Road disc brakes: a mechanic’s view

Disc brakes on road bikes. I haven’t seen a technical innovation that’s caused as much controversy since – well, since Shimano invented a little thing called Di2. Sure, there’s a lot of hand-wringing about their place in the professional peloton, but in terms of the rest of us riding around, are they worth the extra expense?

Here’s a no-nonsense look at the pros and cons of road disc brakes, and whether you need them on your bike.

They work better than caliper brakes in almost every way
From a functional perspective, the marketing hype is all true. Road discs, when they’re properly adjusted, are the mutt’s nuts when it comes to every aspect of braking.

It’s not just about getting more stopping power under you, however. Discs don’t actually give you that much more stopping power than a decent caliper brake. However, the difference is all at the lever. You’ve got much more control over the amount of braking force you use, and it requires very little power from your fingers to apply that force. Plus, it feels buttery, buttery smooth – no cable friction here – and you get very similar performance whether you’re riding in the wet or the dry.

Sure, you can still skid out or lock up just as easily, and the amount of grip from your tyres is critical, but disc brakes make much more sense in the wet.

Maintenance
Of course, all of the above depends on those brakes being properly adjusted and in flawless working order. The generation of brakes that are specced on 2015 and 2016 model year bikes are practically issue-free.

From a workshop point of view, road hydraulics need very little maintenance, aside from an occasional bleed and pad replacement. There are a couple of quirks.

First, some riders have complained about their pads constantly rubbing on the rotors. Almost down to a man, this is because of the quick release lever not being done up tight enough and not holding the rotor in place securely enough.This will become less of an issue as we see more road bikes equipped with the through-axles rather than quick-release skewers.

To prevent this, you need to do up the quick-release skewers a fair bit tighter than you may be used to. This is all well and good for us mechanics, with our fingers constructed of sprung steel, but this can be challenging for mere mortals. All I can say is, get working on your finger exercises.

Complaint number two is squealing brakes. This is a fact of life with disc brakes, and every mountain biker for the past 20 years has learned to love the siren song of the rotor. The chief culprit for this is dirty and/or contaminated pads. The only way to prevent this is to clean your brakes. Get some disc brake cleaner, get a clean rag – and I mean clean, not covered in chain lube or yesterday’s lunch – and wipe over your rotors when you get home from a ride, especially if it’s a wet one. You will save a lot of money on pads in the long run.

Here are some more useful maintenance tips for road discs.

Racing wheels
If you enjoy lining up at the local crit or road race on a Sunday morning, you’d better resign yourself to the fact you won’t be doing it on your shiny new road disc bike. Either that, or take up cyclo-cross.

In addition, a disc-equipped road bike may not be the choice for you if you prefer to have a set of wheels for every occasion. Not every frame will be compatible with every manufacturer’s wheelset, especially as hub, axle and mounting standards settle down. If you do want to run multiple wheels, be prepared to take the time to do the research on compatibility (and be braced for some pain), or hold off a few more years until the technology has bedded down.

Yes or no?
From a functionality and maintenance point of view, disc brakes are a huge leap forward from the caliper brakes we’re used to on road bikes. Seriously, the difference when riding is like the difference between alloy and carbon frames, or between mechanical and electronic gear shifting. It’s hard to go back to calipers once you’ve got used to the control that discs give you, especially in wet conditions.

However, it depends on you and the kind of riding you do as to whether you should rush out and buy one today. If you’re looking for a bike for the morning bunchie, to ride in gran fondos and to commute on, you absolutely should consider it as an option. However, if you’re a weight-weenie racer or like to keep your options open on wheel choice, then perhaps hold off for a couple more years.

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