To plagiarize a theme from our last two-term president's
campaign I offer you this; "It's the wheels stupid! After the
integrity of your bicycle frame, the wheels determine many aspects
of efficient cycle touring. The wheel is everything and for a decade
now I have had the great fortune to have never replaced a broken spoke.
Yes I've cracked rims at the eyelets because the rims were not a double
ferruled, but that has been overcome with the use of a Mavic 618X-
36 holes, on a basic Shimano XT hub.
There are many choices of tires and they must
match both the road surface you intend to ride and the total weight
of rider and gear. Knobbies work very well for dirt -the larger
the better. I like a 2.3 for gravel and dirt. For mixed surfaces
where there is more pavement than dirt a semi-smooth 1.75 makes
for an awesome ride.
Tubes like tires come in a wide variety of options
for both weight and size. Some ultra-lights work well, but they
lose pressure more quickly.
A seemingly insignificant element that has given me
fits over the years is that silly little piece called the rim strip.
The challenge I have had is with the rim strip wearing little slices
in the tube and causing the deadly slow leak. Woven cloth ones work
the best on a really long tour.