Brakes.

The main types of brakes on bikes are side-pull, V-brakes (left picture), cantilevers (right picture) and disc brakes.

For bikes with tyres around 35C and with mudguards, side-pull  are not an option. The central mounting point for them is so far away from the rims that the calipers in that length would be too weak.

Cantilever brakes have been a long-term favourite on touring bikes. Shimano for many years has made a brake called the R550 which has been the benchmark. But in 2013 it was discontinued and replaced by a new lighter model intended only for cyclocross racing. We tested it and it is not robust enough for loaded touring. Basically, cantilevers were popular because they were the best option available for a long time.

V-brakes have become the most dominant brake type on bikes with mid-sized tyres and flat handlebars. V-brakes are light and easy to adjust. But for a long time there was an incompatibility between drop-handlebar brake levers and V-brakes. The long arms of V-brakes required more brake cable travel and the dropbar levers had short travel. Hence we could only use V-brakes with trekking bars.

In 2013 Shimano released new 9speed STI levers that were compatible with new shorter V-brakes. So, since the start of 2013, we have had the option of combining drop bars with V-brakes.

Finally there are disc brakes. There are mechanical discs which use a brake cable. And there are hydraulic discs where there is an oil filled casing between the lever and the caliper. The lever needs an oil reservoir. Just in the last year Shimano and SRAM have developed STI dropbar levers (combines brake and gear levers) with this functionality. But they are not 9 speed levers and they are very lightweight and intended just for cyclocross racing. In summary, cable actuated disc brakes now are an option on drop bar touring bikes. But hydraulic disc brakes are not.

On 2012 and earlier stock of touring bikes you can still get Shimano R-550 cantilevers. Otherwise you will see more V-brakes and you will start to see disc brakes.

V-brakes and cantilever brakes both operate on the rims. They are called rim brakes. There are two important issues here. Firstly, the wheel needs to be kept true. Having 36 spokes, rather than the increasingly common 32, makes this easier. But, with the small amount of travel in brake levers, especially for shorter riders with small hands, the brake pads need to be set close to the rims. Any out-of-true in the rim can cause the brake pads to rub on the rim. This slows you down and is annoying.

Meanwhile, a wheel with a disc brake can have a buckle in the rim and you not need to do anything about it unless it is great enough to be rubbing on the mudguard/fender.  

The other issue with rim brakes is that they actually wear rims out, especially on front wheels where most braking force is applied.  Abrasive matter gets picked up and embedded in the brake blocks. This is at its worst in wet conditions. Occasional filing of the brake blocks to remove flakes of anodizing can reduce this wear, but the wearing still happens. It is a problem for bikes that are used a lot which includes bikes on long trips. The fact that many modern rims have a wear indicator line does nothing to solve the problem.

After a rim is worn it eventually folds out from the added pressure when you are pumping the tyre. You need a new rim when that happens and if you are in a remote place that will probably be difficult, or impossible, to find in your diameter and spoke hole number. So you wait whilst one is flown in. Or you catch a bus to a city to sort it out.

For decades we had to put up with these issues. But, when disc brakes were developed for mountain bikes, we figured we had to try them out on touring bikes.

When we first tested a front disc brake we immediately noticed it was stronger. On any bike the brake quality is important but on touring bikes where big loaded descents are common we want the best brakes available.

Rims are closer to the road than disc rotors are. In the wet there is more grunge on the rim more than on the disc rotor.   

Close-up of a rear rim that has done 14,000km, pumped to 80 psi. It is starting to bow out. Soon it will crack when the tyre is being inflated.

Disc brake pads, when retracted, ride closer to the braking surface than rim brake pads. This prevents build up of water or debris between the disc rotor and the pad. Holes in the rotors allow the escape of water. Well adjusted disc brakes also feel safer at high speeds, such as coming down mountains. They are easier on the hands and they can be modulated better.

Disc brakes apply greater twisting forces on hubs, spokes, nipples and rims. But, on long distance touring bikes none of those components are on the “lightweight margin”.  They are quite compatible with the disc system. Further, we are using a gauge of fork blade and a fork dropout which prevent the movement of the hub under heavy braking. It is essential that hub quick release skewers be kept tight.

It is also essential that the rotor ringlock be kept tight. There is a special tool (the same one as the cassette lockring tool)  and you should carry this when on a long trip. You can tell if the rotor is loose by holding the brake levers on hard and rocking the bike back and forth, feeling at the junction of the rotor and the hub for any movement. There should be none. Do not do this when the rotor is hot.

Both Avid and Shimano make centre lock disc rotors and it does not matter which one you use. 

Top of the class. Avid's  BB7 disc calipers are the same as the Shimano model in brake performance but are winners due to their easy adjustability.

Shimano tool for removing or tightening the disc rotor lockring. (Also for the cassette lockring.)

Stainless steel disc rotors do wear out but nothing like at the rate that aluminium rims wear out. And, if the disc pads are replaced before the pads wear down to metal, a rotor will last for many years. When you wear the pads right down and reach the metal-on-metal stage, the pads must be changed immediately. That means you should have spares with you when travelling. For Shimano calipers use BR-M965 metallic pads. For Avid BB7 the Avid Juicy/BB7 organic pads are fine although sintered (eg EBC gold) pads are better. The organics last about 5,000km on the front of a touring bike used in the city and on tours although off-road muddy MTB conditions do wear them faster. Sintered copper alloy brake pads last several times longer than organic pads in wet muddy conditions.

Disc rotors also can be bent, particularly during transportation. But it is not hard to avoid this. It is best to pack the front wheel with the rotor away from the frame to stop it being pushed against the frame. Have the wheel securely tied (tight zip ties) to the frame. See our packing advice. 

There are other dangers for disc rotors. Bike racks that you wheel the front of the bike into are one to be wary of.

If disc brakes are so good why not have them on the rear too?

The majority of braking occurs at the front and the rim-wear problem from rim brakes is greater on the front. So having a front disc brake on a touring bike achieves a lot by itself. We use a 70gm heavier rim on the rear wheel, doubling as a heavier load-bearing rim, so the rear wear aspect is substantially addressed.  

There is something appealing about having two different brake systems on a bike that is designed to be ridden around the world.

We have front brake pivots on the forks to mount the front light bracket. The front light bracket will still mount on these pivots if they are in use for cantilever or V-brakes. Rim brakes, such as on the rear of your bike, will fit onto these front pivots. We supply, with bikes that come with a rear cantilever brake, the small component needed to be installed in the headset that would allow the rear brakes to be moved to the front. (Front cantilever hanger). So, if you are in Outer Mongolia and wear out your disc pads, and lose your spares, by virtue of having two brake systems, you move the back brake to the front and carry on. You have no rear brakes but you can still ride.