Of course you can tour on a road or cyclocross bike. Yes, even if it is a racing bike with no dedicated attachments for racks. Even (especially!) if it weighs 17 lbs. Even if it’s made of aluminum or titanium or carbon fiber, with a carbon fiber fork with a carbon fiber steerer tube with carbon bars and deep-v aero-wheels.
Of course you can tour on it because it’s a bicycle and getting places is what it is for.
Somehow this view is thought to be radical and dangerous, certainly irresponsible. Everyone is best off, so the conventional wisdom goes, with a proper touring bike with long chainstays, relaxed geometry, a low bottom bracket, heavily reinforced tubes, 36 spoke wheels (inevitably “hand laced by an experienced and reputable wheel builder”), triple crankset, and raised handlebars. Apparently a road bike, heaven forbid one suitable for racing, will simply disintegrate if ridden further than 100k from home or on consecutive days!
Here’s another take. For many of us, the one bike pedaled most often, in the greatest variety of weather conditions, over smooth or broken asphalt, on gravel or dirt roads, with hundreds of shifts every ride that have to be perfect, the one that has to have reliable braking, where being light is terrific but where it can’t be so light that it’s fragile, the one that fits well because we spend so much time on it, the one that with halfway conscientious maintenance has to perform when we are riding at the limit of our fitness: that bike is a road bike.
If you already own a road bike, and if you’re intending to tour mostly on developed roads in North America, Europe or Japan, and if you are assiduously dedicated to traveling light, then the bike you have is fine.
To be clear. If you are in the market for a new bicycle to tour on and you have no ambitions later to ride it on frequent fast training rides and in weekend races, then it would be silly to buy a road bike. If the specific tours you envision involve rugged singletrack trails or are almost entirely on muddy, sandy, and broken dirt tracks, then a road bike is patently not the tool for the job. If you’re setting off for three years around the globe and are in the hunt for the most cost effective, versatile, reliable machine, well, frankly, that’s not a road bike. But a road bike will be perfectly capable for four days or three weeks or two months in Italy and Switzerland, down the west coast of the USA, or a circuit of Ireland or Nova Scotia or the South Island of New Zealand.
Axiomatic sounding assurances that one ought not to tour on a road bike originate in the well meaning but misguided attempt to answer a different question, namely what is the ideal touring bike if one is starting from scratch? I think that question has an answer, but it is completely irrelevant to the question of whether someone who has a road bike can tour on it. If that’s what’s in your garage and you want to bicycle tour, by all means do.
The main challenge to contend with in touring on a road bike is mastering the psychology of traveling light. A simple target is to carry not more than 25 lbs./11kgs of gear (not counting your shoes and the most basic outfit you will wear while riding). If you will be camping and cooking, this target can seem difficult to attain, but it is not out of reach. If you are not camping, i.e., if you’re staying in hostels or guesthouses every night and you have hot meals at local food stalls and otherwise carry a little bit of cold food, this target is dead easy. You’re not touring on Mars, nor, since you’re considering a road bike, are you touring in a place with many days in a row utterly away from resources.
Sure, yes, tour on a road bike. Maybe mount 25mm tires instead of your 23’s, and switch to pedals that allow for a recessed shoe cleat (or even flat pedals). But those changes aren’t essential.
A natural thing to wonder is how to carry gear.