Bike Braking Systems: Rim vs. Disc Brakes
For years, rim brakes were the most popular braking system. Using callipers with brake pads on the end of each arm, these are mounted at the front to the bike’s fork and at the back to the seat stays – when the brakes are engaged, usually activated by a cable that runs from the brake levers to the callipers, the pads squeeze against the turning rim, creating friction which slows the bike down.
While simple, light and cheap to replace, rim brakes' lack of complexity comes with a handful of disadvantages.
Firstly, the creation of friction on the rim results in production of heat, which can cause dangerous tyre blowouts when braking hard. It also wears down the rim which will eventually need replacing. Secondly, rim brakes are especially vulnerable to the elements, in that mud, grit and water can easily come off the wheel and coat the brake pads, reducing braking efficiency and requiring additional pressure on the brake levers to counteract it. Lastly, for riders who prefer to run multiple size of tyres on their bikes, rim brakes limit what the bike can accept, as the tyres must be narrower than the width between the calliper's arms. In the same way, if the bike experiences a jolt that snaps the tyres out of true, then the rim brakes won’t be alignment and won’t work properly.
An alternative to rim brakes exists in disc brakes. Initially popular amongst mountain bikers, for whom efficient and quick braking is crucial, disc brakes have over the past few years been increasingly taken up by the road bike community. They work via the mounting of rotors (discs) to the bike's hubs which then rotate with the wheels as they turn – taking the role of the rim, the callipers, which are mounted at the front on the fork and at the back by the seat or chain-stays, grip the rotating rotor when the brakes are engaged. Disc brakes are often actuated by a hydraulic system rather than cables, which means the hydraulic fluid in the brake lines pressurizes when the brakes are engaged, causing a piston in the calliper to push the brake pads against the rotor.
There are many advantages of having disc brakes. Firstly, they offer more stopping power than rim brakes as there is a larger surface area on which the pads act, which means that less pressure is needed to successfully engage the brakes. Secondly, disc brakes are protected from the road surface and are less likely to get wet or muddy. Neither does their mechanism result in the rims heating up so there is little chance of a tyre blowout. You can also run multiple tyre sizes on them and the material the rotors are made of usually last longer than rims.
There are a few downsides of disc brakes, however, including their complexity, price and weight. Rim brakes are also slightly easier on the spokes. Nevertheless, disc brakes represent the best in bike braking technology. That is why the Abington and Rosemont are fitted as standard with disc brakes.
With an innovative disc brake project currently on our product development agenda – be sure to follow ARCC Bikes for exciting, future announcements.