Product Summary

Universal Fit, Rear Position, 11.75 Inch Rotor Diameter

  • Replace those old drum rear brakes with modern disc brakes using this universal weld on disc brake kit
  • Features GM Metric calipers with massive 2.38" piston size which provide excellent braking in a compact size
  • 11.75" OD vented rotors which are .81" thick ensure cool operation for fade free braking performance
  • This complete kit includes calipers, rotors, brake pads, brake hats, caliper slide bolts, and caliper brackets
  • The 1.59" offset CNC machined aluminum brake hat accommodates 5 on 4-1/2, 4-3/4", and 5 on 5" bolt circles

Comes as a Kit

Key Specs

Bolt PatternMulti: 5 on 4.5" | 4.75" | 5"
Rotor Diameter11.75 Inch
Rotor TypeVented
Caliper PistonsOne

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Speedway Motors 91031932 Details

Replace those old drum brakes with modern rear disc brakes. Mounts .81" x 11-3/4" Pro-lite vented iron rotors and calipers to 3" tube rear end. Complete with rotors, hats, metric calipers (7/16"-20 inlets), brackets, brake pads, caliper brackets and slider bolts.

Hat fits 5 lug hubs with 4-1/2", 4-3/4", or 5" bolt circle.



  • Caliper Brackets (2)
    • Weld onto a 3" axle tube
  • Rotors (2)
    • GM-style .81" x 11-3/4", 8 on 7" bolt pattern
    • Straight vanes, 8 lbs. each
  • Rotor Hats (2)
    • Machined Aluminum, 1.59" offset
    • 3.06" center hole, 6-3/8" I.D., 1/2" stud holes, 1.5 lbs.
  • Rotor Bolt and Nut Kit (2)
  • Caliper Slider Bolts (4)
  • Brake Pads (2 sets)
    • Street compound, little metallic, long rotor and pad life
  • Calipers - 1978-88 GM Metric (L & R)
    • 7/16"-20 inlet
    • Cast iron body, 2.38" single piston
    • Saves 3.5 lbs. per side compared to '69-'77 GM calipers

Speedway Motors 91031932 Specifications

MFG. Part #91031932
BrandSpeedway Motors
Bolt PatternMulti: 5 on 4.5" | 4.75" | 5"
Rotor Diameter11.75 Inch
Rotor TypeVented
Caliper PistonsOne
Caliper FinishNatural
Parking Brake ProvisionNo
Rotor ShapeRound
Hardware IncludedYes
Front Rotor IncludedNo
Front Caliper IncludedNo
Rear Caliper IncludedYes
Front Spindles IncludedNo
Master Cylinder IncludedNo
Brake Booster IncludedNo
Rear Rotor IncludedYes
Rotor Hat Bolt Pattern8 x 7.00"
Rotor Thickness.81"
Thread Pitch7/16"-20
Centerline of Holes5.50"
Sold in QuantityKit
NotesIncludes rotors, rotor hats, caliper brackets, calipers, pads, and hardware.
Rotor Material TypeCast Iron