SOT 13x1.25" Rotor '4R' Forged Aluminum Caliper System - Trailing Mount

Score: 5.00 (votes: 3)
Reviews: 3
  • $2295.00

This maximum performance system is a must for serious street machines and high horsepower track cars. Utilizing a deeper hat offset this system is a direct bolt on to factory and SOT Big DRUM & DISC spindles and requires no wheel spacers to fit a 17" or larger Torq Thrust II style wheel.


13x1.25" Rotor 4 Piston Forged Aluminum Caliper Brake System
Disc brake conversion kit for 1964-73 Mustangs and other Fords.

Available for factory and SOT Big 65-73 DRUM, 68-73 DISC & 75-80 Granada spindles.  Retains OE track width.



Offering maximum performance this system is a must for serious street machines and high horsepower track cars.  Utilizing a deeper hat offset this system is a direct bolt on to factory 65-73 DRUM, SOT Big, 68-73 DISC & 75-80 Granada spindles.  No wheel spacers are required to fit a Torq Thrust II or a Vintage Wheel Works 17x8 style wheel.


This complete brake system offers the highest level of performance available.  Using heavy duty directional vane 13 x 1.25" rotors that mount to an aluminum hat, this system offers great weight savings and exceptional cooling.  Stress flow forged aluminum calipers with 4 stainless steel pistons accept .800" thick pads in a variety of compounds. 


Now featuring our Billet Steel Hubs!

hub2_3.jpgClick HERE for more information.

This video discusses our 13x1.25" Front Brake System for the 1965-73 Mustang and similar Fords. Fits all 65-73 Mustang style DRUM and DISK spindles.  Also fits 75-80 Granada spindles.  Requires 17" wheels or larger.

Please download and use the wheel fitment template:


Kit includes:

  • 2 x Forged aluminum 4 piston calipers, powder coated bright red or gloss black.
  • 2 x 13" x 1.25" 2-piece heavy duty rotors with 36 directional cooling vanes that mount to aluminum hats.
  • 2 x Billet steel hubs machined from heat treated 4140.  Screw on dust caps included (stock type dust cap can also be used if desired).  Fitted with bearing races and standard length wheel studs (so you can use closed end lug nuts).  3" long ARP studs and open ended lug nuts available as an optional extra.
  • 2 x Billet spindle/caliper mounting brackets.  CAD designed and CNC machined.
  • 2 x Timken inner bearings.
  • 2 x Timken outer bearings.
  • 2 x Timken inner dust seals.
  • 2 x Stainless steel braided brake hoses complete with all adapters to connect to caliper and stock hard lines.  Hoses meet DOT MVSS-106 requirements.
  • 2 x Castle nuts (70-73 spindles use nut and castle style nut retainer).
  • 2 x Cotter pins.
  • Grade 8 bolts and all the hardware to install the kit.

Optional components:

  • ARP 3" long wheel studs
  • Big spindle kit


 All kits are custom built to your exact specifications.  If you are in a rush, please contact us to confirm current build time

General Specifications:
Wheel Size Required:Fits 17" & larger wheels - please use template shown above


Caliper Specifications:
 Description:Forged Aluminum 4 Piston
 Number of Pistons:4 - Stainless
 Piston Size:1.62"
 Construction:Stress flow forged from premium grade aluminum alloy billets.  This process re-aligns the metals internal grain structure to flow within the contour of the caliper body.  This process eliminates the stresses and interruptions to the internal grain structure that occur when machining a straight block.  This results in a stronger and stiffer caliper.
 Pads:Continuing the performance trend of this system, this caliper uses a huge pad.  Each pad is 0.800" thick, has an area of 8.2 square inches and a volume of 4.9 cubic inches.  That is almost as thick as a stock Mustang rotor!  Thick pads not only last a long time, they offer insulation from the heat of the rotor transmitting to the pistons and ultimately the fluid.  Pad changes are super easy, simply remove the center bridge bolt and pull out the pads.

Compound Information


  • Medium friction, smooth engagement, low abrasion.
  • Flat torque curve.  Maintains a coefficient of friction between .40 from cold peaking at .45 around 700F degrees.
  • Beds quickly and provides fast response without excessive abrasion.


  • High friction, smooth initial response, low wear rate.
  • Medium to high friction with good cold response.
  • Smooth, predictable engagement. 
  • Long wearing pad in the middle temperature ranges with only moderate wear in sustained high heat conditions.
  • Peak coefficient of friction of .63 is reached at only 400F degrees and is almost flat all the way to 1300F degrees.
 Finish:Powder coated bright red or gloss black - other custom colors available.
 Notes:Each caliper is equipped with replaceable stainless steel bridge plates. These plates eliminate the bridge wear caused by pad gouging and extend the service life of the caliper body. The spring-loading action of the plates also eliminates pad rattle and dampens the vibration harmonics that contribute to squeal under braking. Other standard features include high-temperature, square faced o-ring seals for positive sealing, controlled piston retraction, and long service life in high heat conditions. Stainless steel pistons are used to resist corrosion and retard heat transfer from the pads. Two-piece bleed screw assemblies provide long, reliable service life and are easily replaced if necessary. 

Caliper is mounted rearward of the spindle upright (trailing).  This position makes routing brake duct hose in from the front of the car super easy.

Fully assembled caliper with pads weighs 7.2lbs.

Use 1" bore master cylinder for perfect pedal height/pressure like #HERE.


Rotor Specifications:
Type:Heavy Duty 2 Piece mounts to CNC machined billet aluminum hats.
 Venting:36 Directionally vented vanes
 Finish:Plain or Gas vented slots
 Note:We use only quality, heavy duty castings cast and machined in North America.  Many cheaper 'offshore' rotors are poorly cast and may contain inferior materials and air pockets.
Why use such a large rotor?  Well, simply put, heat.  The friction created by braking creates heat and the more and harder you brake the more heat is generated.  All that heat has to go somewhere and if the 'heat-sink' (rotor) gets so hot it can no longer absorb and shed heat then the heat will conduct and convect to other components.  These other components will include brake fluid and wheel bearings, not places you want increased heat.  The problem with large rotors is weight.  All that weight is unsprung which will affect suspension performance and increase stopping distances.

The rotor we use in this kit provides the best of both worlds.  Increased thermal mass due to its diameter and thickness yet lighter weight when mounted to an aluminum hat.  Maximizing the size of the aluminum hat and minimizing the iron rotor ring to only the pad swept area reduces the weight of the entire rotor/hat assembly to only 15lbs per side.  That is 3lbs lighter than our 13x1.1" one piece rotor.   The wide air gap of this rotor promotes more airflow and sheds massive amounts of heat keeping brake temperatures in check.


Caliper mounting brackets:

Meticulous attention to detail and advanced computer modeling techniques ensure perfect fit.  Our brackets are custom CAD designed, CNC machined, then plated for corrosion protection.


Advanced and professional CAD and CNC tools are used to ensure strength and durability.



Customer reviews
Average rating:
5.00 (Votes: 3)
Rating of votes (3)
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  • Brian A.
    I just got done installing the 13X1.25" brake kit from Street or Track on my 1970 Mach 1. Everything went together as if the parts were original equipment for the car. I can tell a lot of time has gone into researching quality parts, and making things fit properly. I also installed the 11.65" rear Disc kit, and was again impressed by the quality of the fit. Braking performance is so improved, I feel much more confident in the overall performance of the car. The car stops like my old Cobra R. It's AWESOME.

    Both brake kits clear my 17" Vintage Wheel Works V48 wheels with PLENTY of room! This was the ONLY 4 piston system I found that clear these wheels.

    Shaun is also a great source of information, and technical advice. A BIG thanks to Street or Track for designing such AWESOME gear.
  • Steve R.
    Hey Shaun,

    The kit is installed. I'm very impressed with the fit and finish and choice of components. Based on that, I will be ordering the rears next month. The braking feels very good.
  • Steve E.
    Had the brakes and suspension installed on the car and wow, it’s pretty nice. The ride and handling of the car is amazing.

This video discusses our 13x1.25" Front Brake System for the 1965-73 Mustang and similar Fords. Fits all 65-73 Mustang style DRUM and DISK spindles.  Also fits 75-80 Granada spindles.  Requires 17" wheels or larger.

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