You know, so that the tire spins in a direction opposing the little arrow embossed on the tire?
Well, one thing that happens is that the rolling resistance must get a LOT WORSE. Like the difference between a bell javelin helmet and a giro aspect helmet at 20mph worse.
Not to mention the handling feels decidedly squirrelly.
Any other thoughts on the deleterious effects of putting a tire on backwards? I’m not sure there are any other obvious negatives but I was surprised that rolling resistance got so much worse.