this question pops up perennially....
and the above is my final answer with a few caveats,,like those rims sizes work better but,,,,no buts!!!!,,,and,,,,
..and one must also take the brand,,,the model,, the terrain,,,the tire pressure,,,the velocity,,,the weight of bike ,, the riders skills and aesthetic requirements into consideration.
FYI,,,once upon a time we used many Sun rims successfully until better alloys came along...they were heavier like the Dirt Stars...but a softer alloy.
In recent years Buchananns who build these rims in their California facility decided to improve the quality..like aligning the two ends [that are butt welded together] for a change and making them rounder and lighter BWOE...they accomplished this by over-sizing the circumference and then machining the excess off in a lathe,,,voila a lighter,straighter rim BUT not as strong....a little extra beef does matter...thus i have not used or recommended a Sun rim in years for the dual sport scene.
FYI,,,,weight matters,,,not just the benefits of unsprung weight,,easier handling..thus i'd rather have a heavy n tuff rim over a lighter, soft alloyed one,,,and a light and tuff one over a heavy n tuff one
FYI,,,the off-road improvement in handling of the narrower rims is far greater than any diminishment of on road handling characteristics,,,,theoretically the wider rims would be better with lower profile/aspect ratio tires which need them to keep the sidewalls supported..
FYI,,,the Excel A-60 is clearly my favorite choice for strength/$$$ value.
unfortunately it is cursed with an obnoxious silver pinstripe etched full circle,,,there are folks that have returned the wheels and switched to other rims because it doesn't meet their aesthetic requirements...hey i'm with you..it takes an additional circa $100 to strip the color/ sand the stripe off /rebuff to a shine and re-anodize black
....and to add insult to injury,,,there are no matching rears available for 90% of the rims we need for your dual sport bikes....they only come in the standard du jour 1.85 &2.15x19 rears. excels link=
FYI,,truth be told not everyone rides like Pyndon and Neduro so have more options to choose from....which brings me to the point that there are some riders with the trickest suspensions and state of the art wheels/rims etc who simply plow through everything ,,,are cluelless to the art of modulating throttle control,,pulling on the handlebars and lofting the front end over that log or rock.....
FYI,,,some rims are better in muddy conditions....several years ago DID had rim with arounded profile that shed mud incredibly well,,,unfortunately it had a 6000 series alloy that was too soft for the serious off-roader...the dimpleless Sun and Excel rims collect les dirt and the A-60 has the next best mud slinging profile....mud buildup can seriously affect your handling
FYI,,,tire pressures......to avoid pinch flats the heavier the bike the more pressure is better circa 38psi+ for the big iron on road and 30psi off road,,,
i hear reports all the time that 20-26 psi is being used by some very respected sources...perhaps they can chime in what they use on what and where....
'nuff for now gotta head to work