It was nice knowing you, Greg.

 

As others have said, it's mostly about the effectiveness of how well it eliminates water. It has all those channels where water escapes the main channels. By putting them on the wrong way around, you're fighting the design. I don't expect it would make any difference at all in the wet.

Insurance companies look for any reason to not payout. Would they use that as an excuse if you crashed in the rain?

 

Correct direction of tire roll = water evacuation. Opposite direction of tire roll = water collection? Should have no real issue in the dry, perhaps noisier, since directional tires are also tuned for road noise.

Some tires are marked "outside" on one face. Not sure if this is because they have that wheel protection ridge on that side, or some hidden engineering below the surface. For liability reasons, you may have a hard time finding a tire shop that will mount the tires in the wrong direction of roll or with the outside face inside.

 

These are asymmetric tyres, they are designed with different stiffness to the outside shoulder compared to the inside shoulder of the tread, this enables better cornering.

Putting these on the wrong way round will result in worse handling in all conditions.

 

+ 2

 

it never amazes me the lengths people will go to save money to sacrifice safety of themselves and others.

 

Thats usually what happens when you buy a car you can't afford to properly maintain. Its like being house-poor, I suppose?