Advice: all you need to know about brakes

Brakes are brilliant – until they’re not. A squeeze of the front brake lever in conjunction with a stomp on the rear brake pedal and your braking system will do a remarkable job of bringing your motorcycle to a quick and effective stop. You’ve probably worked out that braking systems are all about friction.

Whether your bike uses a cable-operated drum brake, a hydraulically operated disc brake or a mixture of both, friction of a fibrous material against a hub or disc of a rotating wheel is what is slowing you down. The capability of the braking system on any bikes is generally well matched to suit both the machine’s performance capabilities as well as its retail price.

Most modern motorcycles will employ disc brakes on both the front and rear wheels. Occasionally you’ll come across a modern machine which opts for a drum-style rear brake, but since most of the stopping performance comes from the front-end, it shouldn’t be a deal breaker if your dream bike runs a drum brake at the rear.

Housed within the wheel hub and actuated by a cable, two half-circle shaped ‘shoes’ are pushed outwards and against the rotating hub when the brake is applied to cause the friction required to slow the motorcycle.

A brake disc on the other hand, runs between a caliper which houses opposing brake pads which bite the disc when the brake is applied to cause the necessary friction. The most significant difference, however, is in its actuation.

Instead of relying a cable which can stretch and break (the latter probably when you’re asking the most from it), a disc brake is operated by hydraulic fluid. By squeezing the lever or pushing on the brake pedal, you’re forcing brake fluid down through the brake lines which push against pistons inside the caliper and forces the pad against the disc.

Like any often used component on your motorcycle, brakes pads (and shoes) will wear out. Most brake pads will have a groove cast into the surface which acts as a wear indicator. Once the groove is getting close to disappearing, it’s time to start thinking about replacing your pads – torchlight directed into the caliper will generally help you see if the pads are worn.

And like tyres, the replaceable items come in a vast array of compounds and materials to suit the type of riding you’re doing (more on that later). Pads will wear at a faster rate than discs, but it’s a good idea to keep an eye on disc wear on older bikes. Discs, sometimes called rotors, can be machined if they form ridges or lips on their edges over time, but each manufacturer will specify a minimum thickness. Once this is reached, they’ll need to be replaced.

The brake fluid itself will need to be topped up occasionally, and flushed and changed completely in accordance with your bike’s maintenance schedule. Housed in a master cylinder either mounted on the handlebar for a front brake, or near the footpeg for a rear brake, the level can be checked quickly via high- and low-level markings on the reservoir. If you’re topping up your own brake fluid, only use the brake fluid type as specified on the lid of the reservoir (or higher). Brake fluid id also extremely corrosive, so it’s very important not to spill it on your bike’s paint.

Unless you’re racing or attending the odd track day, chances are you’ll be satisfied with the performance of your braking system as it comes from the factory. But there’s a few small things you can do which can significantly enhance the braking performance of your motorcycle.

The first thing is changing the compound of the brake pads. The choices include an organic compound pad (generally made up of fibres like kevlar and carbon and all held together with resin), sintered pad (which made up of metal particles which are bonded together at a high temperature and under extreme pressure), and he less common ceramic, which uses copper and – as the name suggests – ceramic.

Organic pads are generally the least expensive and will wear the quickest, while fully sintered pads produce stronger braking performance and will last longer. The drawback is they’ll cost you a bit more up front, but they’ll also wear your disc at a faster rate. If you’re not doing a lot of track time or fast weekend scratching, perhaps a semi-sintered pad is a good place to start, which is a mix of organic and sintered fibres.

While hydraulic systems have the benefit over a cable of not stretching or breaking, as a bike ages the rubber hoses in which the fluid is pushed down to the brake caliper can soften. This means they can expand and absorb some of your braking force when you apply the brakes. So another small upgrade to your braking system which will return significant results is to replace the rubber hoses with braided steel lines, this means the fluid has nowhere else to go except to put pressure on the pistons which push against the pads. You’re going to get a much more positive feel at the lever (or the pedal), too, with a more positive action inside your caliper.

Many modern braking systems are complemented by a suite of electronics. In fact, these days in order to comply with Euro4 regulations, any motorcycle sold in Europe which is 250cc or above is required to have an electronic anti-lock braking system (ABS).

Like anything else, ABS ranges from relatively rudimentary systems through to incredibly complex and intelligent systems. At a more basic level, a wheel-speed sensor is fitted to both the front and rear wheels and, if the system senses that the front and rear wheel speeds are different, ie, if one of the wheel locks, the electronics will intervene and release the brake. It all happens within a milliseconds and the brake is reapplied probably before many of us have probably even realised what is going on.

A more complex system, generally found on higher-spec and higher-priced machines, will offer far more intelligent goings on complete with lean-angle sensitivity. Not only are these systems much more effective in that they’re running diagnostics many, many more times per second, but it’s also garnering information about your roll, yaw and pitch – or your rate of acceleration and braking matched to your lean angle. It’s then marrying this info with your throttle and brake inputs and making some extremely clever calculations about how much braking intervention it will apply in order to give you the best and safest outcome.

Some machines will also offer a linked or combined braking system, which means if you apply only the front or rear brakes, then the machine will automatically apply partial or full pressure of the other end depending on the type of bike you’re riding or your braking inputs.

This article was originally published on August 31, 2018.