https://www.pcgamer.com/spintires-mudrunner-free-ridge-dlc-will-add-a-new-map-mode-and-vehicles/

Spintires: Mudrunner, the game about driving Soviet vehicles through Soviet mud for no particular reason, is getting new, free DLC at the end of the month called The Ridge. It adds a new coastal map to the game that's bisected by a mountain ridge players can cut across to save time—if they're willing to take the risk. 

The Ridge also adds two new vehicles to the Spintires world, the D-538 heavy duty tractor, and the B-6A lightweight tractor. It's a safe bet that neither of these machines will lay down a ten-second quarter mile, but they can probably drag a small office building, and you can use them on any map in the game as long as you've unlocked enough progression points.