Tires not working

Maybe you need to add the tires manually with that mod.
Do this from the part selector menu.

Or ask in that mod's thread (if exists), this section is not indicated for mod-related issues.

 

Using the Part Selector?
That's a basic function of the game.

Open the part selector (you can find that in the side menu that appears when you press ESC), then you need to find the wheels.
In most cars those are located under the 'Suspension' group.
Once you find, you will see that you can further expand the 'wheels' group.
On the lower lever of the menu, you will see the tires.
From there you can change them to any other tire that fits that particular wheel you installed.

It depends a lot of that mod, and on what mod those tires should be compatible with.
Check the mod's description, it should be saying something about where to find them.
Or ask directly in that mod's thread please, other users who uses that mod can assist you better.