* 6x5.5" (6 on 5.5 inches): This is the most likely pattern for most 2004 GMC Sierra models. This means 6 lug nuts arranged on a circle with a diameter of 5.5 inches.
* 8x6.5" (8 on 6.5 inches): Less common, but some heavy-duty models or optional wheels might have this pattern.
To be absolutely certain, you need to:
1. Check your owner's manual: This is the most reliable source.
2. Look at your existing wheel: The bolt pattern is usually stamped on the back of the wheel.
3. Check the sticker on your driver's side doorjamb: This sticker often lists tire size and other vehicle specifications, sometimes including bolt pattern.
Don't rely on online information alone, as variations exist across trims and options. Always verify with your vehicle's documentation.
