This subject is one that confuses a lot of people. The thing about rotors is that you can't install a LARGER rotor than what comes on your car without upgrading the calipers as well. You have to bolt on the same-sized rotor as the one that's already on there. In general, if you don't change the rotor size (and mass), you are not going to change the performance of your braking system. So why upgrade, then?
There are a couple of reasons. One is just to go with better quality rotors. Premium rotors will be double-disc ground, which is a special machining method that makes for a very flat rotor surface. Our highest-quality rotors also may use special iron alloys that are more durable, and maybe heat treating for even more longevity compared with standard rotors. None of these make the car stop better, but a flat and true rotor made of the highest-quality iron will give you a long life of secure stops.
Another popular feature found in the premium rotor world is cross-drilling and slotting. Both of these accomplish basically the same thing, which is to allow gases to escape from between the rotor and brake pad. These days, brake pads are fairly stable and don't produce a lot of gas, even when they get really hot, so this probably is not as important as it used to be. We do NOT sell cross-drilled rotors, though, because the holes can develop stress cracks around them, and we have found that this significantly shortens the life of the rotor. Since slotting provides the same benefits without the crack-prone holes, we offer slotted rotors, not drilled ones.
We stock Stoptech and DBA rotors, and have just about every performance Subaru application there is.
Mach V Motorsports
45690 Elmwood Court, Suite 170
Hours (Eastern time)
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