The debate over the best wheel size for cycle touring frustrates me. I see so many people who have gone out and bought the wrong bike for the trip they are doing so I hope this blog helps. Yes there are a lot of options out there and manufacturers aren’t helping by offering new wheels and new marketing opportunities every year. Granted it isn’t as simple as it once was because new cycling niches developed such as fat bikes and gravel bikes which are great fun. However for this analysis I should say my bias is towards efficiency, covering the miles on roads and rougher tracks as easily as possibly so I can get somewhere new and explore more. Getting somewhere new is after all why I go touring.
The industry is evolving fast and the latest adventure bike sector is hugely exciting, bikes are getting stronger, lighter, more adaptable and faster. Old traditional touring brands are still making the same 26 inch bikes and they look prehistoric in their approach to touring.
There are 6 main bike wheel sizes you could use and a new one seems to appear each year;
1:700c or 29er wheels
These are found on most road, gravel and adventure bikes and many new-ish mountain bikes this is actually the same wheel diameter however on a mountain bike the rim is wider and the tyre is much fatter so this makes the actual diameter bigger hence the 29inch name. The 700c used for road bike wheels and tyre sizing is the diameter excluding tyres. Strong, roll fast, efficient and well established wheel size these are what you should be touring on full stop for efficient riding on all but the more niche tours. There is a reason why road bikes and XC mountain bike racers use this size wheel.
2: Standard 26 inch mountain bike wheels
This was just about the global common standard mountain bike wheel and is found on bikes all over the world. It was by far the easiest size to pick up spare tubes, spokes and tyres in remote places. However I would never ever tour on a 26inch wheel again (see fatbike section below for possible exception!).
This was a bike packing trip we did in the South Chilcotins in Canada, we used 26inch wheels but things have changed and we would now use a 29er everytime, but they weren’t available widely at the time. In 2006 we used 26 inch wheels for touring on and off road across New Zealand and it was much harder work than it could have been. Since those tours I’ve never used 26 inch wheels again. Recently I challenged this and took an old 26 inch MTB out for a weekend in the Cairngorms, it was a frustrating decision and the bike went straight to the back of the bike cave again afterwards! 
3: Old school 27 inch wheels
If you’re using an old retro racing bike then it might well have these wheels. They are pretty much obsolete now and hard to find spare tubes, rims, spokes and tyres for so don’t consider touring far from home on one of these. You can stretch 700c tubes on but it’s not ideal setup.
4: 650b or 27.5inch the new fad in mountain biking
This is has been around a while but is currently very on trend for gravel and mountain bikes. It fits between the 700c/29er and 26 inch mountain bike wheel size and marketing companies say it offers the best of both. On an enduro bike it makes some sense but even these are swapping to 29ers for pure speed. While the size is marginally more efficient than a 26inch wheel it offers no advantage for long haul touring on paper. It doesn’t offer an efficiency advantage and you just wont find many spares out on the road. However the latest gravel bikes can fit 650b wheels that take a much wider tyre – up to 2.3″. This makes your one bike super adaptable and for less remote parts of the world adventures it makes sense because you can cover rougher ground on the same bike that still feels at home on the roads and have drop bars for the head winds. For tours on better surfaces put the 700c wheels back in and you have two bikes essentially from the same bike.
While you can stretch 26in tubes easily to fit 650b, it is getting replacement tyres/spokes that is the biggest issue in remote places. I have enjoyed using 650b on bikepacking routes where I’m unsure how rough sections might be here in Scotland. The point is that they just aren’t as fast or comfortable as 29ers but consider them if your bike can be adapted for different tours by swapping to wider 650b wheels.
5: 27.5+, 650B+ or Fat bikes
Fat bikes were created a few years back to ride through soft snow and other loose surfaces. They are ideal in flat snowy places, sandy beach riding or even across boggy ground. However while they might be fun to ride, they are hideously painful to ride over long distances when the width is not really needed. They are getting lighter but still heavy and the huge contact patch with the road creates more drag than towing a tandem.
The even newer fad is to stick a fatter 3″ tyre onto a 27.5 wheel and use it on a 29er frame, it’s called a 27+ and not something that most tourers will be interested in unless they plan on encountering lots of snow or sand as part of their adventure. On sandy looser routes they make sense as they are less weight than fat bikes but still float better. In the rougher parts of Iceland they make a lot of sense on the volcanic dust and loose gravel. They are clearly less efficient on road but in theory should be easier to fit in an unmodified bike. It is also fairly cynical to assume that the industry wanted another new standard to sell that was undeniably fun, but was it really needed? I guess if it opens up new options the answer is yes.
6: 20 inch folding bike wheels (or BMX??)
I would never promote pure cycle touring on folding bikes if it were not for logistical reasons as the small wheels are incredibly hard work. There is no rolling inertia that keeps you freewheeling, as a result you have to work the pedals a lot more to maintain a steady speed. I can certainly see the attraction for short city tours or train/bus touring because it saves the stress of transporting bikes and trust me we’ve had a lot of stress get bikes on buses etc. You will also struggle to find any spare tyres and tubes in remoter areas so use them where needed for a specific purpose.
Conclusions
For a pure cycling experience a 700c or road bike wheel size is much less effort and way more efficient. There is no debate here, that is a fact. The big diameter gives greater rolling inertia and it is much easier to maintain a decent speed. If you need a stronger wheel or are heading off-road get a 29er MTB wheel.
It is a myth that bigger size wheels are always weaker, you just need to pick the right strong set of wheels with appropriate number and style of spokes. If you are of a lighter build you can get away with ridiculously light 700c wheels for touring. For example Marion has used Fulcrum Racing 5 wheels with 18 straight pull spokes on the front and never had an issue. What you do need to be careful with is the width of the rims/tyres, as fat MTB rims will not fit in traditional road caliper brakes. They will work with cantilever brakes and disc wheels will now work with the latest road/touring/gravel/CX bikes equipped with disc brakes.
The only reason to use smaller 26 inch wheels I’ve heard is that for travel in remote areas of Africa the chances of picking up spares is less likely for 700c or 29er wheels. The main reason 26″ persists is that old skool brands of tourers and tourers are stuck in their ways and are getting left behind as bike travel evolves at a fast rate. People are getting outdated advice and are missing out although this is changing fast as gravel/adventure bikes have taken centre stage.
The next generation of adventure bikes will fit an ever wider range of 700c tyres and even fat 650+ gravel tyres. This is the logical next step – a solution for pretty much any landscape/tour and I’m excited to get involved!
Sets of good 29er wheels include the following:
Hope Pro2 Evo
Hope make solid hubs that I have relied on for years. THese use straight pull spokes that are stronger and easier to replace. But take some spokes with you just in case, as they are hard to find!
Custom Shimano Wheel A good value and strong option is a Shimano hub with any Mavic rim, the more you spend should improve durability in the hub but only a bit. Any combination will be reliable and these use standard spokes.
Kinesis Crosslight CX wheels Set of good disc compatible CX Wheels ideal for touring and I have tested extensively without any major issues:
Fulcrum Racing 5 CX wheels
These are the same as the road wheels but with better seals, so light and not for larger people or 4 pannier tourers.
Sets of strong road wheels
THese are what Marion has used for around 10,000km or touring without issue, non standard spokes but seem very robust: Fulcrum Racing 5 road wheels
For heavier people I would go for a Shimano Tiagra or 105 hub on a Mavic A319 or A719 rim. Dependant on budget, the A719 is a great upgrade whereas the hubs will perform to similar level.
Custom Shimano Wheels
