.

I guess my questions is, is there a good guidelines for how low can you go on a track pads such as GLOC or Raybestos ??
Can you wear it down close to the backing plate ??

I would not want to start a track day with less than 6 mm, and I would advise not doing another on that set after this track day. You'll probably have 1-2 mm of pad left after, which is for all intents and purposes: spent. It really depends on the track, though. For a track that's not hard on braking you could maybe get more, but many organizations would not let you on track with much less than that.

 

[Norm Peterson]

When do you guys normally replace your track day pads (GLOC R12 in my case) ?? I didn't realize my track pads are worn to 6mm when I put them on today for tomorrow track day.

When the friction material gets below 50% of its original thickness. Tech inspection should require that much to be present. Do you know how thick your pad friction material started out at? How many track days did it take to get down to 6mm? If they started out at 11mm and you've got at least two track days on them you're probably OK for a carefully driven day (I'm in no way guaranteeing that, honestly you'd be in much better shape if it took 3 or 4 track days to get them down to 6mm).

I guess my questions is, is there a good guidelines for how low can you go on a track pads such as GLOC or Raybestos ??

Tech inspections use that 50% guideline for reasons that ought to be based on some experience. Obviously this is at the beginning of the day, so there are some assumptions being made regarding wear rates.

Can you wear it down close to the backing plate ??

It'd be a really bad idea to knowingly do so. It's not just you and your car that would be placed at increased risk.

It's something of a 'hidden' track day expense that you don't get to use as much of the original pad thickness as you can in street-only driving.



On edit, pads with wear indicators are there for street use purposes only. Do not use them as your limit for track use going into a session even if you're tracking on pads that have them.


Norm

 

[NightmareMoon]

My understanding is that the 50% life guideline isn’t only so that you don’t run out of pad material, but also that the pads have less thermal capacity and transmit more heat to your brake fluid and calipers if they’re low on material, so overheating the brake system is more likely when the pads get low. I’m not an automotive engineer, so IDK how true that aspect is.

 

[PoppinJ]

My understanding is that the 50% life guideline isn’t only so that you don’t run out of pad material, but also that the pads have less thermal capacity and transmit more heat to your brake fluid and calipers if they’re low on material, so overheating the brake system is more likely when the pads get low. I’m not an automotive engineer, so IDK how true that aspect is.

This is true but with high quality brake fluid shouldn't be much of a concern. It takes A LOT to boil Motul 660 or Castrol SRF. Still overall better to have more pad though.

I've pushed my pads one track day to far and almost really regretted it. One of my rears was basically nothing but the metal backing plate and starting to score my rotor. Obviously this is extreemly dangerous as you run around the race track and could have damaged my 2 piece rotors as well.
Now I throw a lot more pad material away if I feel like it might even be a little close so that that doesn't happen. I've got a box of used "emergency" pads that have a couple mm of material on them that I take to the track with me now. But do you really wanna be changing brake pads out at the track? No.
Like someone was saying, you learn how fast they wear. I'm more comfortable going into a track night in America event with 3 20 min sessions with low material pads than my other clubs where I run 5 30 min sessions.
This sport is dangerous and expensive, error on the side of caution.

 

[BmacIL]

My understanding is that the 50% life guideline isn’t only so that you don’t run out of pad material, but also that the pads have less thermal capacity and transmit more heat to your brake fluid and calipers if they’re low on material, so overheating the brake system is more likely when the pads get low. I’m not an automotive engineer, so IDK how true that aspect is.

There's definitely truth to this. There's less thermal mass. This can be mitigated by things like Ti backing plates, and of course, good fluid. The other is using a pad that's a good match to the tire you're using regarding friction coefficient at temp. Too low and you'll be on the brakes significantly longer, which means even if they don't fade, you'll get more heat transfer into the caliper (even if the total energy is the same).

 

[Radiation Joe]

There is also the issue of pads crumbling when they get worn down. Hawk Blues were notorious for this and I have first hand knowledge going into 10 at Thunderhill with almost nothing to slow me. My rule of thumb is replace if much less than 50%.

 

[azev]

Hi Guys thanks for the reply and feedback; so I came home safely from the track with probably 2-3mm left on the pads after yesterday track day. However like NightmareMoon said regarding Thermal capacity, I feel like the brake isnt doing as good as a job compared to when they were new. There had been a few case where I am getting fade on the brake even with titanium backing plates. I dont remember ever having this problem prior to yesterday track day event.
The other thing I have problem with going to the track with just enough pad materials is "piece of mind", I felt very insecure that something bad could happen, and I was driving 1-2sec slower than my normal average.
Maybe its a combination of many things, but I've decided to buy 2 sets of new pads and keep one in my track toolbox from now on

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