Longdaddy
11-24-2013, 09:09 PM
For the past several months, I have worked with Racing Brake to develop an alternative to Brembo’s “Wide Ring” ACR-X rotors. As many of you already know, ACR-X front rotor/pad configuration provides larger friction surface, and accommodates “D1001” shape pad. Brembo caliper, used as OEM on GenVI Vipers, is able to fit both “D968” brake pad (SRT-10/ACR) as well as “D1001” shape pad, so ACR-X setup takes advantage of that by utilizing a wider pad with a differently proportioned ring/hat combo.
I am happy to report that Racing Brake has finalized the development, and is now offering the “ACR-X” rotor ring as a direct replacement to Brembo’s ring. A number of pads are also available (D1001 is a common shape, and nearly any performance brake pad compound can be ordered from a variety of other vendors as well, of course).
The price is more than competitive as well. You can see for yourself here: http://www.racingbrake.com/Rotor-ring-Slot-Viper-ACR-X-08-FRONT-Replacem-p/1406-10-311.htm
Here is some background on how this came about, as well as details on the setup.
Brembo Motorsports 2-piece rotor unit that is supplied with ACR-X, and can be purchased for non-X cars through vendors dealing in Brembo Motorsports parts, is a good rotor that will stand up to heavy track use, as well as repeated high temperature cycles. It does, however, have some disadvantages, mostly centered around noise/vibration during low speed driving (which increases significantly with track heat cycles), and somewhat abrupt initial torque – especially pronounced when using “cold” pads/rotors at track speeds – something that really surprised a couple of drivers that had a chance to try out my ACR. It also wears front pads very aggressively, likely due to material hardness, as well as “J groove” geometry.
Ever since I got the ACR-X rotor setup from PartsRack, I have been looking for an alternative ring which would retain larger pad, can be used with the Brembo hat which I (and many others) had already, and could be a little “friendlier” to street driving in terms of noise/vibration as well as compatibility with dual use pads. So, when the idea of adapting existing line of RB rotor rings to fit ACR-X hats was brought up by Racing Brake, I thought it would be a perfect way to achieve this. I have used their rings in the past, on several vehicles* and always thought they offered a solid value for my money, unlike, for example, StopTech hardware
I am happy to report that the latest version of the rotor which I test fitted last week appears to be a perfect fit for the Brembo Motorsports “ACR-X” hat (I believe an alternative hat is under development as well)
One thing I like about Racing Brake rings, is that the hardware is much simpler. Neither a washer, nor locking compound are required for the assembly/rebuild, and you can use “normal” 8mm socket instead of 4mm hex bit. If you have destroyed multiple 4mm hex bits and ran out of thread locking compound while rebuilding your rotors (especially at the track!) – you will understand why this little detail can make a big difference.
I am really looking forward to testing these rotors (as well as Racing Brake pads I have) at the racetrack; I am hoping to get the car out in the first weekend of December. On the street, they have been working great so far.
*Racing Brake offers StopTech ring replacements in ACR/SRT-10 sizes as well – which are superior in every single aspect of both track and street use to StopTech units, in my experience.
RacingBrake (left) vs Brembo rings
1326
Mounted with ACR rim & Hoosier R6
1328
clearance between pad and hat
1329
Hardware comparison (RB on the left)
1330
Comparison with stock rotors and D968 shape pads
1331
I am happy to report that Racing Brake has finalized the development, and is now offering the “ACR-X” rotor ring as a direct replacement to Brembo’s ring. A number of pads are also available (D1001 is a common shape, and nearly any performance brake pad compound can be ordered from a variety of other vendors as well, of course).
The price is more than competitive as well. You can see for yourself here: http://www.racingbrake.com/Rotor-ring-Slot-Viper-ACR-X-08-FRONT-Replacem-p/1406-10-311.htm
Here is some background on how this came about, as well as details on the setup.
Brembo Motorsports 2-piece rotor unit that is supplied with ACR-X, and can be purchased for non-X cars through vendors dealing in Brembo Motorsports parts, is a good rotor that will stand up to heavy track use, as well as repeated high temperature cycles. It does, however, have some disadvantages, mostly centered around noise/vibration during low speed driving (which increases significantly with track heat cycles), and somewhat abrupt initial torque – especially pronounced when using “cold” pads/rotors at track speeds – something that really surprised a couple of drivers that had a chance to try out my ACR. It also wears front pads very aggressively, likely due to material hardness, as well as “J groove” geometry.
Ever since I got the ACR-X rotor setup from PartsRack, I have been looking for an alternative ring which would retain larger pad, can be used with the Brembo hat which I (and many others) had already, and could be a little “friendlier” to street driving in terms of noise/vibration as well as compatibility with dual use pads. So, when the idea of adapting existing line of RB rotor rings to fit ACR-X hats was brought up by Racing Brake, I thought it would be a perfect way to achieve this. I have used their rings in the past, on several vehicles* and always thought they offered a solid value for my money, unlike, for example, StopTech hardware
I am happy to report that the latest version of the rotor which I test fitted last week appears to be a perfect fit for the Brembo Motorsports “ACR-X” hat (I believe an alternative hat is under development as well)
One thing I like about Racing Brake rings, is that the hardware is much simpler. Neither a washer, nor locking compound are required for the assembly/rebuild, and you can use “normal” 8mm socket instead of 4mm hex bit. If you have destroyed multiple 4mm hex bits and ran out of thread locking compound while rebuilding your rotors (especially at the track!) – you will understand why this little detail can make a big difference.
I am really looking forward to testing these rotors (as well as Racing Brake pads I have) at the racetrack; I am hoping to get the car out in the first weekend of December. On the street, they have been working great so far.
*Racing Brake offers StopTech ring replacements in ACR/SRT-10 sizes as well – which are superior in every single aspect of both track and street use to StopTech units, in my experience.
RacingBrake (left) vs Brembo rings
1326
Mounted with ACR rim & Hoosier R6
1328
clearance between pad and hat
1329
Hardware comparison (RB on the left)
1330
Comparison with stock rotors and D968 shape pads
1331