Ive ridden 43mm Gravel King tires (actually 40mm) on my Topstone on ST. Our version on L. I. Is mostly packed dirt, some sand, occasional roots, no rocks, not very hilly. The Gravel King SK tires have a surprising amount of grip in turns as well as rolling well on asphalt. I usually just stick to straight gravel/dirt roads and use my HT in our local ST.