When it comes to automotive design principles and philosophies for competing parts and engineering options, there are always going to be debates and arguments about which type of part or mechanism is best. For example, take diesel vs. gas, turbocharged vs. naturally aspirated, and floating vs. fixed calipers. In the last example, for anyone interested in upgrading their current brakes, there are some important things to consider about both types of braking systems. Before getting into whether or not you should upgrade, it might first be important to understand what the differences are between floating calipers and fixed calipers and how they affect the way vehicle braking is done.
What Are Floating Calipers?
Floating calipers use one or more pistons attached to only one side of the caliper housing that fits over the wheel rotor. The floating caliper has brake pads on each side of the housing, while the brake line fits into the side of the housing the piston(s) is/are on. The caliper is attached to the wheel hub not with bolts, but with lubricated guide pins and enable it to slide smoothly, or float, from side to side.
When you press the brake pedal, the pistons push the brake pad against the rotor. This force also pulls the side of the caliper opposite the pistons toward the rotor. This causes both brake pads to squeeze onto the rotor, despite the pistons only being on one side, creating enough static friction that the vehicle is slowed down.
Floating calipers are the most common on modern vehicles. They are less expensive and easier to make than fixed calipers, which we’ll discuss next.
What Are Fixed Calipers?
On the surface, fixed calipers may seem rather similar to floating calipers. They also consist of a housing that encircles a fraction of the rotor, evenly on both sides. The fixed caliper has a brake pad on each side of the caliper housing, but unlike floating calipers, there are pistons on both sides of the caliper, not just on one side. The brake line runs through the calipers to the pistons. The fixed calipers, unlike the floating calipers, do not move. As the name infers, the fixed calipers are fixed in place over the rotors.
Depressing the brake applies pressure to the pistons on both sides of the calipers, squeezing the brake pads together against the rotor, causing the vehicle to slow down. It is the same end result, but a different and more complex mechanism. Fixed calipers are less common on modern vehicles as a result.
What Are the Benefits of Floating Calipers?
Floating calipers are typically cheaper to replace, since they have fewer moving parts. With one or more pistons on only one side of the caliper, fewer parts means fewer points of failure over time. This is a good selection if you don’t drive your vehicle hard and you don’t plan to spend much on repairing it, maintaining it, or upgrading it. The average driver falls into this category, which is why most vehicles come with floating calipers.
Another benefit is the ease of bleeding the brake fluid out of the brake line leading to the calipers. If there are air bubbles in the brake line, braking will not be as effective. The caliper has a bleeder screw that you can loosen, then pump the air bubbles and old brake fluid out of the caliper and brake line. Since the piston(s) is/are on only one side of the floating caliper, it’s easier to bleed than fixed calipers, where this process must be completed separately for each side. This makes maintenance a little bit easier compared to fixed calipers, which will need to be bled eight times, twice per caliper, rather than four.
The downside, however, is that floating calipers aren’t as durable as fixed calipers. Particularly in harsh climates, the caliper can seize and get stuck in one position. The result is uneven application of force to the brake pads and rotors, and reduced braking performance. For passenger vehicles used for casual daily errands, this may not be a big deal. The lower cost of floating calipers more than offsets needing to replace them more frequently if they seize up. However, for maximum durability and performance, fixed calipers are superior.
What Are the Benefits of Fixed Calipers?
Floating calipers may seem like a more complex design, since they need to be able to slide back and forth on the guide pins to apply optimum braking pressure. Technically, however, fixed calipers are a more complex design. They have pistons on both sides to clamp the brake pads down on the rotor, requiring dual brake lines on each side of the calipers. The main advantage of this configuration is more robust and immediate braking action and increased control compared to floating calipers.
The design of the fixed calipers also ensures even braking application on both sides of the rotor, especially under high stress braking conditions. This makes fixed calipers an extremely reliable option for some drivers, especially in sports cars or race cars. However, fixed calipers are also great for bringing larger vehicles to a halt more quickly and reliably, since they always apply equal amounts of friction to the rotors. While fixed calipers are typically more expensive than floating calipers, they are more durable, which is something to consider depending on the kind of vehicle you drive.
Specialized colors and race calipers can cost you a pretty penny, which is the main reason why they are not used on most vehicles. However, you are paying for quality, and most drivers who need powerful brakes will opt for fixed calipers on high-performance vehicles, where you need reliable brake pressure applied quickly and evenly in a situation where seconds matter.
Choosing the Right Caliper Upgrade
Choosing the right kind of brake calipers for your vehicle boils down to a number of questions you need to ask yourself. Are you driving a high performance vehicle? Are you planning on taking your vehicle to the track? Do you do a lot of towing and hauling in your vehicle? Do you typically like to drive fast on the highway (within the limits, of course)? Do you like driving your vehicle where there are moments where you go fast, but also have to brake hard for sharp turns? Do you typically drive in areas or across terrain where fast braking is required?
If you answered “Yes” to the above questions, then fixed calipers are probably going to be worth the upgrade. However, if the majority of your driving consists of daily errands, basic commuting, or only occasionally going out every now and then, upgrading your brake calipers might seem a bit like overkill. For casual driving, floating calipers are a cost-effective way to go. However, if reliable braking in areas that see a great deal of snow and ice, as well as the resulting salt and sand treatments on the road that can cause floating calipers to seize, a high-quality set of fixed brake calipers can make a world of difference when it’s time to bring the vehicle to a halt evenly and reliably. Like most things in the automotive world, it’s a cost vs. quality decision when it comes to floating calipers vs. fixed calipers. What you’re willing to spend and how you drive will determine which one best suits your driving profile.