A hub is laced to a rim with spokes and nipples in order to create a wheel. Elementary I know but semantics are important if the aspiring bike tourist is to make him/her self understood.
I don’t want to go into how to build a bicycle wheel because there are hundreds of YouTube videos and several good books available on how to do it. (Jobst Brandt’s The Bicycle Wheel being the paradigm for books)
I will say there are a couple of elements that make a good, strong touring wheel, and these things may not be intuitive. Here is a good touring wheelset:
Notice there are a lot of spokes…36 per wheel to be exact. Each spoke crosses 3 other spokes on the way from the hub to the rim, creating a structure of amazing grace, elegance and stability. Some recently popular wheel designs with as few as 18 spokes per wheel rely on the strength of the rim for stability of the wheels which results in a heavier rim. (unless the rim is carbon fiber) Spokes actually are made in various gauges or thicknesses and a visceral reaction might be to assume that thicker spokes will result in a stronger wheel….but not so fast. The spokes flex with every revolution of the wheel, no way around it. So making the middle sections of the spokes thinner than the ends (called “double butting”) allows the spokes to flex and adds strength where they are most likely to fail; at the ends. Get Mr. Brandt’s book if you want to know the excruciating details.
In my experience, based on building dozens of wheelsets, there are only two companies that consistently make high quality rims: Mavic and Velocity. The Mavic A319 rims are a super solid choice for a touring wheelset. For hubs it would be hard to beat the Shimano Deore hubs for value. Steel axles and loose ball bearings make a durable, user friendly combination.
I built these wheels for a customer who reminded me he has disc brakes. Disc brakes require a disc specific hub onto which the brake rotor is bolted. These wheels don’t have a disc specific hub. That’s right, I’m a professional and an expert. I’ll be selling this wheelset and the customers new wheels are on the way.