VTT Ultimate Rear 15” Brake Conversion Kit

BMW E8X / E9X

VTT is proud to introduce our Ultimate Rear 15” Brake Conversion Kit for the E8X/E9X platform.

We took what already exists on the market and made it more complete, more performance-oriented, and purpose-built for drag applications — while maintaining clearance for 15” wheels.

This system replaces your factory rear rotor and single-piston caliper setup with lightweight VTT 4-piston calipers and 15” conversion rotors — dropping up to 20+ lbs of unsprung weight off the rear of the vehicle.

Less weight.
More clearance.
Improved weight transfer.
Better straight-line performance.

What’s Included

• (2) Rear Rotors

  • Plain: Centric 125 Series

  • Slotted: Genuine StopTech

• (2) VTT 4-Piston Rear Calipers

• (1) Set VTT High-Performance Brake Pads (Street or Race)

  • Optional: Order without pads to use your own compound

• All required hardware (brackets, bolts, adapter fittings)

• Optional Stainless Steel Rear Brake Lines

Pad compatibility:

• 4-Piston Dynapro Pad Style 7812

• 6-Piston Dynapro Pad Style 6712
  (Multiple aggressive compounds available from various manufacturers.)

Fitment Notes

• Direct bolt-on for specified E8X/E9X chassis.

• Designed to clear many 15” wheel setups.

• We have confirmed fitment with Weld RTS 15×10 wheels.

• Due to wheel offset and design variations, we cannot guarantee clearance with every 15” wheel configuration.

Required Modification:
Rear brake dust shields must be removed for installation.

Weight Savings Breakdown

Calipers (with pads)

Factory Rear Caliper:
11.5 lbs each

VTT 4-Piston Caliper:
4.5 lbs each

✔ 7–7.5 lbs savings per side
✔ 14–15 lbs total savings (calipers alone)

Rotors

Factory Rotor:
18.2 lbs each

15” Slotted Conversion Rotor:
13.5 lbs each
✔ 4.7 lbs savings per side

15” Plain Conversion Rotor:
14.4 lbs each

✔ 9.4 lbs total savings (rotors vs factory, slotted option)

Total Rear Weight Comparison

Factory Rear Brakes:
~56 lbs total

VTT 15” Plain Rotor Setup:
37.3–37.8 lbs
✔ 18–19 lbs total savings

VTT 15” Slotted Setup:
35–36 lbs
✔ 20–21 lbs total savings

Important Disclaimer

This kit is designed for street use and drag racing only.

It is NOT designed for:

• Auto-X

• Road Racing

• Track use with repeated heavy braking

Always operate the vehicle within your limits.

Bedding Procedure – CRITICAL

Brake pads must be properly bedded to achieve full braking performance.

Failure to bed pads correctly may result in:

• 30–50% braking effectiveness

• Pad glazing

If glazing occurs:

• Remove rotors

• Sand pads

• Re-bed properly

Your kit includes a bedding instruction card. Follow it exactly.

• Free US shipping on orders over $250.
• Free pickup at our Dallas shop, usually ready within 24 hours.
• Unused parts can be returned within 30 days. Tunes, opened electronics, merch and installed parts are final sale.
• Want it installed? Book the install at thegbmotors.com.

Full details are on our shipping and returns page.