Again SB, you are missing the point of the OP. The question was not about HIS bike, just what would work better in a certain condition. I have always contended that a 19" front is the best multi use tire for a moderate dual sport bike. As to BPs sportster I do not know exactly what he plans for his suspension. If he is doing anything like JTH sportster then a 21" is still the best option. I am really curious though if you have ever tried a 19" tire on your CR450F for the desert? I am not sure if you noticed the measurements, but that three fifty actually measures narrower than the 21" on your 450f. Maybe be an optical illusion though. I just went out to MY garage and measured MY 1965 Yamaha Ym1 rear tire, which is a 3.50-18 and it measure exactly 3-1/2" and so does the more knobbie looking tire that came off of it. And yes I have ridden it in the dirt. I also measured my airhead R80G/S which has a 90/90-21 and it measures almost 3-3/4" wide although optically looks narrower that the smaller diameter on my old yami. If this discussion was whether or not the taller sidewall was better in the dez for flats or pinches...different discussion. PS: I love old and vintage things so none of this is because I think old is bad....my daily driver is a 1949 Studebaker truck with a V8 conversion....not a small block chevy like most but a 1963 Studebaker V8 conversion that I did myself. It still runs the stock 3 on the tree with OD and the stock 5.56 geared Timkem split center diff. No A/C. No PS. No PW....my current motorcycles are a '96 RT, an '86 G/S, an '83 Honda POS project and a 1965 Yami Ym1 305cc 2 stroke twin...I obviously love old and vintage.