After the frame, a quality set of wheels is probably the most important part of your touring bike. Invest in a good set and you can happily embark across Mongolia or blaze a trail through Europe without so much as a broken spoke, and barely a twist of a spoke key. A set of touring hoops can also add versatility to your existing bike. And seeing as they're built for regular, day-in-day-out use, they cross over well to the demands of commuting.
What to look for
Most touring rims use a thicker box section extrusion that's designed for regular use and mixed conditions.
Look out for double eyelets, as these help spread the load across the rim. Thick sidewalls should mean longer life, though different rims wear at different rates depending on the aluminium alloy used. Smooth join-welded seams are preferred. Pick a model that suits your uses. Narrower rims seat more slender tyres (eg 25/28mm/1.125in rubber for lighter touring), while wider ones are recommended for tyres you would use on longer, fully laden and often unpaved tours (e.g. 40mm/2in). Have the rims drilled for both Presta and Schrader valves if you're not sure what you'll be able to find locally.
If you're planning to ride in an isolated part of the world a stronger, wider rim is recommended, though this will inevitably come at a cost to weight. If you're riding paved surfaces with light loads, then a lighter combination will be more enjoyable. But don't expect any touring wheel to feel too sprightly. The increase in rotational mass of a heavier rim and touring tyre will be far more noticeable than a few hundred grams in the weight of a frame. A second, lighter set of wheels is recommended if you want to pep up the performance for day rides.
Building touring wheels
The majority of wheelbuilders stick to a traditional three-cross spoke pattern for touring wheels, as this means the spokes are at a greater tangential angle to the hub, spreading the load across the flange. While 36 holes are generally recommended, lighter and unladen riders may get away with 32 (the weight saving is minimal but they're easier to source) and tandem riders may prefer up to 48 spokes and a four-cross pattern to cope with the extra weight and power.
Theories abound as to what makes the perfect wheel. The rear bears the brunt of the work and for the strongest and most versatile build, we'd recommend a combination of spokes, such as single-butted (13/14) on the drive side and double-butted (e.g. 14/16/14) on the left. This helps counteract the dishing of a cassette by equalising tension, so there's less chance of a spoke rattling loose or snapping - and we'd recommend it for a front disc wheel too. This said, there are plenty of tourers who use double-butted spokes all around without any problems. Butted spokes offer more resilience and flex in the wheel, allowing less stress on the hub and rims, and even a little more comfort for long days in the saddle. But they're more expensive than plain gauge.
Most wheelbuilders aim to build their wheels to within one or two mm of true in any direction; much closer than this isn't necessary due to imperfections in the seating of most tyres. If you want to build your own wheels and learn more try Josh Brandt's classic book, The Bicycle Wheel.
On tour, make sure you have the right length spokes for the wheels you're running, and label them up accordingly. Taping them to the chainstay of your frame keeps them out of harm's way. Check your rim tape regularly and ensure it's wide enough - we like cotton tape. Keep an eye out for splitting around the nipples and wear along the rim, though wear line indicators are common nowadays. If you're not sure, run your thumb and forefinger down each side of the rim's brake surface; if it's concave it needs changing. Alternatively, set the pads close to the rim with the tyre flat. Pump it up to normal pressure and see if the rim has expanded and the brakes rub. Check too that your pads are clean, as debris can cause damage.
For commuting, we recommend removing the tape once a year and spraying the nipples with WD40 to guard against corrosion from salted roads. You can also spray the thread of the spoke by turning it clockwise then anti clockwise. A drop of Locktite will help prevent spokes from rattling loose - though if your wheels are built correctly, they should be okay.
When building a wheel for touring, make sure you stress it a few times so it stays true when you ride it; squeeze a pair of spokes, or lay it on the ground and press on the rim. If you need to true a wheel on tour, use small turns, and try to only tighten spokes. For removing the cassette use Spa Cycles Stein Mini Lock Ring tool (£15) - just make sure your cassette isn't done up too tight. Look after your hubs with a yearly strip and clean, and they should do you proud.
It's no surprise that Shimano hubs feature on most touring wheels, thanks to strong axles, quality seals and competitive pricing - and they can be found in most parts of the world. They're easily serviced with cup and cone bearings - the front and rear axles are non-specific too. Wider Mtb hubs are laterally stronger, which is ideal for touring. For 135OLN, we'd recommend Deore or XT, depending on budget and use.
If you have 130OLN dropouts, Shimano 105 and Ultegra are similar in quality with the same seals, though they lack the extra rubber sleeve. Alternatively, ask your wheelbuilder to cut down the axle of a mountain bike hub by 5mm. Sealed bearing hubs (e.g Hope Monos) are preferred by some tourers for their simplicity and smoothness. However, specialist tools, particular to the manufacturer, are often required to replace them, making them less suited to long and remote rides. Always use quality skewers and nothing too lightweight.
26in v 700c
While there's little difference in rolling resistance given the right tyres, the perennial debate between 26in and 700c wheels for touring wages on.
Frame size, toe overlap, road conditions, destination and aesthetics will all influence your choice. Both are now complemented by a wide range of tyre treads and maximum pressures. In fact, both have their advantages and disadvantages. 26in wheels are marginally stronger due to their slightly smaller size.
Most importantly, they're easier to source within popular touring destinations in developing countries, notably Asia and Africa - even if the quality leaves something to be desired. 700c wheels seem to roll a little better, particularly over bumps, but take a bit more effort to kick up to speed - they're readily found in the States and Europe. Of course, certain folders, recumbents and trikes use 20in wheels: these will be stronger still but the rims will wear that bit faster. Quality spares are less usual - a spare tyre or an international courier may be the order of the day.