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BIKE BRAKES 101
A bicycle needs two independent brakes to be safe on the road. In Germany and many other countries it’s even a legal requirement for bicycles used on public roads (see e.g. StVZO regulation in Germany). Apart from that, the importance of properly functioning brakes should be obvious to anyone: They are the key to a safe ride on your bicycle. However, bicycle brakes are not only used to slow down a bike, but they also contribute to an efficient ride. Proper and well modulated braking increases riding enjoyment and can determine victory or defeat for competitive riders.
TYPES OF BICYCLE BRAKES
The principle of any vehicle brake is simple: They use friction to slow down and stop a moving vehicle. On a bicycle, the bicycle brakes are used to reduce speed. There are two main types of bicycle brakes:
- Rim brakes use brake pads that are pressed to the rim. The calliper is controlled via a brake lever on the handlebar.
- Hub brakes use a brake mechanism located inside or close to the wheel’s hub. Hub bike brakes are actuated with a brake lever or by rotating the pedals in reverse. Disc brakes are a particularly common type of hub brakes.
RIM BRAKES: THE DIFFERENCE BETWEEN CALLIPER AND CANTILEVER BRAKES
Rim brakes have brake pads that press against the wheel’s rim once the brake lever is activated. There are many different types of rim brakes with different designs and mounting types. The two most important types of rim brakes are calliper and cantilever brakes. A characteristic feature of calliper brakes (also known as side-pull or centre-pull calliper brakes) is that they are connected to the brake bridge or fork crown using a single bolt – this way, they function as a single unit. As the name implies, single-pivot calliper brakes consist of two brake arms that pivot from a central bolt.
Cantilever brakes, on the other hand, consist of two separate brake arms mounted either side of the rim. The arms are attached to the frame or fork using special fittings called “braze-ons”. If you want to buy a cantilever brake, you should first check whether it can be fitted to your bike. There are four different types of cantilever brakes. However, the most common types are traditional centre-pull brakes and V-brakes. V-brakes require special brake levers. U-brakes that were popular in the 1980s no longer play a role today.
- Shimano Alivio BR-T4000
- Shimano Deore BR-T610
- Shimano Deore XT BR-T780
MAGURA HS, THE HYDRAULIC RIM BRAKE FOR FREQUENT RIDERS
Hydraulic rim brakes such as the Magura HS33 are less sensitive and stronger than classic calliper and cantilever brakes, because here, the force is not transferred mechanically but via a fluid. Therefore, these types of bicycle brakes score with enormous braking power and particularly good braking power modulation. Hydraulic brakes are particularly used on e-bikes, as mechanical brakes would quickly reach their limit here: With a permissible total weight of up to 140 kilograms, e-bikes are simply too heavy.
DISC BRAKES: BICYCLE BRAKES FOR ALL WEATHER CONDITIONS
Disc brakes are mainly used on mountain bikes, cyclocross bikes and electric bikes. They stand out for a high, less weather-dependent braking performance and very good modulation. Lever force is transferred to the brake rotor – and not to the rim flange as with rim brakes. This not only protects the rim, but also allows manufacturers to develop wheels, that are lighter and stiffer. Disc-specific rims such as the DT Swiss 545D or the Spike Race28 Evo can therefore only be used with disc brakes.
MECHANICAL AND HYDRAULIC BICYCLE BRAKES
A disc brake system consists of a brake lever, a brake calliper, a brake disc and a brake line – or cable. This is exactly where a distinction must be made between hydraulic and mechanical systems. Mechanical disc brakes use a Bowden cable to actuate the pistons that then push the brake pads against the rotor. In contrast, hydraulic systems use a special DOT brake fluid or mineral oil instead of a cable, depending on the model you choose. Hydraulic disc brakes are extremely reliable and smooth-running – provided they are professionally installed and regularly bled. They also provide the perfect bite point on longer descents.
BRAKE CALLIPER: DISC BRAKE MOUNTING STANDARDS – AN OVERVIEW
When choosing a brake calliper, you should pay attention to the mounting standard or the brake calliper mount. It’s not always possible to combine the different standards using adapters. Depending on the bicycle frame or fork you are using, you can find the following mounting types: post mount, flat mount and IS2000. While the mounting bolts run parallel to the wheel on post mount systems (the bolts screw in from the top or from diagonally in front), the bolts of IS2000 mount types run parallel to the axle, i.e. offset by 90 degrees. The flat mount system is similar in design to the post mount standard. This modern system developed for road bikes impresses with its extremely flat design and a closer bolt spacing, which allows for the use of disc brakes even when space is limited.
DISC ROTORS FOR BIKE BRAKES: MORE THAN JUST A ROUND PIECE OF METAL
High braking forces, extreme frictional heat and changes in temperature place high demands on disc rotors. The braking surface is usually made of stainless steel, recessed slots and channels allow for better heat dissipation. Depending on the hub you are using, the brake disc comes with a centre lock or a six-bolt mount. The Centerlock standard can be clearly identified by the spline and the large lock ring.
Good to know: When using a special adapter (e.g. Shimano SM-RT-AD05 Centre Lock adapter), you can also mount 6-bolt brake rotors on Center Lock hubs if required.
Most brake discs are made of stainless steel. However, Center Lock brake discs usually not come in one piece, but have an additional separate carrier. This so-called spider is riveted to the disc brake surface.
GETTING THE RIGHT ROTOR DIAMETER
Rotors come in different diameters, depending on the category of bike you’re riding. The right disc diameter basically depends on the required braking power. The maximum rotor diameter is specified by the frame or fork manufacturers. Never exceed the maximum rotor diameter, as this may cause irreparable damage to the frame or fork due to the additional load.
PADS FOR BIKE BRAKES: FOR EVERY REQUIREMENT
No matter whether you’re using rim or disc brakes: The braking power can be optimised depending on the conditions you ride through. Brake pads with an adapted rubber compound give rim brakes more braking power in wet conditions. There are also solutions that are optimised for good braking power modulation, durability and/or improved braking in dry conditions. However, you should always make sure to choose the right brake pad for your rim.
There’s a wide range of different brake pads available for disc brakes. You basically have the choice between organic and sintered pads. Organic brake pads consist of more resin and fibreglass and impress with more initial bite and low noise. However, they are quite sensitive to temperature. Sintered pads, on the other hand, can withstand significantly higher temperatures which makes them particularly suitable for demanding conditions or long descents. The added metal elements in sintered pads increase their service life, but also tend to squeak when braking. Semi-metallic brake pads such as the ROSE disc pads offer a good compromise, as they combine optimal braking power with high durability and low noise. Depending on the manufacturer and bicycle brake model, semi-metallic pads consist of between 30% and 65% metal.
BRAKE/SHIFT LEVERS: ERGONOMICS FOR MORE RIDING COMFORT
Without a brake lever a bicycle brake wouldn’t work – whether mechanical or hydraulic, rim or disc brakes. Ergonomic brake levers guarantee optimal grip and thus improved sensitivity when braking. On bicycles with straight handlebars, such as mountain bikes or city bikes, the brake and shift levers are usually separate components.
The situation is different, however, on road bikes, cyclocross bikes or gravel bikes with so-called drop bars. These types of handlebars use special brake/shift lever combinations with the shifter integrated into the brake lever. Yet, the manufacturers have different solutions for the control of the integrated shift lever.
WHICH BIKE BRAKE IS BETTER: DISC OR RIM BRAKE?
Generally speaking: Disc brakes use more modern technology and are becoming increasingly popular. Nevertheless, many cyclists still use rim brakes. This is mainly due to the low weight, the low price and the proven technology of this bicycle brake. However, since the braking force is applied to the rim flange by rubber pads, there are also disadvantages: In contrast to disc brakes, the braking power of rim brakes decreases in wet conditions. Special brake pads with an optimised rubber compound can help optimise braking performance in wet weather. Another disadvantage is the high wear and – one aspect that is a burden on the purse of frequent riders – mechanical abrasion of the rim through friction. Special rims with a ceramic coating last significantly longer, but require appropriate pads.
So it's not really possible to say whether disc or rim brakes are better. Which brake type is better for you depends on your requirements and your style of riding. Disc brakes are currently taking over in almost every sector of cycling. Mountain bikes, for example, are fitted with disc brakes as standard, hybrid and city bikes use both types and even in the road bike sector, disc brakes are becoming increasingly popular.