Finally the last step in the process is to drill pilot holes to mount the remote reservoirs to the frame. After mounting these units with the supplied hardware, all four of the reservoirs must be filled with nitrogen. With the T-Rex system installed, we were able to fit a set of 35x12.50x18 Toyo Open Country M/Ts on 18-inch aluminum Weld Racing EVO wheels. The wheels and tires are available through T-Rex Engineering. You can also get a package deal with the T-Rex suspension system, Toyo tires and Weld wheels at select Dodge dealerships throughout California.