I thought DOTs were directional because the sipes only worked in that direction and reversal on wet surfaces would push water under the tire instead of away.
I heard it years ago at shops but did find some info pretty quick that seems to support the info
3. A directional type pneumatic tire comprising
a tire carcass having beads and a crown area and a tire tread on the tire carcass and wherein said carcass includes a plurality of confluent ply assemblies and said carcass is comprised of a like number of said confluent ply assemblies which are inclined in opposite rotary (or circumferential) directions of the tire and all cords in said confluent ply assemblies are positioned at a specific bias angle to a radial line at the center of the crown area of the carcass, all of said cords being positioned at a uniform bias angle and wherein the cords in the confluent ply assemblies which are inclined in one rotary direction have lesser strength than the cords in the confluent ply assemblies that are inclined in the opposite rotary direction.
. "Crazy people don't know they're crazy, but I know I am, so I must not be crazy"
I think it can be both reasons which is why I recommend talking to the tire guy at the track. Though DOTs will have a directional arrow for the sipes' water-dispensing function, I'm pretty sure some can be safely flipped, assuming the cord bias allows it.
I may be talking out of my a$$ but the tire guys know.
There is a grey blur, and a green blur. I try to stay on the grey one. -Joey Dunlop
I'm going to be trying the Dunlop 448/451 next time around. The 451 is the newest Dunlop rear slick. I have heard they are better than the UK. Sucks Dunlop prices recently went up like $20 a set.
I have been running the Michelin Power Slick Evo. They are a good tire, but I only get like 2-3 days out of a rear. The Michelin tire rep said don't flip their slicks. Dunlop and Michelin both have a harder carcass compared to Pirelli and Bridgestone.