Brakes are absolutely essential parts of our mountain bikes, but they’re often absolutely bewildering. How can something with such a simple function of stopping our bikes be so complex?
Having the wrong brakes can make for nervous rides and even cause crashes, so we all must understand what brakes we need. Here, we’ll examine how brakes work and what technologies are used in a way that we can all understand.
What’s a hydraulic disc brake?
First, we need to know what we’re dealing with. Hydraulic disc brakes work by pulling a lever that moves the brake fluid through the brake hose to the brake caliper. The fluid then causes the pistons in the caliper to push the brake pads against the brake rotor, giving us the friction needed to slow down and stay in control.
What hydraulic brake is best for you?
Your brake choice comes down to what you ride and how you ride. Downhill riders slashing berms and hammering through steep and deep sections will use different brakes compared to XC riders who spin their way up climbs and have shorter, flatter descents. Downhill riders need as much stopping power as possible, while the XC rider will be more focused on weight–both need to choose their pads carefully, amount of pistons, and rotors.
MTB rotors explained
The rotors are a key part of the braking system. They’re the link between the brake and the bike and massively impact performance. MTB brake rotors come in various sizes: 140mm, 160mm, 180mm, 203mm, and 220mm, but bigger doesn’t always mean better. Instead, it’s all about ensuring the right amount of heat is generated. If your rotors are too hot, they won’t perform, and the same goes if they’re too cold; we want to find the sweet spot where friction is being created, but the rotors aren’t overheating.
Bigger riders, riding at higher speeds on steep terrain, will be best suited to larger rotors, and smaller rotors are for riders at lower downhill speeds on flatter terrain. You’ll also see some riders with a more oversized rotor on the front and a smaller one on the back. What’s that all about? Because we’re usually hurtling downhill on a steep decline, our weight is loaded towards the front of the bike, making the front brake work more, sometimes doing up to 70% of the braking. A larger rotor is better suited to this job.
The color of your brake rotors can tell you if they’re the right size or not. You're in the sweet spot if they’ve got brown marks on them. Rainbow coloration means they’re running too hot, and you might need to size up, and no discoloration means they’re not getting up to temperature, so you might need to size down–or ride faster.
Our new RT-CL900 and RT-CL800 brake rotors
The new RT-CL900 and RT-CL800 pack as much tech and performance as possible into a rotor. These rotors differ from the previous models because of their new shape, as the thinner profile means there’s less offset and wobble, which improves heat dissipation and braking consistency. The RT-CL900 comes with dissipation paint that gives a 10% improvement. Both are available in 140mm, 160mm, 180mm, and 203mm sizes so every type of rider can find the right setup.
Pistons and pads matter, too
2-piston brakes, unsurprisingly, use two pistons (one on either side of the caliper) to push the pads against the rotor. 4-piston brakes have more pistons and use bigger brake pads with a larger surface area for more stopping power. But size isn’t the most crucial factor; you should keep the sweet spot of heat in mind instead.
Brake pads have two main options: metal (sintered) or resin (organic). Metal brake pads are a good choice for riding in sand, mud and bad weather. In hilly areas that are not too steep, and wintertime, metal pads prove themselves to be a reliable choice. Resin pads are recommended in both dry and wet conditions, and in mountainous areas with long descents—with a slightly faster fading than metal pads.
Fight fading brakes with ICE TECHNOLOGY
When our brakes overheat, we lose stopping power and begin to fade. This isn’t much use when you’re lapping a bike park and staring down another techy descent. ICE TECHNOLOGY rotors use a three-layer construction of stainless steel, aluminum, and stainless steel to get rid of the heat and give you predictable and consistent braking performance. This technology is available across the following disc brakes:
- RT-CL900
- RT-CL800
- RT-MT900
- RT-MT905
- RT-MT800
- SM-RT900
- SM-RT800
- SM-RT86
- SM-RT70
ICE TECHNOLOGIES FREEZA dissipates even more heat
ICE TECHNOLOGIES FREEZA takes our existing ICE TECHNOLOGY rotors and turns the heat dissipation up a notch for riders pushing their bikes to the limit. Expect up to a 50℃ reduction in heat build-up thanks to radiator fins and three-layer design. Check out our XTR and XT rotors for this technology.
SERVOWAVE brings quick engagement
Put yourself in full control with incredibly quick pad engagement thanks to SERVOWAVE. With this technology, less lever movement is needed to move the pads which also helps to get rid of that linear braking feel. Instead, these brakes have a progressive feel with no initial hard bite when you pull the lever.
Easier maintenance with ONE-WAY BLEEDING
Air bubbles in your brake fluid can be a disaster, severely impacting performance, so we’ve created ONE-WAY BLEEDING. This simplified way of routing oil through the system reduces the chance of making a mistake when bleeding your brakes. We recommend using our own in-house Shimano brake mineral oil, which has a number of benefits over DOT fluid. It’s got a high and, vitally, constant boiling point, which helps improve performance under heavy workloads—staying consistently at 200° without absorbing water. It’s also non-corrosive, means it doesn’t damage the plastic or paint on your bike. Finally, Shimano brake mineral oil is more friendly to the environment.
Get the perfect fit with reach adjustment
Having your levers in the right spot to suit your hand size and preference makes mountain biking more comfortable. The reach adjustment dial lets you find your preferred distance between your bars and levers.
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