The most popular mods for "Spintires" are new truck models and new maps designed by members of the player community as of 2016. Also popular is the post-processing graphics suite and shader set known as ENB, which adds a hyper-realistic look to the "Spintires" world.
The most popular mods as calculated by player downloads at Worldofmods.com are various new player-created maps and truck models that extend the base game play and provide new challenges for "Spintires" players. The most popular map mod is called Map of the North, and it adds an entirely new player area that features a more wintry set of challenges to the usual swampy mud of the game's driving challenges.
Because "Spintires" is based around Soviet-era Russian and Eastern European trucks, it invites hypothetical what-if situations for modders to have fun with vehicle creations. Thus, the most popular truck mod introduces a player-made Ford F-350 Super-Duty vehicle to the muddy Russian backroads of the "Spintires" universe.
It is important to note that most map and vehicle mods are intended for single-player gaming only. These typically block general multiplayer access and disable Steam achievements if used. For players who wish to avoid that situation, the post-processing graphics enhancement known as ENB is the most popular mod for "Spintires" as of 2016. It adds cosmetic enhancements to the game for players with high-end graphics processors and at least 2GB of dedicated video RAM. It works without disabling multiplayer access or achievements.