Bike Brakes Buying Guide

Finding the best bike brakes for your road bike or mountain bike is one of the key component decisions you’ll make when buying or upgrading your bike.

Choosing from hydraulic brakes, caliper road brakes, or disc brakes for a road or mountain bike can be a complex task, but this guide should simplify your decision, and help you make the right choice for you, your bike, and your riding style.

Bike brakes at a glance:

Disc brakes are now the most common style of brakes used by gravel, road cyclists and mountain bikers. While there are dozens of different types of bike brakes available, the ones you need to worry about fall under two main categories: rim brakes and disc brakes.

• Rim brakes, as the name suggests, use the wheel’s rim as a braking surface, slowing down the bike when the brake pads are compressed against it. Rim brakes are widely used on road and commuter bikes and are particularly favoured for their light weight and mechanical simplicity. There are many different types, the main ones being caliper and cantilever brakes, with each one offering advantages and disadvantages depending on what type of riding you are doing.

• Disc brakes, instead of using the rim as a braking surface, disc brakes use a circular metal disc mounted on the wheel’s hub. This disc rotates through a caliper, which contains the brake pads. Squeezing the brake lever, the pads are applied to the rotor, slowing down the bike. Disc brakes are either mechanical, where the caliper pistons are activated with a wire cable, or hydraulic, where compression of hydraulic brake fluid in sealed hoses is used to move the pistons and pads.

Because the braking surface is away from mud and wet (leading to improved braking performance and prolonging the life of your rim), disc brakes have all but replaced rim brakes as standard issues on MTBs and gravel bikes. As technology advances and materials become lighter, disc brakes also now dominate the world of road and cyclocross bikes.

Types of Bike Brakes

In this guide, we will cover the following types of bike brakes:

• Disc Brakes
• Rim Brakes
• Road Bike Brakes
• CX & gravel bike brakes
• Mountain bike brakes

Disc Brakes

Once the preserve of only high-end bikes that carry a hefty price premium and a weight penalty, disc stoppers are now standard on all but the most budget bikes. Advances in materials technology have resulted in reduced weight and improved performance for the most demanding riders and racers across all disciplines.

How do disc brakes work?

All disc brakes are operated with a handlebar-mounted brake lever. The disc brake calipers are at the business end of the brake system with front brake calipers mounted close to the bottom left leg of your forks, and back brakes bolted securely to the rear left seatstay on the rear wheel. A circular metal rotor is attached to each wheel hub, the outer strip running through the brake caliper acting as the braking surface.

While there are differences in how individual brake systems work, the principles are generally the same. Inside the brake caliper are a number of pistons – usually two, one for each side of the disc brake rotor – to which the brake pads are attached. Pulling on the levers will result in the pistons moving inwards, towards the rotor, and the brake pads making contact with the surface. The resulting friction is what stops or slows the wheel spinning.

Why disc brakes?

Disc brakes carry two main advantages over v-brakes or traditional cantilever brakes. Firstly, moving the braking surface away from the rim to a hub-mounted rotor keeps it clear of water and mud. This means a vast improvement in stopping power and reliability when things turn damp – compared to the ‘haul-and-hope’ experience v-brakes occasionally present in wet weather – but also an end to having your wheel rim and rubber pads constantly chewed by a grinding paste of gritty crud, thus lengthening the life of your kit.

Secondly, disc brakes offer great improvements in terms of pure performance over their rim-brake rivals, with much-improved levels of stopping power. While V-brakes still have their fans, most cyclists have now embraced the multiple performance and longevity advantages of the modern generation of disc anchors.

Which disc brake should I buy?

Disc Brake Types

There are two main types of disc brakes – mechanical (in which the piston is activated by a wire cable, like on a rim caliper or v-brake) and hydraulic (where the piston is activated via hydraulic fluid in a sealed hose, like the brakes on your car).

• Mechanical discs: These are cheaper than hydraulic disc brakes and, to v-brake users, their simple steel cable operation can appear less daunting than hydraulics when it comes to repair and maintenance. While good mechanical disc brakes are on the market, they are genrally outperformed by hydraulic disc brakes.

• Hydraulic disc brakes: These have brake hoses filled with incompressible brake fluid, so any movement at the lever is transferred immediately to the pistons. This means not only more power but more control when compared to open cable systems which can stretch and become clogged with grit and water.

Disc brake aficionados looking to upgrade to a better set of stoppers are spoilt for choice of aftermarket options. Most major manufacturers have radically overhauled their brake offerings in recent years, meaning top-end lightweight brake systems now offer the braking force that was once the sole preserve of heavyweight units. The best of these hydraulic disc brakes give most riders more than enough for their needs while shaving considerable weight.

Fitting Basics for Disc Brakes

Many modern disc brake sets come pre-bled, so you only need to bolt them on and bed them in.

However, if your hoses need to be cut down to fit your frame, or if you buy a set that needs to be assembled, they will also have to be bled – meaning any air bubbles trapped in the system will need to be let out, or the brake system will feel ‘spongy’ in use. The procedure for assembling and/or bleeding brakes will vary according to every manufacturer and brake system, so pay close attention to the instructions supplied with your new brakes, and take your time. Bleeding isn’t difficult, but it does take patience and care. Always enlist an experienced professional if you have any doubts.

Rim Brakes

Although hydraulic disc brakes are now used on the majority of bikes some riders still prefer the low weight and user-friendliness of non-disc or rim brakes (so-called because they use the rim of the wheel as a braking surface), which are also common on budget-friendly bikes such as the Cannondale CAAD Optimo 2.

Types of Rim Brakes

There are two main types of rim brakes – caliper brakes and cantilever brakes.

Bikes that use cantilever brakes use a specific type called v-brakes. These consist of individual brake arms mounted via two brake bosses, with each arm of the brake attached to a boss on each seatstay or fork leg.

Many entry-level or lower-spec road bikes, including road racing bikes, TT and tri bikes use a type of rim brake called caliper brakes. These use brake arms that reach downwards from above the tyre, with the entire brake unit attached to the frame or forks via a central pivot bolt positioned above the wheel. Pulling on the cable pivots both arms inwards, bringing the brake pad into contact with the rim. When adjusted correctly, both pads will hit the rim simultaneously.

Caliper brakes have the advantage of being compact, light and easily adjustable. However, their braking power is eclipsed by hydraulic disc brakes, which also have the advantage of using separate braking surfaces positioned away from the wet and grit of the road.

More and more road models now use hydraulic discs, with manufacturers racing to refine hydraulic disc brake designs to suit road bikes and road brake/gear lever combos.

Which rim brakes for a road bike should I buy?

As with v-brakes, caliper brakes for road bikes are functionally very similar across brands and price points – paying more will get you a lighter brake with sharper performance, but even the most budget calipers will work the same way as the most expensive.

Caliper brakes for road bikes can either be single-pivot, where both arms pivot at a single point (the centre bolt), or dual-pivot, where one arm pivots at the centre and the other at the side (the second pivot attached to the other arm).

NOTE: Most caliper brakes are used with the combined brake and gear lever units found on modern road bikes. Separate brake levers are available but cantilever brake levers (e.g. v-brake levers) are not compatible with calipers as they require a different amount of cable to be pulled to work properly.

Disc Brake Upgrades for Road Bikes

The vast majority of new road bikes available at Sigma Sports come with disc or hydraulic disc brakes, but if you are considering a disc brake upgrade for your current road bike, be sure to check compatibility. As with MTBs, disc brakes for road bikes will require mounts on the frame and forks for the brake calipers, and bolt holes on the wheel hubs for the disc rotor.

Fewer older road bikes will be ‘disc-ready’ as standard and it may be an expensive upgrade (also, for hydraulic discs you will need new brake/gear levers, or a cable-actuated widget called a disc brake converter which allows you to run hydraulic hoses to conventional road levers).

Road bike brakes:

Caliper brake pads – cartridge v non-cartridge

If you’re not happy with the performance of your road bike caliper brakes, you might want to check the type of brake pads you are running. Stock pads on entry-level models are often hard and cheap, but better-quality aftermarket options are capable of vastly improving your braking power.

When upgrading brake pads look for a rubber compound that suits the conditions you ride in (wet, dry or all-round compounds are available). Also, two-piece ‘cartridge’-type pads –which consist of a rubber block that slides into a metal cartridge – generally outperform the ‘all-in-one’ type pads that may be fitted as standard on low- to mid-end bikes.

A brake pad upgrade could be a cheap and effective way to get the most out of your bike’s brakes.

Long-drop brakes

An important factor to consider when choosing caliper brakes for a winter trainer or touring bike is the amount of ‘drop’ they have – i.e. the length of the brake arms. Because bikes designed for touring, winter training and commuting offer enough clearance to accommodate larger tyres (28mm and up) you are going to need to ensure that the brake arms are long enough to get around the tyres and reach the rim, and can also be used with mudguards. Look for ‘long-drop’ or ‘deep-drop’ brakes rather than ‘standard drop’ and you should be good to go.

Gravel Bike and CX Brakes

Disc brakes are widely available on gravel and cyclocross bikes, but these bikes traditionally used cantilever brakes and even more specifically centre-pull cantilevers. These offer a combination of braking power, clearance (for mud and wider tyres) and compatibility with road levers making them a popular choice for CX racers.

Gravel and cyclo-cross brakes: in-depth

Centre-pull cantilever brakes are similar to MTB-style v-brakes in that they consist of two separate brake arms mounted on either side of the rim, via bosses on the fork (front) or seatstays (rear), connected to the brake lever via a cable. Pulling on the brake lever tightens the cable and draws the brake arms in towards the wheel, where the brake pad makes contact with the rim and slows the bike. When the brake lever is released, springs in the brake arm return them to their original position.

Which cyclo-cross brake should I buy?

Previously banned in CX racing under UCI rules, disc brakes for cyclocross have the advantage of using a separate braking surface positioned away from the muck and wet of the race course, with the benefits of improved braking performance and longer rim life.

However, if you are considering a disc brake upgrade for your cyclo-cross bike, be sure to check compatibility. As with MTBs, disc brakes for CX bikes will require mounts on the frame and forks for the brake callipers, and bolt holes on the wheel hubs for the disc rotor.

Mountain Bike Brakes

For full-on DH and Enduro mountain bikes, you can choose to boost your stopping not only by increasing your rotor size but also by investing in some heavy-duty multi-piston caliper systems. Instead of the two opposing pistons (‘pots’) present in most calipers, four- or even six-pot units can not only provide ultimate stopping power but also minimise the risk of your brakes losing power when they overheat under heavy and sustained use, causing the brake fluid to boil in the system (‘brake fade’).

Eliminating brake fade by improving heat dissipation is also the reasoning behind a new generation of vented and/or ‘floating’ rotors. The former consists of two parallel discs with a space in between, allowing cooling air to flow between the two sides of the braking surface. At the same time, floating rotors feature a stainless steel outer braking surface bolted to an aluminium central carrier, or ‘spider’. This two-part rotor stays cooler for longer and is lighter than an all-steel equivalent.

Other MTB brake upgrade options include braided hoses, which are designed to increase brake power by reducing energy loss through hose expansion.

More investment also means more adjustability - most top-end brakes now allow riders to tune their brake pad bite point and brake lever reach to suit their preference, adjust the angle of their brake hoses, and more.

MTB disc brakes: in-depth

Compatibility – frame and forks: The first thing to consider if upgrading to disc brakes is whether your frame, forks and wheels can take them. Nowadays most MTB frames and forks will have disc mounts as standard, but you will want to double check if you are kitting out older models.

Something else to consider is facing your frame’s brake mounts – removing any excess paint or metal left over from the manufacturing process to make sure the mounts are perfectly parallel. This can ensure that calipers are mounted perfectly for optimum performance, but it’s generally a job for a professional workshop.

NOTE: Before buying your brakes make sure to check which mounts are present on your frame and forks, and choose your stoppers accordingly.

Compatibility – wheels: Your wheels will also need to be disc-ready in order to attach the rotors. If they do not have hubs with mounts to attach a rotor, you are looking at rebuilding with disc hubs, or as may be more practical, a new set of wheels.

Rotors – width: Each caliper is designed to take a specific size of rotor, in terms of both diameter and thickness. Whereas you can generally vary the diameter size of the rotors with the use of adaptors, different manufacturers and brake models will use marginally thicker or thinner rotors. Although the differences in thickness are tiny, you’re best to avoid mixing and matching rotors with calipers if you want to avoid problems with brake rub (where the pad is constantly touching the rotor surface, therefore wearing it prematurely as well as creating an annoying noise while cycling)

Rotors – diameter: An essential consideration is rotor diameter. Broadly speaking, the bigger the rotor you are using, the more braking power available.

The bigger the disc, the more braking surface is available per revolution of the wheel and the more leverage your brakes are able to exert on it. The most common rotor sizes are 160, 180 and 203mm. When choosing, you must take into consideration the type of bike you are riding and the type of riding that you do. Most XC and trail riders will find 160mm rotors offer more than enough stopping power for their needs; gravity-oriented AM or Enduro riders will find benefit in stepping up to 180mm.