Basic Guide: Introduction to Brakes
Few things are more important on a bicycle than the brakes. However, with new evolutions in braking systems coming around every few years, sometimes it can be difficult to figure out what’s what, and which system is best for your needs.
Bicycle brakes can broadly be broken up into two basic categories: rim brakes and disc brakes. Rim brakes operate by using calipers mounted on the fork and seatstays to squeeze against a brake track on the wheel rim. Disc brakes use a caliper attached to the left fork arm and rear wheel dropout to squeeze a metal disc rotor attached to the wheel hub. Within each of these categories, there are several types of brake designs. Below, we’ll break down the differences to make things a little clearer.
Some quick terminology:
- Power: power refers to how much power the brake caliper is able to apply to the braking surface. More powerful brakes will be able to stop your bike more quickly.
- Modulation: modulation refers to how controllable the brakes are. A properly adjusted brake should give you access to the full range of braking power, from “feathering” the brakes to slow down, to being able to fully apply the brakes in an emergency.
- Actuation: the movement of the brake mechanism
Quick Warning: Do not attempt to use rim brakes with a disc wheel, or disc brakes with a non-disc brake wheel. This will result in negligible braking performance, will heavily damage the wheel, and could result in injury or death. If you are unsure if your wheel and brake systems are compatible, contact our tech support service at 800 553-8324 (TECH) before riding.
As we said above, rim brakes use a set of calipers to squeeze the wheel, thereby generating friction and slowing it down.
- Road Calipers: these are the most common type of brakes you’ll see. Each caliper is a single unit that mounts to a hole drilled in the fork crown and the seatstay bridge, and they are connected to the brake levers via a cable—one for the rear and one for the front. When the lever is pulled, the brake squeezes the brake track on the wheel rim, producing friction to slow the bike. Modern road calipers feature a dual-pivot design, meaning that the brake pivots in two places to contact the rim, which makes them more powerful and easier to adjust than older mono-pivot models.
- Cantilever Brakes: This is an older style of brakes that is still popular for cyclocross. Cantilever brakes use two independent calipers on either side of the wheel, connected by a wire harness in between. They are most often found on older mountain bikes and cyclocross bikes. Cantilever brakes can offer more powerful braking performance than road calipers, as well as clearance for bigger tires, and muddy tires. They are notoriously hard to adjust, and require a frame with cantilever studs or mounts, but offer many performance benefits for those who need more clearance.
- V-Brakes (also called Linear Pull Brakes): Perhaps the second most common type of brake out there, linear pull brakes were invented by Shimano to address some of the issues with cantilever brakes. Like cantilever brakes, linear pull brakes utilize two independent calipers connected by a wire. However, because the cable pulls directly on the brakes instead of on a wire harness, they offer better modulation and more powerful performance than cantilevers. They also require a frame with cantilever studs or mounts. Standard linear pull brakes are designed to be used with short pull levers like you would find on a mountain bike, and require an adapter to be used with road levers. Mini v-brakes are a recent innovation, and can be used with road levers, since they have a shorter lever pull ratio.
Disc brakes were first introduced on mountain bikes, before slowly making their way to cyclocross bikes, and in the last year or two, road bikes. Disc brakes work by using a caliper to squeeze a metal rotor attached to the hub, much like a car or motorcycle. Because the braking action is closer to the center of rotation, disc brakes are inherently more powerful than rim brakes, and are less affected by bad weather.
- Mechanical Disc Brakes: Mechanical disc brakes are available for mountain bikes, road bikes and ‘cross bikes. Like rim brakes, they use a cable to actuate the brake caliper, however that’s about where the resemblance stops. These brakes use a single caliper on the lower left fork arm and the left side rear drop out to squeeze a metal rotor attached to the hub. There are a few different standards in use for mounting both the disc brake rotors and calipers, so double check with your manufacturer before ordering replacement parts. Disc brakes can only be used with frames and forks that have disc mounting tabs, and with wheels that have disc-ready hubs.
Hydraulic brakes are fairly new, and operate in a fundamentally different way from traditional brakes. Instead of a cable, hydraulic brakes have a hose filled with a fluid (usually mineral oil) that connects from the brake lever to the brake caliper. As you move the brake lever, a piston changes the pressure inside the hydraulic line, forcing the brake to actuate. This has several advantages: hydraulic brakes have better modulation, since there are no cables to stretch; they are unaffected by weather or grime; and the braking action is more powerful since the hydraulic fluid acts as a force multiplier. This makes hydraulic brakes almost ideal for nearly all riding situations, however there is a weight penalty, and hydraulic brakes are more difficult to maintain and service than traditional systems.
- Hydraulic Road Calipers: Introduced in 2013, these are a fairly new innovation, and are offered only by SRAM, Shimano and Magura-- with newer systems expected to be coming from Campagnolo, TRP, and others in 2014. Like standard road calipers, when the lever is pulled, the brake squeezes the brake track on the wheel rim, producing friction to slow the bike. However, the braking action is more responsive and more powerful, thanks to the hydraulic system. This makes hydraulic road calipers ideal for riders who like descending, riding in the rain, tandems, or heavier riders that may need more powerful brakes.
- Hydraulic Disc Brakes: Hydraulic disc brakes have become the gold standard for braking in recent years. These systems are fundamentally similar to mechanical disc brakes, except they use a hydraulic system instead of a cable to apply the braking force. Hydraulic disc brakes are ideal for almost all applications, which is why they’ve been on mountain bikes for several years, and are quickly making their way to road and cyclocross bikes. The only downside (for road/cross) is that they systems are still new, so they are slightly cumbersome and add a bit of weight over road calipers, however that is likely to change in the coming years. Disc brakes can only be used with frames and forks that have disc mounting tabs, and with wheels that have disc-ready hubs.