Brake Rotors: What are people using?

[fatbillybob]

But for someone like me who is nowhere near the limit of the car and simply getting practice in HPDE, I see no use for the crazy 2pc rotors. .

2 peicers aluminum hat and ring rotors are a simple no brainer upgrade even if only tracking occasionally.

Any 2pc will take 20lbs off rotating mass similar to gains the gt350r carbon wheels do for the R over regular gt350.

All 2pc rotors have quality metalurgy to handle the higher temps of track/race pads and superior engineered cooling so your pads, even street pads, will work better as a package.

The 2pc rotor rings are not much more than a quality 1pc rotor. Have you ever seen a 1pc rotor blow up? I do probably every other year. It isn't pretty and many racetracks have walls to hit.

AP is generally the best 2pc but I am very happy with stoptechs too. I can get 1.5 years of racing using xp20 pads on 3600lb car. My new favorite is the PFC V3 with rotor retention ring. You can change a ring out in 60 seconds! Brilliant system

2pc are called floating because there is about 10 thou play. It you hold the ring and shake the aluminum hat rattles. This can annoy street car owners but that 10thou is there for heat expansion and reduction in pad knockback, another performance feature of 2pc. The PFC V3 uses retention spring so under drive you get all the float but no noise. I think the V3 is best for dual use guys for this reason and killer for racers always in a hurry at the track. I use to have a back up set of rings/ rotors to swap at races. Now with 60 sec changes I just need a set of new rings for backup.

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[Ewheels]

I have updated the original list to include some new options and get rid of ones that were irrelevant (ie. drilled rotors, no one should be using those on track so why list them)

Couple new finds: I found out that Stoptech is a division of Centric. Also, I purchased Centric C-Tek rotors but I don't think they hold up well to heat. I'm noticing a fair amount of pad smear on the front rotors (getting too hot) and the rear rotor hats almost looked purple tinted from excessive heat. I think a 2 piece rotor would still be overkill for my skill level but I definitely need some higher carbon content rotors.

Does anyone know much about DBA rotors?

 

[TwinReverb]

2 peicers aluminum hat and ring rotors are a simple no brainer upgrade even if only tracking occasionally.

Any 2pc will take 20lbs off rotating mass similar to gains the gt350r carbon wheels do for the R over regular gt350.

All 2pc rotors have quality metalurgy to handle the higher temps of track/race pads and superior engineered cooling so your pads, even street pads, will work better as a package.

The 2pc rotor rings are not much more than a quality 1pc rotor. Have you ever seen a 1pc rotor blow up? I do probably every other year. It isn't pretty and many racetracks have walls to hit.

AP is generally the best 2pc but I am very happy with stoptechs too. I can get 1.5 years of racing using xp20 pads on 3600lb car. My new favorite is the PFC V3 with rotor retention ring. You can change a ring out in 60 seconds! Brilliant system

2pc are called floating because there is about 10 thou play. It you hold the ring and shake the aluminum hat rattles. This can annoy street car owners but that 10thou is there for heat expansion and reduction in pad knockback, another performance feature of 2pc. The PFC V3 uses retention spring so under drive you get all the float but no noise. I think the V3 is best for dual use guys for this reason and killer for racers always in a hurry at the track. I use to have a back up set of rings/ rotors to swap at races. Now with 60 sec changes I just need a set of new rings for backup.

Do you have a preferred dealer you use for the PFC V3 rotors?
I found the product information page, but don’t see known dealers.
https://pfcbrakes.com/News/ArticleID/31/NEW-Mustang-Parts-Available

 

[Norm Peterson]

Couple new finds: I found out that Stoptech is a division of Centric. Also, I purchased Centric C-Tek rotors but I don't think they hold up well to heat. I'm noticing a fair amount of pad smear on the front rotors (getting too hot) and the rear rotor hats almost looked purple tinted from excessive heat.

It's your pads that are getting overheated. Iron doesn't smear; pad compounds do.

HP+ is a pretty marginal pad for track duty (especially up front). Starts falling off by 800°F and is all done before hitting 1000°F. This is friction surface 'skin' temperature (where the melting/smearing happens), which runs hotter than bulk mean pad temperature.

Norm

 

[shogun32]

HP+ is a pretty marginal pad for track duty

do you have the original URL? I'm curious what HP is referring to as the 'OEM' pad or they are just picking a representative street pad example from who knows where...

 

[Norm Peterson]

do you have the original URL? I'm curious what HP is referring to as the 'OEM' pad or they are just picking a representative street pad example from who knows where...

That one's been around a while, so I don't know. But here's some mu vs temperature curves for Ferodo pads (note that temperatures are given in °C (which you'd multiply by 1.8 to get a close approximation of the °F temperatures). Aren't the PP level pads DS2500 or comparable? If so, what Hawk shows for OEM is at least representative of 'base'.

Norm

 

[Ewheels]

It's your pads that are getting overheated. Iron doesn't smear; pad compounds do.

HP+ is a pretty marginal pad for track duty (especially up front). Starts falling off by 800°F and is all done before hitting 1000°F. This is friction surface 'skin' temperature (where the melting/smearing happens), which runs hotter than bulk mean pad temperature.


Norm

True. I see how my post's wording made it target rotors as the culprit over the pads. I understand that it's the pads getting over heated and smearing onto the rotors but my thought was that it was caused by the rotors getting too hot and transferring the heat to the pads.

Question for you though and I can't seem to get an answer from others I have asked. So these C-Tek rotors are deemed cheap and insufficient by forums geniuses and that higher carbon content rotors would work better. So the higher carbon content rotors would withstand the heat better but would theoretically see the same temperatures right?? So if the rotors are seeing the same temperatures, whether cheap rotors or more expensive ones, and that high temperature is transferring to the pads and the overheating pads are the problem, why get high carbon rotors??

 

[Ewheels]

Though as others have pointed out to me, I don't think the pads are actually getting overheated. I think I'm not letting them warm up properly and they are depositing excessive pad material. So not an overheating issue, but a user issue

 

[fatbillybob]

So if the rotors are seeing the same temperatures, whether cheap rotors or more expensive ones, and that high temperature is transferring to the pads and the overheating pads are the problem, why get high carbon rotors??

I don't think it matters for stopping power. It matters in durability. The best rotors all have heat check cracking with use. Cheaper rotors get this faster than others. You change rotors when those cracks meet the outside radius of the rotor. On a good rotor that is 1 year of racing for me. That's why you don't track drilled rotors because they are too easy to get those cracks to conjoin where holes meet and then the rotor cracks and can fail. When we raced C5 corvettes and our rules made use stock brakes we cracked the rotors in 3 race days and that was only 2 or 3 sessions per day sprint racing/qualifying/practice. Then when a racer got airlifted at Runoffs the club allowed aftermarket brakes of higher heat capacity (bigger thicker rotors). Good brakes are a huge safety issue.

If a brake system is marginal for your purpose then you need a higher quality rotor, better fluid, better pads. Sometimes you only need 1 or none of those things. For my S550 is SCCA clubracing in a near stock class 3600lb and 50mm intake restrictor I still need 2 piece rotors from a quality maker (PFC) and highest heat range carbotech race pad XP24, removed spindle plate to let more air to rotor but using cheap Valvoline synthetic brake fluid with a relatively low dry boiling point. The stock DS2500 pads melted on my stock rotors in 2 sessions at WSIR a not brake intensive track. Getting pad smear is not a problem. You put more aggressive pads on and run them like you are bedding brakes and al the old stuff comes right off. Brake judder is a sure sign of bad pad transfer and that comes from overheating pads on rotors. So far the few times I have had pad judder I have always been able to clean the rotor with a more aggressive pad.

I think the stock rotors are good just heavy as heck. I would not run a stock type rotor just to get the 20lbs off the wheels. But if someone wants to run solid oem rotors that's fine just use a race pad for the track. Even if a guy is slow the mustang is nearly 4000lbs and that weight alone makes heat.You need more pad to handle that.

 

[fatbillybob]

Though as others have pointed out to me, I don't think the pads are actually getting overheated. I think I'm not letting them warm up properly and they are depositing excessive pad material. So not an overheating issue, but a user issue

If you are getting pad transfer judder on track with stock DS2500 pads and stock oem type rotors you are smearing the pad by overheating the surface. I've had 2 session on track with the stock pads and I was extremely underwhelmed. I think I posted some pics somewhere of the pad material literally flaking off but the side effect is the rotors have zero wear just some pad smear to rub off with a decent pad.

 

[Norm Peterson]

Question for you though and I can't seem to get an answer from others I have asked. So these C-Tek rotors are deemed cheap and insufficient by forums geniuses and that higher carbon content rotors would work better. So the higher carbon content rotors would withstand the heat better but would theoretically see the same temperatures right?? So if the rotors are seeing the same temperatures, whether cheap rotors or more expensive ones, and that high temperature is transferring to the pads and the overheating pads are the problem, why get high carbon rotors??

There has to be a compromise going on. High carbon iron is very likely more resistant to wear from pads that work via abrasive friction (semi-metallic and ferrocarbon formulations), and also more likely to form cementite when it is severely heated. Cementite is a harder form of iron, think hard spots that resist machining and wear even slower (and the brake judder / disc thickness variation / rotor "warpage" effect returns).


Norm

 

[Norm Peterson]

Though as others have pointed out to me, I don't think the pads are actually getting overheated. I think I'm not letting them warm up properly and they are depositing excessive pad material. So not an overheating issue, but a user issue

You may not be bedding them properly/fully. But that's not the same thing as not letting them "warm up properly", at least not once bedded in. I'm assuming that at least the out lap is being used as a 'warm-up' lap for everything in the car that needs some warming up; that you're not charging into the first braking zone out of pit lane at 10/10ths.

The only way you're going to get excessive pad material transfer is with pad friction surface temperatures beyond what the compound is rated for. Not only would you be running the 'skin effect' temperatures higher; you'd be extending the over-temperature region deeper into the pad material affecting pad mechanical strength further below the surface.

Terry Fair has a reputation for being harder on brakes than most people. Just sayin'.


Norm

 

[kz]

I think the stock rotors are good just heavy as heck. I would not run a stock type rotor just to get the 20lbs off the wheels. But if someone wants to run solid oem rotors that's fine just use a race pad for the track. Even if a guy is slow the mustang is nearly 4000lbs and that weight alone makes heat.You need more pad to handle that.

Do you by any chance have weights of OEM / aftermarket rotors ?

 

[Ewheels]

I love these technical discussions.

Let's objectively clarify some things. So my problem is brake judder under hard braking into turns. Some visual things I've noticed: the front rotors look dark gray on the surface and hazy. The rear rotors "hats" near the mounting hub looked to be slightly purple, suggesting they got very hot.

The possible root causes for the brake judder are:
1. Improper bedding - this could be the problem but I don't believe it is. I followed the manufacturer's instructions
2. Uneven / excess pad deposits due to overheated pads - I don't think this is the problem as the GLOC R12 pads are rated up to 1860°
3. "Hot spots" in the actual rotors due to overheated rotors - I think this is the issue. As rotors act as a heat sink for the braking system, if they are receiving more heat than they can reject AND the material is more prone to sporadic hardening, this seems like a recipe for brake judder

 

[Norm Peterson]

The rear rotors "hats" near the mounting hub looked to be slightly purple, suggesting they got very hot.

This part sounds like either traction control or AdvanceTrac has been working overtime.


Norm

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