Reply to "New brake kit from "Precision Brakes""

Frode,

As a rule of thumb, the biggest rotor diameter you can fit inside a 15" wheel is about 285 mm, inside a 16" wheel is 310 mm and inside a 17" wheel is 335 mm and inside a 18" wheel is 360 mm. There must be a reasonable clearance between the edge of the rotor and the wheel in order for air to flow through the vented rotor. Also, if the clearance between rotor & wheel is too small, the glue on weights used for balancing the tires will be scraped off by the calipers, I have seen this happen. "Doh!"

So the 325 mm rotors will not fit inside a 15" Campy wheel. They will require a 17" wheel.

When shopping for all new brakes, as opposed to upgrading the oem brakes, keep in mind the brakes are a substantial part of the unsprung weight of the vehicle, you want the rotors to be mounted on aluminum "hats", you also want the calipers to be cast from aluminum. Some may argue, but 4 or 6 piston calipers offer superior braking perfomance. Keeping the unsprung weight as low as possible allows the suspension to follow the surface of the road better, enhancing traction and improving the ride quality as well.

Cross drilled rotors look cool, but they offer no performance benefit. Cross drilling has lost favor in racing, rotors are most often slotted these days, as it weakens the rotor less. So the added expense of cross drilled rotors is not justifiable from a performance perspective, but it's worth about 0.2 seconds per lap in "bench racing".

Price wise, the Precision Brakes kit seems to be about as expensive as a Wilwood brake system. The Wilwood system is choice quality stuff.

Your friend on the PIBB, George