Instructions
Steal a car or enter one of your own vehicles. Only cars, trucks and other four-wheeled automobiles can have rims added. Motorcycles, ATVs, golf carts and other special vehicles are not eligible for rims.
Open your map and locate the nearest modifcation shop. The shops are called Loco Low Co, TransFender and Wheel Angels. Loco Low Co and TransFender have several locations throughout the city and each location carries the same items. Wheel Angels has only one location, in San Fierro, and must be unlocked by completing driving school, purchasing Wang Autos and completing the Doherty collection missions for Ceaser.
Place a marker on the map indicating the nearest modification shop. Use this marker to help you navigate to the location while driving in the car that you want to modify.
Pull the car into the garage of the modification shop. Doing so will bring up a menu where you can purchase modifications for the car or truck.
Navigate to the tires section and purchase a set of big rims. The vehicle will be automatically modified. Add any other modifications you like such as paint colors, spoilers or hydraulics.
Drive your modified car to your nearest safe house. Park the car in the garage or closest glowing parking space to save the modified car for future use.