Who's a tire expert

[blown motor]

I recently replaced the tires on my 15 Challenger SXT with a set of Nitto Motivo. On the sidewall of the tire it says OUTSIDE which is how they were installed. There are lateral thin slits that run at a slight angle from the first groove to the outside of the tire. Since all tires are the same these slits angle forward on one side of the car and rearward on the other. To me this doesn't make sense, shouldn't the all angle the same way? I called Nitto but only talking to someone in customer service that gave me generic answers and didn't address the science of tread design as I was hoping.

[Filthy Filbert]

I've not seen tires designate "inside" or "outside"   I have seen them call a specific direction for rotation though.

What does the inside sidewall say?  what if they both say "outside"?

Can you post a picture of the tread pattern? 

[MoparLeo]

It is called an "asymmetric tread pattern" That means that it is different from one side to another. The outer side of the tire sees more weight on a turn than the inside edge of the tire so the pattern and compounding is modified for more traction and decreased wear. Directional tires take this one step further in having the actual tread pattern optimized for traction, usually wet traction on a street tire by channeling water to the out side edges of the tires. When you get into the ultimate tire design, ultra high end vehicles like Ferrari, etc... can actually have 4 different tires on one car. One tire for each position l/f, r/f, l/r, r/r,  This also makes then VERY, VERY expensive.
https://www.tirebuyer.com/education/symmetric-vs-asymmetric-tires

[6bblgt]

   larger "blocks" on the outside for better cornering traction & siping in opposite direction for  non-directional tires

[Filthy Filbert]

I'd still like to see the OP post a photo of his tire tread pattern or better explain what he thinks he's seeing.  What you 2 said isn't wrong but is generic 'gee whiz' info that doesn't answer what @blown motor thinks he is seeing. 

[blown motor]

@Filthy Filbert You can see it in the picture 6bblgt posted. On the outside of the right tire the outside slits are angled downward and on the other tire they are angled upward. Since both tires are turning the same direction the I thought the slits would angle the same way. But maybe that makes no difference to channeling water away or performing any other function that the tire does.

[MoparLeo]

The majority of the water is channeled out of the wide grooves that run parallel to the tread, the small slots (sipes) allow the tread to scrub/flex while rotating.
In order for the tire to have the same tread pattern in each direction of rotation and still be asymmetrical, the outer edge would have to be at a 90 °angle to the tread or have a left side and right side tread pattern.
Makes no economic sense to have left and right ride tires on a conventional vehicle as it would be very expensive to manufacture and to retail to the public.
Only cars well in excess of 100K have tires that are designed that way./font]

[Filthy Filbert]

I had to go look at the tread on my tires...

It makes sense now.   The difference in a directional vs asymmetrical tread.

My tires are directional; but it doesn't matter inside vs outside of the tread.   I cannot rotate my tires from left to right.  Only front to back... and even then, only because they are the same size front to back. 

It should seem to me, that with your tread pattern, you CAN rotate left to right because the outside tread will remain on the outside.  Then it becomes a matter of tire size to determine if you can rotate front to back. 

(I'm gonna have to see. If those nittos are available in my size for the Dakota.   I hate not being able to do a real tire rotation to maximize tread life)

[blown motor]

@Filthy Filbert I will say I like the Motivo. The are smoother riding and quieter than the Firestone Firehawks that were on the car originally.

[MoparLeo]

You are correct . the outside will always be outside if you don't dismount the tires from the rims.
A directional tire has an arrow on the s/w to show direction of rotation.
An asymmetrical tire will just say inside/outside to let you know which side is to be mounted to the outside.