We have crappy sand and gravel on our roads 7 months of the year because of the ice and snow all winter, that's why I have mud flaps.
I run low 14's consistently, but our DA is Brutal here, usually 3500+
it works out to firstname.lastname@example.org (DA corrected).
BTW, with my heavy 20's/Grappler's I'm lucky to even break 15 seconds and into the high 14's
Not only does the lower drag tire help my net gear ratio, the 17" tire/wheel combo is 30 pounds lighter (ea), less rolling mass, better grip,
...it also drops my ride height another 3" for better aerodynamics.