Has anyone changed the front tire to a 21 inch?

I have been about to sell the Capo and have considered Honda Africa Twin, BMW 800 GS, and Triumph 800. Thought I would do fine with my Husky 610 and BMW R1200RT but my main riding partner is looking at going to an 800 GS after realizing that of our 5 day dualsport ride on our Husky singles the only portion that would not have been more comfortable on one of the large dualsports was about 3 hours of very poorly maintained backcountry road from point A to point B. We could have skipped that portion of the ride without taking any enjoyment out of the week of riding. It occurs to me that the only reason I am attracted to the 3 bikes mentioned over the Capo is their 21 inch front tires.