Wheel Size
Wheel size and design have major effects on braking performance and brake fitment. Larger wheels carry greater rotating mass, which reduces braking ability. Hence, bigger rotors and calipers are more of a necessity than a luxury when increasing wheel diameter. In addition to size, wheel design dictates the brake package size. "The last thing you want to do is spend a bunch of money on wheels and tires then realize the brakes you want to install won't fit, so select wheels and brakes together as a package" says Michael. "Large wheel lips reduce the available space for brakes, as can the design of the spokes, so you must take thorough measurements to ensure proper fitment. Determine brake clearance by measuring from the flat spot of the wheel behind the lug-nut holes to the back of the spokes."
Traction And Braking
Everyone's stuck on rotor diameter and caliper piston count, but the importance of tire grip is often overlooked. To prevent excessive lockup, tire traction plays a significant role in overall braking performance. "Adding a big brake kit without upgrading your wheels and tires is like having a big-block car running on bias-plies," Michael quips. "You can't get braking force to the ground with small tires, and it's important to have a sticky compound as well. Having an adequate amount of contact patch is critical, so don't expect a car to stop well with skinnies or cheap tires."
Rotor Diameter
Massive rotors are a hallmark of big brake kits, but how do they factor into the total braking equation? "Larger rotors don't necessarily increase bite over smaller rotors, but like using a longer connecting rod in an engine, they do increase leverage," explains Michael. Additionally, with larger rotors comes greater heat capacity, which helps reduce brake fade. "In essence, rotors are heat sinks. Since larger rotors are usually thicker than smaller rotors, that additional mass prevents heat from transferring into the calipers and fluid."
Floating vs. Fixed Calipers
"In a floating caliper design-which is most commonly used by the OEs-the pistons are only placed on the inboard side of the rotor, and the caliper slides on pins to exert force on the outboard side of the rotor. On the other hand, since a fixed caliper has pistons on both sides of the rotor, the caliper itself does not need to move, just the pistons. A floating caliper is less expensive and will fit more wheels because the design is more compact. They're often a better option in applications with low-end wheels that don't have adequate brake clearance since they fit just about anything. That's why we created a three-piston sliding caliper. The advantage of a fixed caliper is that it exerts equal pressure on both sides of the rotor. Floating calipers tend to have uneven pad wear, since they exert more pressure on inboard side. Also, if the sliding pins aren't maintained, you'll get uneven brake pressure. Generally, fixed calipers are preferred in heavy-duty performance and racing applications."