oh, and since the carcass is stiffer, they keep closer to the static radius I would guess, where as the stockers can squish down and give the effective radius of like an 18" tire at times, since they're balloons!! Not that all tires don't change effective radius, but these are stiffer. I've heard people comment that the blaster rides a little rougher over rough terrain...I guess that's probably true to some extent, but it never bothered me. You gotta get the PSI correct for your weight, ya know. You really can't go wrong with these tires IMO....unless you were trying to use them for like motoX racing....they're probably not the best for that, haha. If you go through muddy fields, muddy trails, dirt roads, sand pits, rocky woods with mud inbetween and all sorts of variable terrain, you'll love em.