* On the driver's side doorjamb: The sticker there will list tire size and other specifications that indirectly point to the lug pattern.
* Your owner's manual: This will definitively state the lug pattern.
* The wheels themselves: The lug pattern is often cast into the wheel.
* A reliable online parts database: Enter your VIN (Vehicle Identification Number) to find the precise specifications for your truck.
Don't rely solely on generalized information. Always double-check before buying wheels or tires. Using the wrong lug pattern is dangerous.