invalidredneck (can't change focus forums username)
A few days ago, an old friend of mine, bleachSNAK3 found a fix. It took him many hours to figure it out. Unfortunately, the only version that works is SpinTiresModv1.7.6
Install SpinTiresMod normally. Then go to C:\Program Files (x86)\SpintiresMod\Install\Win32/Spintires Mudrunner and copy MudRunner4GBPatched.exe and steam_appid.txt into the game directory (every 4GBPatched.exe is different for every version). Then, in the directory create a new .txt document called MudRunner. In that text document, type the steam game number: 675010, and save. Create a desktop shortcut to MudRunner4GBPatched.exe and always launch the game from that.