Originally Posted by
Skulking
I'd like to circle back to the original question and see if I've understood everything correctly. It seems like the answer is actually that there is no reason that a rim would be for rim brakes only, but because of how the spokes are laced, a wheel may only be suitable for rim brakes. If a wheel is sold fully assembled with the spokes laced in such a way that is only appropriate for rim brakes, then it would make sense for the rim to be labeled as only being suitable for rim brakes, but if it was desired the spokes could be re-laced appropriately for disk brakes because there is nothing specific to the rim which makes it only suitable for rim brakes. Have I correctly understood the gist of this thread?
It's not only the spokes that experience differences in forces between disc and rim brake wheels. The connections between the ends of the spokes will also experience equivalent amounts of force. That includes the nipples and spoke holes in the rim and hub flange. How much difference compared to the total load of the entire system? You'd have to calculate that yourself. If you want to know if rims labeled for rim brakes only can be used for disc brakes (even after relacing), I think only the manufacturer can tell you.