Originally Posted by
cyccommute
I'll create a firestorm but here goes:
Spoke count and the spokes are far more important to the wheel's strength than the rim. The spokes do all of the heavy lifting while the rim is just along for the ride. If you build the wheel with 36 (or more) spokes like the DT Alpine III, Wheelsmith DH13 or Sapim Strong combined with just about any rim, you'll have a strong wheel. If you build a wheel with a heavy rim and weak spokes, you'll just have a heavy wheel. The broken spokes on your current wheel are a prime example of this.
Rim width isn't all that critical either. I run 17mm rims on my mountain bikes with 2.2" (54mm) without problems. A 35mm tire can easily be run on a 14mm rim. You might not be able to pump it up to 120 psi but you probably don't want that kind of pressure for off-road riding anyway.
given that wheel longevity is also a function of how much rim can be abraded away from braking before it's strength is compromised a thicker sidewall will make for a longer life wheel. Lighter rims will also have lighter flange holding the bead which will be more susceptible to being bent when bottoming out on sharp edges. Building with 15/17 butted spokes and low spoke count on a heavy rim wouldn't make sense for a heavily loaded wheel and neither would a light rim with heavy spokes.
There's more reasons than marketing that different weight/dimension rims are used for different applications.