Slotted rotors- Are they worth it?

So why might you want slotted vs drilled vs blank rotors? What are the pros and cons?

Drilled Rotors

Drilling holes in a rotor serves two main purposes. First is adding more surface area for rotor cooling, and second is to allow gases generated from the brake pads to escape. 

While these are good in theory, they are highly application dependent. Most modern brake pads have very minimal outgasses, thus there isn't a need to vent through the rotor. and with brake ducting and larger rotors are a first line of defense, the minor amount of added cooling from the drilled rotor is usually not needed.  

The downside to drilled rotors, is they ten to be more prone to cracking, as the holes serve as stress points from which cracks can propagate. 

Slotted Rotors

The design intent of slotted rotors is to help keep the pad clean. As the pad continually encounters these slots in the rotors, it gets a fresh, clean edge to work with. This "cutting/scrapping" of the pad ensure a fresh, clean surface is always in contact with the rotor.

Apart from cost, as slotted rotors tend to be more expensive then their smooth variants, the main disadvantage is noise. A traditional slotted rotor can be noisy during braking, as the pad encountering the slots can be a bit like a playing card in a bicycle wheel. Some pad/rotor combos are louder than others.

EBC has done something cleaver with the slot pattern on the USR rotors. The slots are broken up, and offset, which greatly reduces the noise produced.

So how much better is the breaking?

In terms of total breaking power, there is not a noticeable difference in a single braking action. Where we have noticed a difference is in the consistency and longevity of the brake feel with slotted rotors. As the pads are continually being cleaned, the braking feel remains consistent longer then it did with the standard smooth EBC rotors.

For an autocross car, we have enjoyed this aspect! Having the confidence that the brakes will be the same from stop to stop.

For a pure street car, we would still recommend the smooth rotors for their price and quiet operation. However if it's a autocross or track car, these EBC USR Rotors are a nice upgrade!