StopTech Big Brake Kit for 1999-2006 BMW 3-Series [E46]

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General Benefits of Big Brake Kits

Big Brake Kits give your vehicle that Supercar look and feel, and exceed stock performance in two areas. First, larger rotors increase heat capacity. Second, stiffer calipers and stainless steel lines reduce system compliance.

The key, however, is to increase heat capacity and reduce compliance without upsetting the stock front to rear brake torque ratio. If the brake upgrade you select adds too much front torque (as many do), you reduce your car's ability to utilize the tractive capacity of all of the tires to the maximum practical extent (even on ABS equipped cars) and you therefore create performance sacrifices. In addition, too many pistons or pistons that are too large will make the brake pedal much more difficult to modulate, which limits a driver's control of brake input on the race track.

Advantages of StopTech over other brake upgrades:

  • Shorter Stopping Distances
  • Better Brake Modulation
  • Firmer Brake Pedal
  • Less Brake Fade

Feature Benefit Summary:

  • Balanced Brake Upgrades™ with optimum brake bias offer the shortest stopping distance with the best pedal feel
  • Our patented AeroRotors® with the best airflow available result in better cooling, less fade and longer rotor and pad life
  • The stiffest aftermarket calipers with patented bridge result in better clamping under hard braking and less pad taper
  • Track testing of new applications ensures optimum performance


(4 piston kits with 380mm rotors use ST-45 calipers)
  • Made of Squeeze Forged* aluminum alloy
  • ALL finished parts are 100% leak down and pressure tested to 2500 PSI
  • ST-40 uses standard FMSI D372 pad (VIEW PAD SHAPE)
  • ST-45 uses standard FMSI D609 pad (VIEW PAD SHAPE)
  • Any combination of 8 piston sizes available to match kit to vehicle application
  • Differential piston sizes minimize pad taper
  • Dust boots are standard
  • Weight: 7.94 lb (3.6 kg) unloaded
  • Same caliper used by top Speed® World Challenge and Grand-Am Cup Teams

* Squeeze Forged means that pressure is applied during cooling. This produces a beautifully finished, solid part without porosity.



  • Made of Squeeze Forged* aluminum alloy
  • Patented, bolt-in bridge minimizes caliper compliance for a firmer pedal
  • Stiffest 6 Piston caliper currently on the market
  • Uses standard FMSI D1247 pad (VIEW PAD SHAPE)
  • Can be used on rotors with outer diameter of 328-380mm and thickness of 28-35mm
  • ALL finished parts are 100% leak down and pressure tested to 2500 PSI
  • Uses a popular pad shape readily available in over 15 street performance and race friction compounds
  • Over 19 different piston size combinations available to tune brake torque to the needs of each individual application
  • Differential piston sizes minimize pad taper for longer pad life and a firmer pedal
  • Dust boots are standard for reduced maintenance


  • Made of billet aluminum
  • All finished parts are 100% tested to a pressure of 2500 PSI
  • Uses standard FMSI D961 Pad (VIEW PAD SHAPE)
  • 2 piston opposed design
  • May be added to cars with existing front StopTech kits
  • Piston size adjusted for the application, just like our front calipers
  • Dust boots are standard
  • Weight: 4.4 lb (2 kg) unloaded


What’s included?

  • Calipers
  • 2 piece floating directional AeroRotors with hats (pre-assembled)
  • Stainless steel brake lines
  • Caliper mounting brackets
  • Street performance pads

Caliper Color Options

Calipers are available in the following colors:

Blue, gold and yellow calipers have a 30-45 day lead time and are $200 extra per axle.


Rotors are available slotted, drilled or plain. Drilled rotors are $100 extra per axle.

StopTech now offers an anti-corrosion gold zinc coating for all AeroRotors. The coating benefits customers who live in cold climates where snow and road salt are commonly encountered, and customers who would prefer to not have visible surface rust on the vanes and outer circumference of their rotors. Zinc coating does not have a negative environmental impact like other coatings. Gold zinc coating costs $70 per axle extra.

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Big Brake Kits