Regardless of what you drive, there is no shortage of available aftermarket brake kits. Choosing which is best for your ride involves looking at a number of factors, including brake disc construction. Generally, there are three types of discs: drilled, slotted and vented. To help narrow down the field, we’ve put together the advantages and disadvantages of each, and which you ultimately should choose.
When you think “big brake kit”, this is probably what you picture. Cross-drilled rotors look very sharp, and you’ll find them on many high-end speed machines like BMW M cars, Ferraris, Lamborghinis, etc. What’s the point of drilling through a rotor? If we go back several decades, brake pads were made of compounds that produced gasses under heavy application. This gas came between the pad and rotor, limiting braking performance. By drilling holes in the rotor, this gas was able to escape, increasing stopping power.
Here’s the issue: brake pads have become substantially better over the years, to the point where those gasses no longer are a problem. So why are high-performance cars still rocking drilled rotors? They look amazing. Unfortunately, the cons now outweigh the pros. Those holes inherently compromise structural integrity and can ultimately lead to premature rotor failure. This explains why modern race cars typically run with solid, not drilled discs. Do they look cool? Incredibly. Are they the best choice performance-wise? Not exactly.
The theory behind slotted rotors is essentially the same as their drilled counterparts. Instead of holes, the slots in the disc’s surface allow for any gasses to escape. Additionally, they can help to clean off any dirt on the brake pad and disperse water. Compared to drilled rotors, slots do not compromise the strength of the disc and fractures are far less likely. Though the benefits of slots are marginal, they come without the sacrifice of possibly shortened rotor life.
If you’re looking for a high performance option that is cost-effective for both track work and daily use, slotted discs are a solid option. When narrowing down manufacturers, make sure the discs are vented as well as slotted. Speaking of which…
No matter which system you end up choosing, there will always be a constant enemy: heat. Rotors experience massive temperatures under heavy braking, which if not limited, can cause reduced performance and increased wear. Beyond routing ambient air to your brakes via cooling ducts, vented rotors can help extract a surprising amount of heat.
The principle is simple: by providing channels for air to escape, hot air is removed while cooler air is cycled through. When combined with either high-quality solid or slotted rotors, internal vents both help reduce fade and increase overall rotor life.
Which to Buy
Drilled rotors are undeniably cool to look at but offer benefits that only apply to pads from decades past. When you factor in the consequences of decreased surface area and possible stress fractures, they begin to make less sense from a performance viewpoint. Instead, we highly recommend going with a quality set of slotted, vented rotors. They look the part, greatly decrease stopping distances and can hold up to longer sessions at the track. That combination is hard to beat.