Originally Posted by
ItsJustMe
For touring especially in multiple countries, I think 26" is the logical choice. Anyplace that has bicycle tires at all will have 26" tires. 700C, not nearly the case. Some countries it may be very difficult indeed to buy 700c tires.
I can only speak for EU, Americas and SE Asia/coastal China but every bike shop with a 26"/559 will have a 28"/29"/622/700c tyre.