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Supermiata Boxmount 11.75″ Front Big Brake kit 90-05 MX5

From: $1,260.00

Product Description

“BX1175” Boxmount™ Big Brake kit – Front

11.75 x 1.1″ rotor – Wilwood Superlite caliper

 Patented Boxmount technology reduces lug mount deflection resulting in a firmer pedal and more predictable braking. The Boxmount also allows much greater cooling airflow without sacrificing rigidity. The best cooling and thermal mass of any NA/NB brake system in the world. Works with all years ABS systems. Complete kit, all mounting hardware included. Duct kit optional

Not all BBK’s are created equal. Though 15 years of sprint, time attack and endurance racing (and many victories), we have learned a lot about high performance brake system requirements. Many will focus simply on maximum rotor diameter and lightest weight, but this approach ignores important details. Even small OEM brakes can easily lock Hoosiers once. Increased thermal capacity and mass is needed to sustain repeated maximum braking events. The BX1175 was designed with a focus on thermal capacity, pad life and brake feel. The rotors were chosen not only for the diameter, but for overall thermal capacity. Thick-wall, directional-vane friction rings are now standard. Increased thermal capacity combined with the large pad thickness decreases fade and knock back while greatly improving the life of the pads. The Boxmount brackets decrease deflection, improving feel and consistency under braking. Note that radial mount kits for the Miata must use a cantilevered and unsupported adapter bracket to mate to the lugs on your spindle. Boxmount brackets are actually stiffer than a converted radial caliper assembly. Whether you’re racing the full WRL series or just enjoying your well-built track car on the weekend, the BX1175 provides the best braking performance.

OPTIONAL Brake duct kit now open for pre-order! Use the drop down menu above to add it to your BX1175 order for a 5% discount on the ducts. Learn more about the duct kit here.

Confirmed fit without spacers:
15×11 Jongbloed Series 500
15×10 +25 Jongbloed Series 500
15×10 +25 949 Racing 6UL
15×10 +25 Konig Dekagram
15×9.5 +29 Konig Freeform
15×9.5 +29 KE Motorsport
15×9 +35 Konig Dekagram
15×9 +35 KE Motorsports
15×9 +35 Sparco FF1
15×8 +28 Advan TC4

Wheels that fit with spacers
15×8 +25 Konig Dekagram – 5mm spacer
15×9 +36 Jongbloed – 5mm spacer
15×9 +36 Rota Grid Concave – 5mm spacer
15×9 +35 Advanti S1 – 7mm spacer
15×8 +25 Konig Countergram – 20mm spacer
15×9 +36 6UL (Gen4) – 25mm spacer

WHEEL FIT TEMPLATE  Download and print the template, trace to hard material (plastic, cardboard) and place in your wheel. Wheel fit tool – Use this tool to check brake clearance with your wheel. You can also print your own tool here: https://www.thingiverse.com/thing:4983138

15×10 +25 offset: Fits all brands without spacers 15×9.5: Fits all brands without spacers 15×9: Check with template or confirmed list. Does not fit 6UL. 15×8: Check with template or confirmed list. Does not fit 6UL.


See our brake system FAQ for more information on choosing brake system components for your Miata

  • Wilwood Forged Superlite 4 piston aluminum front calipers, gray anodized
  • Billet CNC 6061 T06 aluminum hats, hub centric
  • 11.75″ x 1.10 Left & Right Directional Vane or optional straight vane competition rotors
  • Braided stainless, orange hoses
  • Billet CNC aluminum brackets, orange anodized
  • Steel Boxmount braces
  • All hardware and instructions included
  • Your choice of 7420 plate pads (20mm), or choose to omit pads
  • (Optional) duct kit

BP-20 base pad an excellent choice for a daily driver that is not focused on competition use. Select one of the upgraded G-Loc compounds for increased performance.  

Compound guide




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