This contains an Alcoa 22.5x11.75 widebase rim with a compatible Michelin XZY3 385/65R22.5 tire. The rim is a thoroughly de-polied version of RBR-DUK's Alcoa widebase. The combined poly count is less than 9000 tris and so should perform well on mid- to high-range computers.
RBR-DUK - original rim model
Download the zip file directly to My Documents/American Truck Simulator/mod. There's no need to unpack it. Enable it in the in-game Mod Manager. Enjoy!