Hat No: 170-12985

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Big Brake Dynamic Hat - Short Offset
Prod #: 170-12985
Price: $229.38
Big Brake Dynamic Hat - Short Offset 170-12985

Hat Dimensions
Mount Hole Type T-Nut Slot
Rotor Bolt Circle (in) 12 x 8.75
Hat Offset (in) 0.71
Center Reg. (in) 2.78
Hat Type
Material Aluminum
Mount Style Dynamic Mount
Finish Type III Anodize
Weight (lbs) 2.44
Bolt Circle Dimensions
Hat Bolt Circle 1 5 x 4.75
Hat Bolt Circle 2
Hat Bolt Circle 3
UPC Number
UPC 889545042061
Application Info
Application Note Corvette Rear
Hat Bolt Kit Part # 230-6656
Application Note
Application Note Dynamic mount hats are not entended for street use.
Big Brake Dynamic Hat - Short Offset - Product Description

GT Series Dynamic Mount Rotor Drag Hats are engineered to withstand the rigors and demands of extreme motorsports competition. Each hat is precision machined from premium grade aluminum offering high strength with low unsprung and rotating weight. Wilwood T-nuts float within the hat and provide true dynamic mounting of a standard through-hole mount rotors in 8 x 7.00" rotor mount patterns. . The wide load bearing load surface of the T-nut and the straight through-hole mount rotors provide the most durable and accurate method of isolating potential pad engagement harmonics and the in-service thermal variations that occur between the hat and the rotor.


GT Series Dynamic Mount Hats are available in a variety of configurations for use with racing hubs, flanged axles, and several OE applications. Straight bell hats are used for the 6.75" and 7.00" rotor mount patterns. Hats for the larger diameter rotor mo




Rotor Hat Dimensions

Additional Hat Dimensions
Rotor Mount Hole Size (in) T-Nut
Shoe I.D. (in)
Clearance I.D. (in) 7.49
Face Thickness (in) 0.3
Hat Stud Diamenter - BC 1 (in) 0.52
Hat Stud Diamenter - BC 2 (in)
Hat Stud Diamenter - BC 3 (in)
Additional Notes

Wilwood Compatible Rotors

C/SiC Rotors

Rotor Dimensions
Rotor Diameter Range 14 15
Rotor Width Range 1.1 1.25

C/SiC Rotors Rotors

Wilwood's C/SiC rotors are made form a proprietary blend ceramic matrix composite material commonly known as Carbon-Ceramic. C/SiC rotors offer higher thermal conductivity and heat capacity in excess of conventional iron or titanium rotors of similar or even greater weight. Developed to withstand extreme temperatures with the highest possible degree of resistance against distortion, warping, cracking, and wear. The formulation for this composite is a derivative of technology and materials that were significant in the development of the extreme duty military spec rotors that are manufactured by Wilwood. View C/SiC Rotors
Drilled Steel Dynamic Mount Rotor

Rotor Dimensions
Rotor Diameter Range 12.9
Rotor Width Range 0.38

Drilled Steel Dynamic Mount Rotor Rotors

Steel rotors have applications in all types of motorsports. Steel rotors provide a durable lightweight option in applications where sustained temperatures remain in the low to moderate range, and high heat spikes are only observed on an intermittent basis. This could be anything from a hard stopping drag race car at the end of a quarter mile, or a high speed stock car coming in from a qualifier at a super speedway. Steel rotors can also be found in lighter weight open wheel cars such as sprints and modifieds, and a variety of light weight, open wheel road course racers. A special alloy and proprietary manufacturing processes give these rotors high resistance to thermal distortion with excellent friction and wear characteristics against the pads. View Steel Rotors
GT 32 Curved Vane Rotor

Rotor Dimensions
Rotor Diameter Range 15
Rotor Width Range 1.25

GT 32 Curved Vane Rotor Rotors

GT-32 curved vane rotors are built for the extreme conditions of professional motorsports. The superior heat absorption and dissipation characteristics of these heavy wall directional vane rotors are the keys to preventing heat fade and realizing long service life from the rotors and pads. All rotors are cast from premium grade, long grain carbon iron for long wear, thermal stability, and resistance to distortion. Every GT rotor is fully detail machined to eliminate stress points and unnecessary weight away from the pad sweep face. The faces and O.D. are precision turned to less than .001" for flatness, parallelism, and run-out. An asymmetrical face slot pattern provides smoother engagement through reduced harmonics and improved thermal balance between the I.D. and O.D. of the rotor. Every rotor is then individually dynamic balanced to provide vibration free performance at any speed. These rotors provide the highest cooling capacity and longest service life for extreme braking short tracks and road course competition. View GT Rotors
GT 36 Straight Vane Rotor

Rotor Dimensions
Rotor Diameter Range 14
Rotor Width Range 0.81

GT 36 Straight Vane Rotor Rotors

GT-36 straight vane rotors are built for the extreme conditions of professional motorsports. The superior heat absorption and dissipation characteristics of these heavy wall directional vane rotors are the keys to preventing heat fade and realizing long service life from the rotors and pads. All rotors are cast from premium grade, long grain carbon iron for long wear, thermal stability, and resistance to distortion. Every GT-36 rotor is fully detail machined to eliminate stress points and unnecessary weight away from the pad sweep face. The faces and O.D. are precision turned to less than .001" for flatness, parallelism, and run-out. An asymmetrical face slot pattern provides smoother engagement through reduced harmonics and improved thermal balance between the I.D. and O.D. of the rotor. Every rotor is then individually dynamic balanced to provide vibration free performance at any speed. These rotors provide the highest cooling capacity and longest service life for extreme braking short tracks and road course competition. View GT Rotors
GT 36 Straight Vane Rotor

Rotor Dimensions
Rotor Diameter Range 14
Rotor Width Range 0.76

GT 36 Straight Vane Rotor Rotors

GT-36 straight vane rotors are built for the extreme conditions of professional motorsports. The superior heat absorption and dissipation characteristics of these heavy wall directional vane rotors are the keys to preventing heat fade and realizing long service life from the rotors and pads. All rotors are cast from premium grade, long grain carbon iron for long wear, thermal stability, and resistance to distortion. Every GT-36 rotor is fully detail machined to eliminate stress points and unnecessary weight away from the pad sweep face. The faces and O.D. are precision turned to less than .001" for flatness, parallelism, and run-out. An asymmetrical face slot pattern provides smoother engagement through reduced harmonics and improved thermal balance between the I.D. and O.D. of the rotor. Every rotor is then individually dynamic balanced to provide vibration free performance at any speed. These rotors provide the highest cooling capacity and longest service life for extreme braking short tracks and road course competition. View GT Rotors
GT 48 Curved Vane Rotor

Rotor Dimensions
Rotor Diameter Range 12.88
Rotor Width Range 1.1

GT 48 Curved Vane Rotor Rotors

GT-48 curved vane rotors are built for the extreme conditions of professional motorsports. The superior heat absorption and dissipation characteristics of these heavy wall directional vane rotors are the keys to preventing heat fade and realizing long service life from the rotors and pads. All rotors are cast from premium grade, long grain carbon iron for long wear, thermal stability, and resistance to distortion. Every GT rotor is fully detail machined to eliminate stress points and unnecessary weight away from the pad sweep face. The faces and O.D. are precision turned to less than .001" for flatness, parallelism, and run-out. An asymmetrical face slot pattern provides smoother engagement through reduced harmonics and improved thermal balance between the I.D. and O.D. of the rotor. Every rotor is then individually dynamic balanced to provide vibration free performance at any speed. These rotors provide the highest cooling capacity and longest service life for extreme braking short tracks and road course competition. View GT Rotors
GT 48 Curved Vane Rotor

Rotor Dimensions
Rotor Diameter Range 12.88
Rotor Width Range 1

GT 48 Curved Vane Rotor Rotors

GT-48 curved vane rotors are built for the extreme conditions of professional motorsports. The superior heat absorption and dissipation characteristics of these heavy wall directional vane rotors are the keys to preventing heat fade and realizing long service life from the rotors and pads. All rotors are cast from premium grade, long grain carbon iron for long wear, thermal stability, and resistance to distortion. Every GT rotor is fully detail machined to eliminate stress points and unnecessary weight away from the pad sweep face. The faces and O.D. are precision turned to less than .001" for flatness, parallelism, and run-out. An asymmetrical face slot pattern provides smoother engagement through reduced harmonics and improved thermal balance between the I.D. and O.D. of the rotor. Every rotor is then individually dynamic balanced to provide vibration free performance at any speed. These rotors provide the highest cooling capacity and longest service life for extreme braking short tracks and road course competition. View GT Rotors
GT 48 Curved Vane Rotor

Rotor Dimensions
Rotor Diameter Range 12.88
Rotor Width Range 0.81

GT 48 Curved Vane Rotor Rotors

GT-48 curved vane rotors are built for the extreme conditions of professional motorsports. The superior heat absorption and dissipation characteristics of these heavy wall directional vane rotors are the keys to preventing heat fade and realizing long service life from the rotors and pads. All rotors are cast from premium grade, long grain carbon iron for long wear, thermal stability, and resistance to distortion. Every GT rotor is fully detail machined to eliminate stress points and unnecessary weight away from the pad sweep face. The faces and O.D. are precision turned to less than .001" for flatness, parallelism, and run-out. An asymmetrical face slot pattern provides smoother engagement through reduced harmonics and improved thermal balance between the I.D. and O.D. of the rotor. Every rotor is then individually dynamic balanced to provide vibration free performance at any speed. These rotors provide the highest cooling capacity and longest service life for extreme braking short tracks and road course competition. View GT Rotors
GT 48 Curved Vane Rotor

Rotor Dimensions
Rotor Diameter Range 12.88
Rotor Width Range 1 1.1

GT 48 Curved Vane Rotor Rotors

GT-48 curved vane rotors are built for the extreme conditions of professional motorsports. The superior heat absorption and dissipation characteristics of these heavy wall directional vane rotors are the keys to preventing heat fade and realizing long service life from the rotors and pads. All rotors are cast from premium grade, long grain carbon iron for long wear, thermal stability, and resistance to distortion. Every GT rotor is fully detail machined to eliminate stress points and unnecessary weight away from the pad sweep face. The faces and O.D. are precision turned to less than .001" for flatness, parallelism, and run-out. An asymmetrical face slot pattern provides smoother engagement through reduced harmonics and improved thermal balance between the I.D. and O.D. of the rotor. Every rotor is then individually dynamic balanced to provide vibration free performance at any speed. These rotors provide the highest cooling capacity and longest service life for extreme braking short tracks and road course competition. View GT Rotors
GT 48 Curved Vane Rotor

Rotor Dimensions
Rotor Diameter Range 12.88
Rotor Width Range 1.25

GT 48 Curved Vane Rotor Rotors

Wilwood's GT 48 Curved Vane Spec-37 rotors are manufactured from a proprietary iron alloy developed to withstand extreme temperatures with the highest possible degree of resistance against distortion, warping, cracking, and wear. The formulation for this alloy is a derivative of technology and materials that were significant in the development of the extreme duty military spec rotors that are manufactured by Wilwood. Combined with our proven GT Series asymmetrical face slot pattern and individual dynamic balancing, you are assured the smoothest, vibration free performance at any speed. These rotors provide the highest cooling capacity and longest service life for extreme braking short tracks and road course competition. View GT Rotors
GT 48 Curved Vane Rotor

Rotor Dimensions
Rotor Diameter Range 13.06
Rotor Width Range 1.25

GT 48 Curved Vane Rotor Rotors

Wilwood's GT 48 Curved Vane Spec-37 rotors are manufactured from a proprietary iron alloy developed to withstand extreme temperatures with the highest possible degree of resistance against distortion, warping, cracking, and wear. The formulation for this alloy is a derivative of technology and materials that were significant in the development of the extreme duty military spec rotors that are manufactured by Wilwood. Combined with our proven GT Series asymmetrical face slot pattern and individual dynamic balancing, you are assured the smoothest, vibration free performance at any speed. These rotors provide the highest cooling capacity and longest service life for extreme braking short tracks and road course competition. View GT Rotors
GT 60 Curved Vane Rotor

Rotor Dimensions
Rotor Diameter Range 15
Rotor Width Range 1.25

GT 60 Curved Vane Rotor Rotors

Wilwood's GT 60 Curved Vane Spec-37 rotors are manufactured from a proprietary iron alloy developed to withstand extreme temperatures with the highest possible degree of resistance against distortion, warping, cracking, and wear. The formulation for this alloy is a derivative of technology and materials that were significant in the development of the extreme duty military spec rotors that are manufactured by Wilwood. Combined with our proven GT Series asymmetrical face slot pattern and individual dynamic balancing, you are assured the smoothest, vibration free performance at any speed. These rotors provide the highest cooling capacity and longest service life for extreme braking short tracks and road course competition. View GT Rotors
GT 72 Curved Vane Rotor

Rotor Dimensions
Rotor Diameter Range 14 15
Rotor Width Range 1.1 1.25

GT 72 Curved Vane Rotor Rotors

Wilwood's GT 72 Curved Vane Spec-37 rotors are manufactured from a proprietary iron alloy developed to withstand extreme temperatures with the highest possible degree of resistance against distortion, warping, cracking, and wear. The formulation for this alloy is a derivative of technology and materials that were significant in the development of the extreme duty military spec rotors that are manufactured by Wilwood. Combined with our proven GT Series asymmetrical face slot pattern and individual dynamic balancing, you are assured the smoothest braking available. View GT Rotors
HD 48 Curved Vane Rotor

Rotor Dimensions
Rotor Diameter Range 12.88 13.06
Rotor Width Range 1.25

HD 48 Curved Vane Rotor Rotors

Wilwood's HD 48 Curved Vane Spec-37 rotors are are manufactured from a proprietary iron alloy developed to withstand extreme temperatures with the highest possible degree of resistance against distortion, warping, cracking, and wear. The formulation for this alloy is a derivative of technology and materials that were significant in the development of the extreme duty military spec rotors that are manufactured by Wilwood. Our HD Series preparation includes full detail machining and smooth pad contact faces without slots. View HD Rotors
SRP Drilled Performance Rotor

Rotor Dimensions
Rotor Diameter Range 14
Rotor Width Range 0.81

SRP Drilled Performance Rotor Rotors

SRP Drilled Performance Rotors feature a specially engineered directional cross drill and face slot pattern that improve brake response and pad performance throughout the entire range of light to heavy braking. The venting and cleaning action of the holes and slots will reduce pad glaze and disperse gasses and heat generated during the pad to rotor interface. The holes and slots also inhibit irregular pad compound build-up on the rotor faces resulting in smoother engagement and improved pedal response in all conditions. The material removed also contributes to lower rotating and unsprung suspension weight. View SRP Rotors
SRP Drilled Performance Rotor

Rotor Dimensions
Rotor Diameter Range 14
Rotor Width Range 0.76

SRP Drilled Performance Rotor Rotors

SRP Drilled Performance Rotors feature a specially engineered directional cross drill and face slot pattern that improve brake response and pad performance throughout the entire range of light to heavy braking. The venting and cleaning action of the holes and slots will reduce pad glaze and disperse gasses and heat generated during the pad to rotor interface. The holes and slots also inhibit irregular pad compound build-up on the rotor faces resulting in smoother engagement and improved pedal response in all conditions. The material removed also contributes to lower rotating and unsprung suspension weight. View SRP Rotors
SRP Drilled Performance Rotor

Rotor Dimensions
Rotor Diameter Range 12.88 15
Rotor Width Range 0.75 1.25

SRP Drilled Performance Rotor Rotors

SRP Drilled Performance Rotors feature a specially engineered directional cross drill and face slot pattern that improve brake response and pad performance throughout the entire range of light to heavy braking. The venting and cleaning action of the holes and slots will reduce pad glaze and disperse gasses and heat generated during the pad to rotor interface. The holes and slots also inhibit irregular pad compound build-up on the rotor faces resulting in smoother engagement and improved pedal response in all conditions. The material removed also contributes to lower rotating and unsprung suspension weight. View SRP Rotors
SRP Drilled Performance Rotor

Rotor Dimensions
Rotor Diameter Range 12.88 14
Rotor Width Range 1.1

SRP Drilled Performance Rotor Rotors

SRP Drilled Performance Rotors feature a specially engineered directional cross drill and face slot pattern that improve brake response and pad performance throughout the entire range of light to heavy braking. The venting and cleaning action of the holes and slots will reduce pad glaze and disperse gasses and heat generated during the pad to rotor interface. The holes and slots also inhibit irregular pad compound build-up on the rotor faces resulting in smoother engagement and improved pedal response in all conditions. The material removed also contributes to lower rotating and unsprung suspension weight. View SRP Rotors



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