I've ridden the GravelKing 32s because that was the widest I could fit. Many of the other riders are on 29ers with much wider tires. Our "gravel" is clay roads with random sections of washouts and washovers of loose stuff. Also creek crossings with gravel in the beds. On flats and climbs, my relative speed was faster than expected. On descents and creek crossings, the 32s sucked and I was painfully slow. If I had better handling skills and was comfortable with the bike sliding around, of course the descents could have been faster. Since even nice tires are not a budget breaker, no reason not to try wider if they fit.