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Cheap Rotors are Best Rotors - Change my Mind (Raybestos R-Line vs other rotors)

Duane Black

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So since I started my track career, I came to a conclusion I have two ways of handling the brake rotor dilemma. Expensive rotors may last a long time, but ultimately of course, are expensive. Alternatively, I can find cheap rotors, and just count on replacing them often. I can put on 10 $40 rotors and may get as much or more life out of that as I will a single $400 rotor. As an idiot who drives the car on the street a lot too, this isn't a major inconvenience as I'm swapping pads back and forth frequently too....

Sometimes, I revisit my philosophies...

So I got the NASA e-mail about how Raybestos now has a racing line site. They have their "R-Line" which is just OEM quality, their Speciality line for "police cruisers" and other "high performance" applications..

In the past, I've bought these rotors, and quite honestly, haven't noticed any major trend in anything. I found thatthe cheapest rotors are cheap to replace, and last marginally less time if any. I had one rotor crack on a first track session (probably just bad metallurgy from the factory) and since moved my RockAuto orders over to the Wagner line, and thus get a front rotor for around $40, and these seem to bend less.

I can't say I've been a big fan of any Raybestos products. I want to say Wagner is the best on a factory brake set up that I've used, but there again... that's just based on what I've used.

I know the "correct answer" is to put a $2500 big brake kit on my $10,000 car that's only aging out and is just a simple little V6 auto anyway, right?

But if dumb me insists on running cheap rotors, am I doing this right? Does anyone have a particular brand they really had good luck with that might be worth say, jumping from $40 to $70 each?



Too Long, Didn't Read (TL;DR), I currently buy $40 rotors and don't intend to jump to a $250 rotor on a $2500 kit. Is it worth it to buy a $80 rotor of "higher quality" for the brake system I havE?
 
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I would also suggest the StopTech slotted rotors. They are essentially high carbon Centric Premium rotors with slots.

And they are also available Cryo treated for about $25 more at TireRack.

I think they are about $100-110 non-Cryo treated and $125-135 Cryo treated.

I have had excellent results and life with my non-Cryo rotors but next time I replace my rotors I will pay the little bit extra for the Cryo rotors.
 

Duane Black

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I ordered a set since I seem to crack those more often than fronts anyway

Then I would recommend you upgrade your rear rotors to the 13.8" 2013-2014 GT500 rotors. You still use your current calipers and pads but you'll need an adapter available from ncmustangparts on eBay.

If you plan on upgrading your rear gears or differential, or otherwise pulling your axle, then buy the OEM axle brackets for the GT500. Full Tilt Boogie makes aluminum versions of these.

The added diameter not only increases heat dissipation, it also provides more brake torque. This can help with brake dive and overall brake performance.

Added aesthetic benefit of filling up that empty space in the wheel.

When you want to buy such rotors on-line, you'll have to pretend you have a 13-14 GT500 for them to show up in the listing.
 

Fair

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BTW Terry Fair of Vorshlag @Fair used Centric Premium rotors on his S197 project cars.

His development thread contains multiple references to them. This is just one:
https://www.vorshlag.com/forums/for...011-mustang-gt-s197-development-thread/page24

Centric 14 Premium Rotor S197 Mustang

Yes, the Centric Premium line of rotors is pretty good and we beat the snot outta those things on our S197 Mustang. Centric was purchased by StopTech years ago so sometimes they come in StopTech boxes - but its the same rotor, no slots or holes or any tricks. They make slotted and cryo treated versions of course, but there's no magic there. Slots only wear pads more quickly. The econo line from Centric doesn't have the black powder coated centers (see above), so they get rusty looking pretty quickly, otherwise it is the same casting. We have used some cheaper brand rotors and had worse longevity, so we stick with Centric as the baseline.

DSC_6938-L.jpg

As heavy as these cars are and as quickly as they eat rotors, I have a hard time justifying $800 a pair for 2-piece rotors for use with the stock Brembo calipers. Why spend 10X as much for a few pounds of savings on a 3600 pound car, when they will have virtually the same lifespan. 2-piece rotors by themselves don't wear appreciably longer.

_D4A0117-S.jpgS550 Ford Mustang 15 Brake Kit with Ford Rotors

We have actually switched a number of our OEM based brake upgrade kits for the Mustangs to Ford sourced rotors, for various logistical reasons, and the Ford bits do look prettier. They cost more from Ford but due to shipping costs (and having to ship heavy rotors twice more than doubles their cost) it isn't a whole lot more for us. We have eaten the difference. Our S550 15" 6 piston front kit (above right) is all Ford sourced, as is the S550 rear kit (above left). We're moving the S197 kits to Ford sourced rotors next.

Drift%20Smoke%20-6-X2-S.jpg_DSC1754-S.jpg

WARNING: I used to think that the stock S197 Brembo front brake package was more than enough, but I want to caution everyone that thinks the OEM versions are always "all you need" for track use. The 14" rotor / 4 piston Brembo has it's limits, as I found out the hard way. With ducted brake cooling and decent pads (but several stupid mistakes that I own - including too thin pad material, the wrong fluid, and only 3" brake hoses) I ran out of brakes at 150 mph at Road Atlanta in 2014 and had a nasty crash. It fractured a vertebrae that left me in a lot of pain for over a year (that one is permanently crushed). So there can be consequences for cheaping out on brakes...

_DSC6319-S.jpg_DSC4425-S.jpg

I have learned a lot of lessons that I have tried to share from this incident. I am vigilant about checking pads (and keeping spares in the trailer) and rotors, running the right fluid (we now run Motul 660 vs 600 when the caliper temp strips are registering 500+ degrees!), and we have added 4" brake cooling options for this chassis for those that need it (and have our brake cooling deflector version coming for this chassis later this month). For the S550 we only sell a 4" ducted brake backing plate option - never made a 3" kit for these cars (well and our deflector kit). Brake cooling is very important! We noted immediate improvements in longevity and caliper temp data with the bigger cooling option.

DSCN1334-S.jpgDSCN1832-S.jpg

The base 14" diameter, inverted hat, 4 piston front brakes on the S550 are a sad, dangerous joke - a faster driver can fade these in LESS THAN ONE LAP, and in 8 laps I took full depth stock pads down to the backing plates. Of course the 15" 6 piston Brembo setup works very well and with good pads, fluid, and 4" brake cooling we had excellent luck - even using the cheapest Centric econo rotors.

B61G4028-S.jpgP7A_1298-S.jpg

But as good as the 15" 6 piston brakes were, moving to a 2-piece 380x34mm rotor and 6 piston motorsports caliper was another step beyond. This is a costly upgrade we don't push on newbies or casual HPDE folks, but this level of brake DOES make a difference. And the consumables DO last longer (we have seen a 2x improvement in pad wear and 3x in rotor ring life.) This upgrade allowed my 3800 pound S550 pass cars under braking that weighed half as much. Of course the Ford ABS programming is a part of the baking advantage, but we logged higher peak (1.5g) and sustained braking g-forces on these brakes vs the best 15" OEM brake parts. So spending on brakes when you go to a proper caliper/rotor/pad combo can have real benefits.

IMG_1472-S.jpgIMG_1770-S.jpg

General brake system adivce: no matter your budget or "class" of braking system: 1) do not ignore data - use the caliper temp strips and rotor paint to see if the pad, rotor and fluid within safe limits! This is what bit me in 2014 and I won't ever make that mistake again. 2) Keep spare brake pads on hand in case you run out of pad thickness at an event. Thin pads do not insulate the fluid from rotor heat as well as thicker pads will. Don't just say "I'm gonna send it!" like an idiot when your pads are at 3mm thickness or less - another thing that bit me! 3) Run proper brake cooling, and if you have brake duct hoses keep them in good condition. On a wide tire setup that means replacing hoses once or twice a season. Routing the hoses so that they are never near the tire usually adds lots of bends that KILLS airflow. More airflow is always better for rotor, pad, and hub life - not to mention a good "pedal" through your track session! 4) Higher boiling point brake fluid NEEDS TO BE REPLACED MORE OFTEN, not less often. It is not magic - if you use Motrul 660, Castrol SRF or the other higher temp fluids they need to be flushed on a shorter interval than the lower cost fluids. It has to do with their compatibility with water / absorption, and it is a trade off of long fluid life vs boiling point.

_DSC1759-S.jpgDSC_4908-S.jpg

I hope that didn't stray too far off topic, but somebody tagged me in and I wanted to keep the fact that we used "cheap rotors" in perspective. If I had to go back and do 2014 over again I would have INVESTED in proper motorsports brakes after reading the warnings the data from the calipers and pad wear gave me. I ignored that data and paid the price with a broken back. SPEND MONEY WHERE IT MAKES SENSE - brakes are never a place to pinch pennies.

Cheers,
 

Fair

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Is the Centric premium line the 120.xxxxx, the 121.xxxxx, or 125.xxxxx?
CENTRIC 121.xx is the "C-TEK" econo-line uncoated plain rotor
CENTRIC 120.xx is the Premium series which have black coated centers
CENTRIC 125.xx is the "High Carbon" Plain rotor that we never use
CENTRIC 320.xx is some new "GCX" Elemental Protection coated series I have never heard of until today ;)
 

Duane Black

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So if I don't mind surface rust, I just stick to 121? In your article you said it's the same casting, yet you're using the 120 series. Is there better metallurgy there too, in your opinion?
 
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Terry @Fair ,

I understand the slotted ones wear the pads faster but I actually prefer them on the street (I swap between compatible street & track pads) since they seem to increase braking when the pads are cold. Irrespective of whether they are plain or slotted, wouldn't the cryo treated rotors be better?

Were you using titanium shims during that 2014 incident? Any thoughts on the shims?
 
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I am interested in why the high carbon content rotor is not used as well. I started using Autozone Duralast Gold on my rear brakes and they have outlasted anything I have tried before, and they too are a high carbon content rotor. No slots or holes, just a really tough brake rotor. I use Girodisc two piece on the front S197 4 pot Brembo, 4" ducts on a 3500lb car with driver.
 
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Higher boiling point brake fluid NEEDS TO BE REPLACED MORE OFTEN, not less often. It is not magic - if you use Motrul 660, Castrol SRF or the other higher temp fluids they need to be flushed on a shorter interval than the lower cost fluids. It has to do with their compatibility with water / absorption, and it is a trade off of long fluid life vs boiling point.

Terry, I agree that flushing fluid more often to keep the fluid closer to it's dry boiling point results in the best performance. However I disagree that it has to be done even more often than when using RBF600, at least when it pertains to the Castrol SRF.

The RBF660 has the same wet boiling point as RBF600 then assuming each would degrade (water absorption) to their wet boiling point (401°) over the same period of time, then the 660 would have a higher degradation rate since it is starting from 617° vs RBF600's 594°. They each drop about 200° from high to low boiling points.

Castrol SRF on the other hand goes from a high of, depending on source data, either 594° or 608°

This is only a drop of about 100° from high to low.

Theoretically, over the time period that either 660 or 600 get to about a 500° wet boiling point, the SRF would only drop to 550° and provide superior performance to RBF660.

Do you have any info or experience that SRF's water absorption rate is any faster than that of the RBF660?
In any case, it would appear that SRF would never degrade to the level of RBF660.

Therefore I would expect that the SRF would only need to be replaced as often as RBF660 but not more often. On less demanding tracks it would seem it could be flushed less frequently. Of course, bleeding should still be done frequently regardless of fluid type.
 

Norm Peterson

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Terry, I agree that flushing fluid more often to keep the fluid closer to it's dry boiling point results in the best performance. However I disagree that it has to be done even more often than when using RBF600, at least when it pertains to the Castrol SRF.

The RBF660 has the same wet boiling point as RBF600 then assuming each would degrade (water absorption) to their wet boiling point (401°) over the same period of time, then the 660 would have a higher degradation rate since it is starting from 617° vs RBF600's 594°. They each drop about 200° from high to low boiling points.
I think we'd need specific data from Motul to determine whether 660 needs to be flushed more frequently than 600. However, it's entirely possible that the 660 does absorb moisture more readily as a side effect to the makeup that gives it a higher dry boiling point.


Norm
 
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Good advice, we use AP super 600 it's relatively inexpensive so we don't sweat bleeding it often, also we are Hawk people, but the fact is, you really can't over maintain your brakes, when we go to the races we carry a stack of broken in, matched rotors and pads and over a 5 day race weekend, change them at least once, and bleed pretty much every day at the end of the last session. The ducting is a place where you can get a lot of improvement and cheaply, it pays to make sure the ducting is not kinked or blocked.
 

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