Everything you need to know about disc brakes

With the glacier that is the UCI inching ever-so slowly towards modernity, road disc brakes are making their way into the pro peloton for 2016. There is also an increase in the number of disc-only or disc compatible bikes coming onto the market. So road discs seem to be here to stay. But what is all the fuss about?

What are disc brakes?

Disc brakes are borrowed from mountain biking where they replaced rim brakes on just about every bike going. When you’re hurtling down a technical course with a 12kg bike at 30mph, rim brakes just don’t cut it.

By using motorcycle technology and placing a metal disc in the centre of the wheel and a brake calliper on the fork and seat stay, a much more effective braking mechanism has a much better chance of stopping you. As disc rotors and callipers became lighter, they also became relevant to roadies.

There are two main types of disc brake, mechanical and hydraulic. The first uses a brake cable to close the calliper while the hydraulic versions use brake fluid, exactly like a motorcycle. Of the two, hydraulic is the preferred option. It allows much more braking force to be applied with less pressure on the brake lever and is smoother in operation too.

A third type, cable actuated are a combination of the two but don’t seem to be widely used as yet.

Disc brake modulation

You will hear the term ‘modulation’ used a lot in terms of hydraulic disc brakes. This is the movement of the lever and consequently the calliper against the disc rotor. Hydraulic allows for a very smooth movement with less pressure, which equals a more predictable and therefore, safer braking action.

The advantages of disc brakes over rim brakes

Rim brakes have served us well and continue to do so yet we know they have downsides. Ask any rider who has carbon rims about their braking experiences and you will quickly see why discs are becoming so popular.

Brits will soon take road disc brakes to their hearts as they cope with poor conditions much better than rim brakes. Soon, those days of pulling frantically on the brake while nothing happens until the rim dries will be a thing of the past! Disc brakes do not suffer through wet, mud, snow or ice and they only fade under exceptional heat loads rather than the modest loads rim brakes can cope with.

As you don’t have to worry about expensive rims when applying disc brakes, you can pull them as hard as you need to in order to stop. Physics takes over and as long as you distribute your weight effectively, you can stop much, much faster.

Wheel manufacturers like them too as they no longer have to worry about braking force and creating the metal rim track. They also have more freedom in terms of wheel shape and materials too.

The disadvantages of road disc brakes

There are two main disadvantages of road disc brakes, weight and cost. While new products are reducing weight all the time, in an sport where we spend hundreds of pounds to shed 50 grams, adding another 200 grams is a hard pill to swallow. However, for better stopping power in all conditions, I think it’s a worthy compromise.

Cost is a factor in everything a cyclist does. At the moment, it is still early days so road disc brakes are still at a premium, as are the bikes and frames that are compatible with them. As more manufacturers get on board with discs, we will see prices reduce. Giant is leading the way with a whole range of dis equipped bikes and others will follow.

If you elect for hydraulic brakes, there is a maintenance need there too which might put you off. Rather than tighten a cable and change some blocks, hydraulic brakes need bleeding just like a motorcycle. While it is very easy to do, I have done it plenty of times on my mountain bike, it will be a barrier to entry for some.

I think the future of road cycling has a place for road disc brakes. Whether they completely replace rim brakes or not I don’t know. I do know that were I not still in love with my TMR02, I would be shopping for a disc-equipped bike right now. Although n+1 does offer a little wiggle room…


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