Moots FrostTi: Paul Hubs + Surly Marge Lite Rims
This is the wheelset without tires. The next page shows with tires.
This view from above just how wide the rims are, more on that below.
Rim width and rim weight
To accommodate the huge 3.8" tires, the rims are very wide.
In this photo, the rim strip has been installed.
Observe the cutouts through which the rim strip is visible: at not more than ~12 PSI, this is sufficient to keep the tire from bulging out, and the metal saved drops the per wheel weight by 390 grams for each wheel = 1.7 pounds for the wheelset.
The Paul Components Engineering hubs are extra wide and extra beefy.
This is the rear wheel.