Two-Piece Brake Rotors

Do you want to save unsprung weight and give the brake rotor room to expand under heat? Two-piece brake rotors consist of a friction ring and a separate bell, and they are for you if you brake hard on country roads, at track days or with a bigger brake kit.

What does a two-piece brake rotor do?

A two-piece rotor consists of a friction ring that the pads brake against and a bell, typically made of aluminium, that bolts the rotor to the hub. The split design can reduce unsprung weight and let the ring expand more freely when it gets hot. This can reduce stress and the risk of warping. On some models the ring can be replaced on its own, see replacement rings for brake rotors. If you prefer a simpler solution, we also have one-piece brake rotors.

How to choose two-piece brake rotors

• Size: Diameter and thickness, e.g. 355x32 or 380x34 mm, must match your brake caliper and your brake system.
• Position: Front or rear axle and, on rotors with directional cooling vanes, left or right side.
• Surface: Drilled and slotted rotors, e.g. DBA 5000 Series or Brembo Type3, can help channel gas and debris away from the pad. What suits you best depends on use and load.
• Material: Carbon-ceramic rotors such as Brembo's CCM-R typically require matching brake pads.

Compare, for example, rotors from DBA and the Eradispeed+ rotors from Baer Brakes based on size, surface and your project.

Installation and maintenance

Check the fitment for the specific part number, and tighten the bolts according to the manufacturer's instructions. New rotors and pads must be bedded in before you put them under heavy load. Keep an eye out for cracks at the drilled holes, wear on the ring and loose bolts in the bell. Overheating can cause braking performance to fade. A soft or long pedal, on the other hand, is often caused by boiling brake fluid.

Frequently asked questions

What is the difference between a two-piece and a one-piece brake rotor?

The two-piece rotor has a separate bell bolted to the friction ring, while the one-piece rotor is cast as a single piece. The two-piece rotor can weigh less and handle thermal expansion better, but the benefit depends on the rotor and the car.

Are two-piece brake rotors road legal?

It depends on the product and the car. Check for the specific part number whether the rotor has E-mark or R90 approval, and whether the modification requires an inspection. An entire product series is not automatically approved.

Can I just replace the ring when the rotor is worn?

On some two-piece rotors the friction ring can be replaced while the bell is reused, provided it is undamaged. It depends on the design, so check whether a suitable ring is available for your particular rotor. Always replace in pairs on the same axle.