Hydraulic Disc Brakes

Mountain Bike Hydration Pack Buyer's Guide

Hydraulic disc brakes are the most powerful and reliable braking system available for the modern mountain bike. A high quality set will give trail riders extra confidence when attacking tricky downhill sections, and downhill riders will greatly benefit from high-end disc brakes.

Hydraulic brakes get their power by actuating a piston in the brake lever. This piston pushes fluid through the hose all the way down to the caliper, where a second set of pistons push the brake pads into contact with the rotor. This creates friction, which slows down the wheel. Most hydraulic disc brakes use dual pistons in the caliper, applying pressure on the rotor from both sides. There are also single piston models, and others that use up to six pistons. Brakes are an indispensable part of a mountain bike, and upgrading them will noticeably increase your ride's performance.

Types

Hydraulic disc brake types are differentiated according to their intended riding application, their adjustability, and the type of hydraulic fluid they use. Companies facilitate the selection process by identifying the type of riding each brake model is designed for.

Downhill brakes provide maximum stopping power with a slight weight penalty, cross-country brakes seek minimum weight, and all-mountain brakes find a balance somewhere in between.

Adjustability is a big determining factor in the price of a brake. As the price of a brake increases, external adjustments like lever reach, pad contact and stopping power become available.

Mountain bike brakes use two types of braking fluid: DOT fluid or mineral oil. Like diesel and gas powered cars, brakes designed for one type of oil do not work with the other.

Sizes

Disc brakes come in three standard disc brake rotor sizes: 6, 7 and 8-inch or 160, 180 and 200mm. Larger rotors provide more stopping power and shed heat faster, but smaller rotors are lighter. It is common for riders to mix and match rotor sizes for increased performance. For example, downhillers may use an 8-inch rotor in the front and a 7-inch rotor in the rear. Another common setup for trail riders is 7-inch up front with a 6-inch rear rotor. When changing rotors, keep in mind that every rotor size requires a different brake adapter, which mounts between the frame and disc brake caliper.

Materials

Hydraulic brakes use a combination of materials. Brake lever bodies are made of aluminum or magnesium, brake lever blades come in aluminum and carbon fiber, calipers are made from aluminum or magnesium, and rotors are steel, but may use aluminum spiders.

Things To Look For

Installing a new set of hydraulic brakes can be a very simple and fast process. If the bike they are to be mounted on is equipped with disc hubs and disc tabs on both the frame and fork, then installation is only a matter of bolting the new parts on. To facilitate installation, most manufacturers sell their hydraulic brakes pre-bled with the hoses, calipers and levers ready for installation. Be sure to identify the correct brake adapters for your frame, fork, and brake model. Brake adapters are inexpensive and can be found in most bike shops. Note that there are various types of disc brake pads that are suited to different riding conditions.

How Much To Spend

Hydraulic disc brakes range in price from $80 to $475 per brake, which includes a lever, caliper, hose and rotor.

Models in the $80-$175 range are generally dual piston designs with aluminum or magnesium parts. They have few or no external adjustment and are designed for general mountain bike use, but provide reasonably consistent and reliable performance at a competitive price.

Moving up to the $175-$275 range, brakes begin to incorporate carbon fiber levers, more pistons, sophisticated technology and design techniques, and some kind of external adjustment. These models are designed for specific types of riding and provide lower weight with increased power.

Brakes costing more than $300 are top of the line components that integrate all of the technology available into a lightweight, high performance package. They are designed to deliver ultimate performance for competitive riders.

Product Reviews

Before buying, be sure to do your research and read product reviews. Reviews are a great way to find out specifics about a particular model, user impressions, and things to watch out for. After you've purchased a product and had enough time to thoroughly test it, we encourage you to leave a review for other people to see when they are researching bikes and parts on the web.

We hope you've found this information to be helpful. If you have a question that isn't answered in this guide, our mountain bike forums are a great place to get advice from knowledgeable riders. Your local bike shop is also a great resource.