Racing Brake 2PC rotors 10lbs lighter than Z51!
01-17-2014, 09:08 PM
#1
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St. Jude Donor '14
Racing Brake 2PC rotors 10lbs lighter than Z51!
I have these 2pc light weight rotors on my CTS V and I'm pleased to announce that Racing Brake will be making these for the Stingray and Stingray Z51 models as well! Weapon X Motorsports will be the exclusive vendor for these rotors for the next few months as we work through this with them! They're also working on forged calipers 6f/4r for a complete system! We're looking for a C7 in the Orange County/LA area to complete the development on those as well, so if you're out that way, send me a PM and I'll get you connected!
They're a very quality 2 piece brake rotor, have true replacement rings, and saved about 10lbs of rotating mass over the standard C7 Z51 brakes.
The stock rotor weights are in!
Front two piece:
Dimension: OE=345x30mm
Weight: OE=20 lbs
Rear two piece:
Dimension: OE=340x26mm
Weight: OE=18 lbs
________________________________________ ________________________________________ _________
Racing Brake rotors are in design now, but expected results for you track guys already look good!
Front two piece:
Dimension: RB=340x31mm (1mm thicker)
Weight: RB=16.5 lbs (projected)
Rear two piece:
Dimension: RB=340x26mm
Weight: RB=16.5 lbs (projected)
Total rotational weight savings are nearly 10lbs projected! That is a lot of weight for already light weight rotors when you take into account inertia and rotational mass!
They're a very quality 2 piece brake rotor, have true replacement rings, and saved about 10lbs of rotating mass over the standard C7 Z51 brakes.
The stock rotor weights are in!
Front two piece:
Dimension: OE=345x30mm
Weight: OE=20 lbs
Rear two piece:
Dimension: OE=340x26mm
Weight: OE=18 lbs
________________________________________ ________________________________________ _________
Racing Brake rotors are in design now, but expected results for you track guys already look good!
Front two piece:
Dimension: RB=340x31mm (1mm thicker)
Weight: RB=16.5 lbs (projected)
Rear two piece:
Dimension: RB=340x26mm
Weight: RB=16.5 lbs (projected)
Total rotational weight savings are nearly 10lbs projected! That is a lot of weight for already light weight rotors when you take into account inertia and rotational mass!
01-18-2014, 01:39 PM
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St. Jude Donor '14
Yes, they are! RB's patented center mount design uses the same disc for either left or right by flipping the hat. A serial of BBK w/ RB calipers are being finalized upon spindles receipt.
The fronts:
390mmx34 19" wheels needed
380mmx34 19"
350mmx32 18"
The fronts:
365mm 20" wheels needed
340mm 19"
The fronts:
390mmx34 19" wheels needed
380mmx34 19"
350mmx32 18"
The fronts:
365mm 20" wheels needed
340mm 19"
01-20-2014, 04:45 PM
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St. Jude Donor '14
Pricing hasn't been firmed up yet, but I will be doing a big intro group buy. Working on full brake kits right now too, comparable to the size that's on the Z06!!!
01-20-2014, 06:02 PM
#7
Rotational inertia of a brake disc is not very important relative to that of the tire followed by the wheel. Rotational inertia is a function of the mass and the radius squared. Most of the tire's mass is at the outside, so radius = 13 and r^2 = 169 and mass is 27 lbs, so a factor of 4560, and most of the wheel's weight is at its outside with a radius of 9.5 and r^2 = 90 with a weight of 25 lbs, so a factor of 2250, so squaring the radius of each and adding the wheel and tire's rotational inertia quite dominates the effect of a brake lighter by a couple of pounds, whose equivalent radius is about 7.7 and r^2 = 59 with a mass of 20 lbs, so a factor of 1180 out of a total of 7990. If you drop the weight of the rotor by 3 lbs, the rotor's contribution factor drops to 1000, dropping the total to 7800, or 2% drop in rotational inertia. Drop is slightly more if you consider the part of the tire weight is the sidewall, and part of the wheel weight is the spokes, but still not a big effect.
If you want to drop the rotational inertia, start by going to a lighter tire, as that will have much more effect, followed by a lighter wheel.
The unsprung mass benefit is there however, but taking 2-3 lbs off the total of tire plus wheel plus suspension and caliper etc. is not going to have a big effect in terms of % unsprung weight. Tire + wheel + 20 lb rotor = 72 lbs, so dropping 3 lbs off that is not so much.
It is not like there is no benefit, but it is not that big.
If you want to drop the rotational inertia, start by going to a lighter tire, as that will have much more effect, followed by a lighter wheel.
The unsprung mass benefit is there however, but taking 2-3 lbs off the total of tire plus wheel plus suspension and caliper etc. is not going to have a big effect in terms of % unsprung weight. Tire + wheel + 20 lb rotor = 72 lbs, so dropping 3 lbs off that is not so much.
It is not like there is no benefit, but it is not that big.
01-22-2014, 11:13 AM
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St. Jude Donor '14
Appreciate the contribution; however, no one stated rims or tires were less important for weight reduction with respect to rotational inertia. Furthermore, by your weight reduction logic, the outgoing ZR1 and incoming Z06 shouldn't bother offering ceramic options for reduced weight and superior heat transfer properties.
Dropping an additional 14% of an already light weight brake rotor weight (while getting a better rotor) IS a big deal for any performance enthusiast as well as the GM engineering team. The bean counters found the added performance gain and 18% weight reduction of the Z51 optioned SR rotors out weighed the additional cost as a factory option.
As far as performance, most two piece rotor hats are made of aluminum alloy and the discs are made of either cast iron or ceramic alloys. Aluminum is better for heat dissipation which is important for rotor wear and brake fade; however, the iron was most likely chosen due to cost on a mass production performance vehicle. Ductile iron is stronger than cast iron at least. The SR rotors are considered a 2pc rotor but like other GM 2pc rotors offered OEM, but don't offer replaceable rings. Additionally, you have to mess around with the cooling rings as well if you track the car and want the most benefit which is another PITA.
Manufacturer data:
RB Rotor Material
Alloyed iron formula adds strength and heat resistance. Heat treating further improves rotor performance for a more uniform and stabilized microstructure.
Design:
1. The cooling vanes are of a convergent nozzle design, which increases airflow and turbulence and makes discs cooler. (Illustration #1)
2. The center-mount flanges for hat mounting to the rotor ring have several benefits. (Illustration #2)
It allows the ring to be used on either side of the vehicle simply by mounting the hat on either side of the ring (unidirectional).
The stress load transferred from the ring to the hat is balanced.
Air inlets are widely open to both inboard and outboard sides of the rotor. More air suctions and even temperature on both sides of the disc surface.
Heat transfer from the disc surfaces to the hat is even and minimized by increasing the flange length and the airflow around the flanges.
Mounting flanges are on both friction surfaces ultimately provides excellent heat balance.
3. Exclusive full floating design with 10.9 grade alloyed hardware. Hardware is DACRO coated and crimp locking. DACRO is highly corrosion resistant and provides a film for easier movement between the hat and rotor ring as disc expands and contracts and the crimp design provides positive engagement without rattling or torque loss at temperature.
Dropping an additional 14% of an already light weight brake rotor weight (while getting a better rotor) IS a big deal for any performance enthusiast as well as the GM engineering team. The bean counters found the added performance gain and 18% weight reduction of the Z51 optioned SR rotors out weighed the additional cost as a factory option.
As far as performance, most two piece rotor hats are made of aluminum alloy and the discs are made of either cast iron or ceramic alloys. Aluminum is better for heat dissipation which is important for rotor wear and brake fade; however, the iron was most likely chosen due to cost on a mass production performance vehicle. Ductile iron is stronger than cast iron at least. The SR rotors are considered a 2pc rotor but like other GM 2pc rotors offered OEM, but don't offer replaceable rings. Additionally, you have to mess around with the cooling rings as well if you track the car and want the most benefit which is another PITA.
Manufacturer data:
RB Rotor Material
Alloyed iron formula adds strength and heat resistance. Heat treating further improves rotor performance for a more uniform and stabilized microstructure.
Design:
1. The cooling vanes are of a convergent nozzle design, which increases airflow and turbulence and makes discs cooler. (Illustration #1)
2. The center-mount flanges for hat mounting to the rotor ring have several benefits. (Illustration #2)
It allows the ring to be used on either side of the vehicle simply by mounting the hat on either side of the ring (unidirectional).
The stress load transferred from the ring to the hat is balanced.
Air inlets are widely open to both inboard and outboard sides of the rotor. More air suctions and even temperature on both sides of the disc surface.
Heat transfer from the disc surfaces to the hat is even and minimized by increasing the flange length and the airflow around the flanges.
Mounting flanges are on both friction surfaces ultimately provides excellent heat balance.
3. Exclusive full floating design with 10.9 grade alloyed hardware. Hardware is DACRO coated and crimp locking. DACRO is highly corrosion resistant and provides a film for easier movement between the hat and rotor ring as disc expands and contracts and the crimp design provides positive engagement without rattling or torque loss at temperature.
Last edited by Ben@WeaponX; 01-22-2014 at 11:31 AM.
01-25-2014, 12:18 PM
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St. Jude Donor '14
I'll be doing a 5 man group buy next week on these! $1399 shipped for all four rotors. I'm getting the first set, so 4 more guys interested?
1. Ben
2.
3.
4.
5.
1. Ben
2.
3.
4.
5.
01-25-2014, 01:46 PM
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St. Jude Donor '14
I'm not sure what you mean where does the steel come from. Also not sure if you were using Racing Brake actual rotors or not but I've never seen any failures. I have a dozen clients using these on 4400lb CTS Vs racing on all sorts of road course events including the Cadillac Challenge series on the west coast without any issues whatsoever.
02-18-2014, 09:44 AM
#13
I'm not sure what you mean where does the steel come from. Also not sure if you were using Racing Brake actual rotors or not but I've never seen any failures. I have a dozen clients using these on 4400lb CTS Vs racing on all sorts of road course events including the Cadillac Challenge series on the west coast without any issues whatsoever.
02-18-2014, 07:04 PM
#14
Good talking with you today Ben, after hearing more about these they certainly seem like a good alternative. If they can stop a CTS V they should be able to stop a Corvette.
It seems Corvette made a cost cutting decision when they used iron for the hats instead of Aluminum. They compare these discs to BMW M floating rotors but M rotors do indeed have Aluminum hats. The Aluminum and veins in these give you a fighting chance of not boiling your brakes.
It seems Corvette made a cost cutting decision when they used iron for the hats instead of Aluminum. They compare these discs to BMW M floating rotors but M rotors do indeed have Aluminum hats. The Aluminum and veins in these give you a fighting chance of not boiling your brakes.
04-22-2014, 12:25 AM
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St. Jude Donor '14
Front RB rotors are in stock and save 7lbs rotating mass and offer a true ring replacement. The rears are being produced now and are about 10 weeks out.
06-06-2014, 08:50 PM
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St. Jude Donor '14
Racing Brake rotor client review
My client in Germany got back to me today after his track outing with some great info on the 2pc RB front rotors and stainless brake lines.
"The two-piece rotor discs, you´ve sent to me are GREAT! That is, what I want to tell you and thank you very much therefore.- They are much better than the factory brakes! Do you already have experience with brake pads, fitting to this brake, which are also for track and street as well?. If yes, pls. let me know!
Kind regards!
Günther"
"The two-piece rotor discs, you´ve sent to me are GREAT! That is, what I want to tell you and thank you very much therefore.- They are much better than the factory brakes! Do you already have experience with brake pads, fitting to this brake, which are also for track and street as well?. If yes, pls. let me know!
Kind regards!
Günther"
08-04-2014, 04:04 PM
#20
Rotational inertia of a brake disc is not very important relative to that of the tire followed by the wheel. Rotational inertia is a function of the mass and the radius squared. Most of the tire's mass is at the outside, so radius = 13 and r^2 = 169 and mass is 27 lbs, so a factor of 4560, and most of the wheel's weight is at its outside with a radius of 9.5 and r^2 = 90 with a weight of 25 lbs, so a factor of 2250, so squaring the radius of each and adding the wheel and tire's rotational inertia quite dominates the effect of a brake lighter by a couple of pounds, whose equivalent radius is about 7.7 and r^2 = 59 with a mass of 20 lbs, so a factor of 1180 out of a total of 7990. If you drop the weight of the rotor by 3 lbs, the rotor's contribution factor drops to 1000, dropping the total to 7800, or 2% drop in rotational inertia. Drop is slightly more if you consider the part of the tire weight is the sidewall, and part of the wheel weight is the spokes, but still not a big effect.
If you want to drop the rotational inertia, start by going to a lighter tire, as that will have much more effect, followed by a lighter wheel.
The unsprung mass benefit is there however, but taking 2-3 lbs off the total of tire plus wheel plus suspension and caliper etc. is not going to have a big effect in terms of % unsprung weight. Tire + wheel + 20 lb rotor = 72 lbs, so dropping 3 lbs off that is not so much.
It is not like there is no benefit, but it is not that big.
If you want to drop the rotational inertia, start by going to a lighter tire, as that will have much more effect, followed by a lighter wheel.
The unsprung mass benefit is there however, but taking 2-3 lbs off the total of tire plus wheel plus suspension and caliper etc. is not going to have a big effect in terms of % unsprung weight. Tire + wheel + 20 lb rotor = 72 lbs, so dropping 3 lbs off that is not so much.
It is not like there is no benefit, but it is not that big.