Girodisc rotor to swap to ACR s CCM today

[stradman]

Hi Guys
Just swapped over my CCM's to Girodisc today. Looks great on car. Downside is adding 5kg each wheel front and 3.5kg to the back each corner. So total 17kg or about 37.5 lbs. And the appearance of brake dust! But I really don't think it will make much difference to track duties on this car once everything is rolling and with 600ft/lbs of torque, I'm sure engine won't blink.
Good news however is that on my track work(which is basically the only thing the car does, I won't worry so much about pads and modulation is also better than CCM.

[Arizona Vipers]

40 lbs of unsprung weight is a lot of lost performance IMO, but congrats for making the car the way you want it!
I have almost 4000 track miles on my ACR and have never replaced rotors and I'm on my 3rd set of front pads, still on original rear pads.
If you want that weight back switch to Pirelli slicks, they will be 55 lbs lighter than the Kumho's, 40 lbs lighter than Hoosiers. ;)

[GTSilver]

Hi Guys
Just swapped over my CCM's to Girodisc today. Looks great on car. Downside is adding 5kg each wheel front and 3.5kg to the back each corner. So total 17kg or about 37.5 lbs. And the appearance of brake dust! But I really don't think it will make much difference to track duties on this car once everything is rolling and with 600ft/lbs of torque, I'm sure engine won't blink.
Good news however is that on my track work(which is basically the only thing the car does, I won't worry so much about pads and modulation is also better than CCM.

Congrats and although yes you've added back weight on the car the performance based on what others have tried them is great. I wanted to do the switch as well but I'm out of budget for this year track expenses and will give the CCB another season and will be trying pagid pads rather than OEM to improve bite and modulation. After this season and if they don't perform as well I'll convert to Girodisc and other things for next season.

[Arizona Vipers]

Congrats and although yes you've added back weight on the car the performance based on what others have tried them is great. I wanted to do the switch as well but I'm out of budget for this year track expenses and will give the CCB another season and will be trying pagid pads rather than OEM to improve bite and modulation. After this season and if they don't perform as well I'll convert to Girodisc and other things for next season.

How much are the Pagid pads?

[stradman]

40 lbs of unsprung weight is a lot of lost performance IMO, but congrats for making the car the way you want it!
I have almost 4000 track miles on my ACR and have never replaced rotors and I'm on my 3rd set of front pads, still on original rear pads.
If you want that weight back switch to Pirelli slicks, they will be 55 lbs lighter than the Kumho's, 40 lbs lighter than Hoosiers. ;)

Well Arizona congrats on being only on 3rd set of pads. I don't know how you do it. I've got about the same track miles and pads were starting to become an issue with increasing frequency with surface of front rotors(back are ok still) becoming increasingly like a cheese grater. Are you using stock pads?
Also interesting article on light vs heavy brakes. I agree with that article which suggests that something the Viper with its torque, won't practically be affected.

https://www.dba.com.au/brake-discs-is-lighter-better-2/

Also I believe that its the outer edge of the wheels/tires rather than near the (wheel) center that is more important for weight. And as a result, the rotating weight of rotors is closer to the wheel hub and not as important as the wheels and tires. Not saying there is zero effect just saying not as important. You just have to offset the pros and cons of CCM in that matter.

Spending money on weight reduction in the wheels and tires(where possible), and thereby reducing weight out a little further away from the center, where it does the most good, we would do much better.

[38D]

The benefit of lower unsprung weight is more in the suspension VS accel/decel. The lower weight allows spring to move more quickly, effectively allowing the tire to follow the pavement better. This is way oversimplified, but gives the gist.

Here’s a cool little physics tool that shows this graphically. You can play with the mass to see how the spring changes.
https://www.myphysicslab.com/springs/single-spring-en.html

[Arizona Vipers]

Well Arizona congrats on being only on 3rd set of pads. I don't know how you do it. I've got about the same track miles and pads were starting to become an issue with increasing frequency with surface of front rotors(back are ok still) becoming increasingly like a cheese grater. Are you using stock pads?
Also interesting article on light vs heavy brakes. I agree with that article which suggests that something the Viper with its torque, won't practically be affected.

https://www.dba.com.au/brake-discs-is-lighter-better-2/

Also I believe that its the outer edge of the wheels/tires rather than near the (wheel) center that is more important for weight. And as a result, the rotating weight of rotors is closer to the wheel hub and not as important as the wheels and tires. Not saying there is zero effect just saying not as important. You just have to offset the pros and cons of CCM in that matter.

Spending money on weight reduction in the wheels and tires(where possible), and thereby reducing weight out a little further away from the center, where it does the most good, we would do much better.

How many front pads have you used in how many track miles? Also, I ditched the sensors they are worthless, you should just go by physical measurement of the pad itself. Once the sensors told me to change the pads, they weren't even 70% worn.
That article is talking about iron brakes. Obviously CCB's dissipate heat better than iron or they wouldn't even exist. Iron for Iron yeah the more mass the more heat it can dissipate. The CCB's being lighter doesn't mean they can't dissipate as much heat as a heavier iron rotor. It's why the GT2RS has standard CCB's versus them being optional on most other 911 models. That being said, my factory stop tech brakes I never found their limit, I went with the ccb's to reduce unsprung mass on the car. 10 lbs a wheel doesn't sound like a lot, but that's a lot of weight pounding up and down on your dampers

[Bruce H.]

Some PCA instructors and club racers I track with are swapping out the CCB's on GT3 and RS's for iron, swapping the 20" wheels for smaller, and ditching the MPSC2's. Not unusual to diverge from manufacturer's spec that are naturally biased towards sales verses heavy track use.

[Arizona Vipers]

Some PCA instructors and club racers I track with are swapping out the CCB's on GT3 and RS's for iron, swapping the 20" wheels for smaller, and ditching the MPSC2's. Not unusual to diverge from manufacturer's spec that are naturally biased towards sales verses heavy track use.

There's a few guys on here that have switched to the Girodisc's and like them. If it's going to save you a lot of money over time, for some that's worth adding a bunch of unsprung mass. If you poke around online you can find these pads and rotors for MUCH MUCH cheaper than you think.

[Bruce H.]

Very glad to have you and others sharing your knowledge and experiences!

[Racingswh]

I like the Girodisc's. They work really well for me, longer pad life and the added weight hasn't slowed me down.

[stradman]

How many front pads have you used in how many track miles? Also, I ditched the sensors they are worthless, you should just go by physical measurement of the pad itself. Once the sensors told me to change the pads, they weren't even 70% worn.
That article is talking about iron brakes. Obviously CCB's dissipate heat better than iron or they wouldn't even exist. Iron for Iron yeah the more mass the more heat it can dissipate. The CCB's being lighter doesn't mean they can't dissipate as much heat as a heavier iron rotor. It's why the GT2RS has standard CCB's versus them being optional on most other 911 models. That being said, my factory stop tech brakes I never found their limit, I went with the ccb's to reduce unsprung mass on the car. 10 lbs a wheel doesn't sound like a lot, but that's a lot of weight pounding up and down on your dampers

I've changed about 3 sets of pads in same miles as you however the frequency is getting more frequent. I have also ditched the sensors but you do need to get wheel off to look at inside pad as well as you can sometimes have uneven wear. The thing is I've had the ACR for about a year now but started tracking it regularly about 7 months ago. The first 3 months I was learning the car and not really pushing it. However I defo am getting quicker in the last 2-3 months and hence pad wear is increasing as well, and I'm not near the limit of the car yet. So I see where this is going and CCB's for me are just not practical. I know the Girodiscs won't slow me down. In fact I think I will be faster as bite and modulation is better and so will be able to dive into corners with later braking and more confidence. Of course everyone is different and so you adapt according to what works for you. And here is the thing. You say you want to reduce unsprung weight. Yes but ultimately for what purpose? I have to presume it is for going round a track quicker isn't it? Well if you won't be going any slower with a disc that gives you more confidence and better bite and better pad life surely then that should be your choice for such purposes, no?

Sure I know the new 2RS/3RS's etc have carbons as do Macca's but many track guys I know remove them and go to steel. Doesn't make em any slower I can tell you! But manufacturers need to be seen as using the latest tech because that is what customers pay for and expect I guess particularly if the competition has it...And anyway remember these cars are by and large primarily driven on the road by the vast proportion of owners. So for that purpose and say for only the occasional track day then CCM/CCB's are cool and useful and will last ages. However for pure track cars where there is far more punishment you will see their limitations and thus, I can't see the point.

[FSTENUF]

30477
30478
Best swap out for the $$$

[Arizona Vipers]

Are you guys selling your factory rotors? PM me if you are.

[1ststrike]

Noticed your car lift fstenuf. What kind is it and how do you get the car over it and still line up the lifting points?

[stradman]

Are you guys selling your factory rotors? PM me if you are.

No. I'm keeping them for posterity. They go with car I guess...

[darbgnik]

No. I'm keeping them for posterity. They go with car I guess...

Makes sense. If the next guy isn't a track rat, they'll last the remaining life of the car with no dust(to some that's important :confused: )........

[Arizona Vipers]

I like the Girodisc's. They work really well for me, longer pad life and the added weight hasn't slowed me down.

What do you pay for the pads for the Girodiscs and what were you paying for the OEM pads?

[Darius]

I recently replaced my fronts only to Girodisc. Still running Carbon rears. I've gone through 3 sets of fronts also. The first set lasting the longest, once the rotor pits it chews through pads in 2 track days. Also the brake performance suffered drastically with a pitted rotor.

[Arizona Vipers]

I recently replaced my fronts only to Girodisc. Still running Carbon rears. I've gone through 3 sets of fronts also. The first set lasting the longest, once the rotor pits it chews through pads in 2 track days. Also the brake performance suffered drastically with a pitted rotor.

Were you keeping the holes in the rotors clean? When I met Tom O'dell he said one of the most important things on the ACR was keeping those holes clean. It's a huge pain in the ass to clean them all, but I try to do it before each track weekend and I seem to have had much better luck with the carbon brakes than a lot of you guys.

[ACRucrazy]

Were you keeping the holes in the rotors clean? When I met Tom O'dell he said one of the most important things on the ACR was keeping those holes clean. It's a huge pain in the ass to clean them all, but I try to do it before each track weekend and I seem to have had much better luck with the carbon brakes than a lot of you guys.

How are you doing that? wood dowel? vacuum?

[Arizona Vipers]

How are you doing that? wood dowel? vacuum?

Yeah a wood dowel. Vacuum wont do anything, the holes basically fill hard solid you have to punch through them. It takes about 30 minutes to do all four. I forget the exact explanation from Tom, but he made it seemed extremely important, and nobody on this planet would know better than him.
I just make it a habit of doing it when I bleed the brakes on my lift.

[stradman]

I was using a Jet washer spray. Did the job wonderfully in a fraction of the time...However Girodiscs...No holes! Yaay!

[Racingswh]

What do you pay for the pads for the Girodiscs and what were you paying for the OEM pads?

I can't remember the pads alone cost for the Raybestos pads. The whole deal was around 3700 as I recall.

My brake spend for pads and rotors had I stayed with the CC brakes was tracking at north of 20k annually which consists of 10 or so two to three day events per year.

For me I have found that because I drive the car far below it's ultimate limits less weight isn't critically important to me yet. I have many seconds of lap time to find as a driver not tenths which is where reducing unsprung weight would help.

[The Frenchy]

interesting i will wait your feedback on this Girodisc :)

[ACR Steve]

Racingswh- "For me I have found that because I drive the car far below it's ultimate limits less weight isn't critically important to me yet. I have many seconds of lap time to find as a driver not tenths which is where reducing unsprung weight would help. "

Come to our Lime Rock event this year we will find you those seconds I guarantee :)

[Racingswh]

Racingswh- "For me I have found that because I drive the car far below it's ultimate limits less weight isn't critically important to me yet. I have many seconds of lap time to find as a driver not tenths which is where reducing unsprung weight would help. "

Come to our Lime Rock event this year we will find you those seconds I guarantee :)

Thanks for that invite Steve and I will take you up on that! Not only do I want to come up and get your invaluable feedback regarding where I can improve as a Driver but also to see if you can get your ACR into the air as high as you do your Porsche?? :)

[Camfab]

This is a really interesting thread. For so many years all we heard was that Dodge was behind in braking because it did not offer a CCB braking package. What's interesting to me, is that there seems to be a price point that's ultimately driving the change back to the iron rotor. Clearly in the racing world every once counts and with massive budgets the justification for exotic materials is a no brainer for the win. I would love to see real world data using an accomplished driver, say Darius for example, going back to back, same track, same day with no other changes other than iron disc to CCB and equivalent pads. Using the same exact test parameters with an average driver and comparing them to the other test. Thanks for sharing.......

[ACR Steve]

:) we just booked it our track day - Save the date

https://driveviper.com/forums/threads/20648-NY-CT-Lime-Rock-Viper-NASA-Big-Track-day-July-13-14

[mike@girodisc]

This is a really interesting thread. For so many years all we heard was that Dodge was behind in braking because it did not offer a CCB braking package. What's interesting to me, is that there seems to be a price point that's ultimately driving the change back to the iron rotor. Clearly in the racing world every once counts and with massive budgets the justification for exotic materials is a no brainer for the win. I would love to see real world data using an accomplished driver, say Darius for example, going back to back, same track, same day with no other changes other than iron disc to CCB and equivalent pads. Using the same exact test parameters with an average driver and comparing them to the other test. Thanks for sharing.......

We have a customer with 4 identical Ferrari 458 Challenge cars that have all been converted to our iron rotors with Raybestos ST43 pads and when they first put everything on one of the cars about two years ago I was at the track with them and they had both Anthony Lazzaro and Jeff Westphal (the 2nd non-German to ever take the pole at the 24 hours of Nurburgring) there as driver coaches. Turning 1 min. 13 sec. laps both drivers averaged about 1 sec. a lap faster on the heavier iron set up. They both said that key was the consistency of the iron set up along with a little added bite from the brake pads allowed them both to go much deeper into the braking zones. Confidence is everything when it comes to brakes, when you as a driver consistently know exactly how your brakes are going to work at every braking zone you can actually push them to the ragged edge. Carbon ceramic rotors simply do not have enough thermal capacity to provide the same consistency as an iron set up.

Also of note on these Ferrari's the increase in weight is about 45 lbs., both drivers stated that it is completely inconsequential and much prefer the iron package.

Most people always talk about cost being the driving force in swapping out the CCM's and I don't discredit that but in this case they swap because they're just flat out faster on this set up.

First picture shows their new 488 which we recently converted and the second is our kit with the ST43's on one of the 458's.

3054230543

[Racingswh]

Also of note on these Ferrari's the increase in weight is about 45 lbs., both drivers stated that it is completely inconsequential and much prefer the iron package.

Most people always talk about cost being the driving force in swapping out the CCM's and I don't discredit that but in this case they swap because they're just flat out faster on this set up.

I am not surprised at all. Most people just look at me odd when I tell them how I am not a fan of the CC brakes and they do nothing to improve the performance of the car. Great information Mike!! Thanks!!

[esm_viper]

Hey Mike! Nice to see you posting here. I'm still going to buy those TA sized rotors from you soon. Thanks for all you help!

[stradman]

To my mind at least its simple. As i mentioned earlier, if a car is used primarily on the street and only the occasional track day(probably 98% of ACR's) then there is no question in my mind, the CCM are the go to set up. No brake dust, rotors will likely last a very long time, lighter(not that you are likely to detect this in anyway in those circumstances though). However if your car is a regular track slag(like mine) then there are limitations to the CCM's so you probably need to swap to iron set up...

[ForTehNguyen]

CCB are fragile if you are doing service around them, its highly recommended you use those rotor protectors. Chipping the rotor by dinging it with a tool or putting on the wheel wrong is an expensive mistake. Just buy some cheap pipe insulation as a protector

[Werks]

CCB are fragile if you are doing service around them, its highly recommended you use those rotor protectors. Chipping the rotor by dinging it with a tool or putting on the wheel wrong is an expensive mistake. Just buy some cheap pipe insulation as a protector

That's one of the old wives tails about CCM's told by people that frankly have no experience using them. I've been tracking with them since 2011 on my Vette and bumped wheels into them, banged into them taking calipers off etc. etc. and have never, ever used a rotor protector and have also never, ever chipped a rotor (and that's having gone through at least 4 sets of CCM rotors on track). The biggest issue with CCM other than cost and accelerated pad wear once the rotors start to pit due to high temps is lack of feel which Mike@Girodisk touches on in his post. Simply put there is a significant lack of available brake pad compounds that can resist the high temperatures developed by CCM rotors, that may and probably will change with time but there certainly has not been the same amount of time and effort put into developing CCM pads as there have been into developing iron rotor racing pads something like the last 60-70+ years! So give time things will no doubt improve but right now brake feel is just not there and most people report that CCM's give a digitial almost on or off brake effect with little ability to modulate brake force (when running at racing speeds). That is the big issue and is also why I'm personally also switching over to iron my self after having tested just about every pad comound available with CCM' and having helped companies test & develop CCM brake pads in the past.

[Racingswh]

why I'm personally also switching over to iron my self

What system are you going to use or will you just change out the rotors?

I had never found CC rotors to be fragile either and have clanked into them pretty good repeatedly. Guess it depends on how you hit them?

[Werks]

What system are you going to use or will you just change out the rotors?

I had never found CC rotors to be fragile either and have clanked into them pretty good repeatedly. Guess it depends on how you hit them?

Over the years I think the only thing that I have not hit them with was a hammer lol but who knows!

As far as the swap to iron I was considering just switching over to CCM replacement iron rotors but until just recently only one company made them to fit my C6Z and being candid I do not trust the products they put out for track use (to be clear I'm not talking about Girodisc). Plus doing that does not address a few things, namely the relative lack of available pad compounds in the pad shape to fit our calipers nor the high price of those available because of the masive pad size used in them due to the high thermal requirements of the CCM rotors they are intended to be used with. In addition you are still stuck with relatively expensive pads and on top of that they are also thin 16mm pads, fine for the street but for track use they are going to wear out and need to be replaced frequently.

So then I looked at some of the track oriented replacement kits (caloiper + iron rotors) from StopTech, AP, Brembo, Wilwood etc but just decided that if I'm going to spend the money I might as well spend it once and be done with it. So I'm now in the process of peicing together a system using racing parts. For the front I picked up a set of AP Racing CP6160 calipers (same as on used on the C7R and a lot of GT2/GT3 cars). One of these calipers only weighs 5lbs, 1/2 of the weight of the 6 piston Brembo CCM caliper and uses 30mm thick pads available in a ton of different compounds and pad pricing generally runs in the $350-$450 range (lower to about the same as what 16mm pads to fit the front CCM caliper cost). For the rear I'm using CP6480 4 piston calipers. Again about a 50% weight reduction in caliper versus OEM and those use 25mm thick pads that run in the $150-$300 range (depending on compound). Next I need to figure out mounting brackets for the calipers and source rotors, so it's a bit more involved than just ordering a bolt on solution but once done it's pretty unlikely that I'll ever be wanting for better brakes lol.

[Camfab]

Great info. guys, thanks for your replies.

[ek1]

Well Arizona congrats on being only on 3rd set of pads. I don't know how you do it. I've got about the same track miles and pads were starting to become an issue with increasing frequency with surface of front rotors(back are ok still) becoming increasingly like a cheese grater. Are you using stock pads?
Also interesting article on light vs heavy brakes. I agree with that article which suggests that something the Viper with its torque, won't practically be affected.

https://www.dba.com.au/brake-discs-is-lighter-better-2/

Also I believe that its the outer edge of the wheels/tires rather than near the (wheel) center that is more important for weight. And as a result, the rotating weight of rotors is closer to the wheel hub and not as important as the wheels and tires. Not saying there is zero effect just saying not as important. You just have to offset the pros and cons of CCM in that matter.

Spending money on weight reduction in the wheels and tires(where possible), and thereby reducing weight out a little further away from the center, where it does the most good, we would do much better.

My front rotors are just about done (1mm left till replacement) and I have about 3,000 track miles on them. I am on my 3rd set of front pads, 2nd set of rear pads. Have not changed the rear rotors yet.

Everyone needs to make sure they run brake ducts since they lower the rotor temp, this slowing down the "cheese grater" effect caused by rotor material burning off.

[Werks]

My front rotors are just about done (1mm left till replacement) and I have about 3,000 track miles on them. I am on my 3rd set of front pads, 2nd set of rear pads. Have not changed the rear rotors yet.

Everyone needs to make sure they run brake ducts since they lower the rotor temp, this slowing down the "cheese grater" effect caused by rotor material burning off.

Sounds about right. Historically over the last 6-7 years of doing track days with my C6Z (with big brake ducts) my front rotors have lasted between 4-5 front pad changes before needing to be replaced.

[CarbonDan]

Resurrecting this thread. How have things been holding up for everyone?

What kind of replacement interval are we seeing with the girodisc rotors and st43 pads?

[blackbeast99]

Resurrecting this thread. How have things been holding up for everyone?

What kind of replacement interval are we seeing with the girodisc rotors and st43 pads?

4 events on mine so far (two day weekends each time 5-10 min sessions). Still have the same pads and rotors (ST47 front, ST43 rear). Stock lines, Motul RBF 600.

[jwalk]

Ok. I put them on in june of 2018. I have done atleast 16 roadcourse days with 5-6 20 minutes sessions. And not that it is that hard on brakes but atleast a dozen autocrosses. Rotors still decent but will probably put fresh rings on over the winter. Only used 2 sets of pads. Probably didnt need to replace the rears but wanted fresh pads all around. Running 43's front and rear. I run Castrol SRF. Love the set up. Great feel. Can run hard with confidence.

[JonB ~ PartsRack]

ok. I put them on in june of 2018. I have done atleast 16 roadcourse days with 5-6 20 minutes sessions. And not that it is that hard on brakes but atleast a dozen autocrosses. Rotors still decent but will probably put fresh rings on over the winter. Only used 2 sets of pads. Probably didnt need to replace the rears but wanted fresh pads all around. Running 43's front and rear. I run castrol srf. Love the set up. Great feel. Can run hard with confidence.


great feedback, thanks...............

[sssammm]

What is the replacement cost?

[jwalk]

What is the replacement cost?

Front rotors-$700 Pads -$400 Rear Rotors-$650 Rear Pads $269 That was 2018. They may have gone up a little since then.

[CarbonDan]

Front rotors-$700 Pads -$400 Rear Rotors-$650 Rear Pads $269 That was 2018. They may have gone up a little since then.

That's really fantastic. Brings the consumable cost way down to track an ACR.

[blackbeast99]

That's really fantastic. Brings the consumable cost way down to track an ACR.
Many vendors/clubs offer discounts too for/up to about 10% from what I've seen as well...love my Girodisc setup.