1999 GMC 1500 Club Coupe Bolt Pattern
Checking fitment for your vehicle? Below you will find the factory bolt pattern (also known as the lug pattern) for the 1999 GMC 1500 Club Coupe, along with offset and center bore data.
| Bolt Pattern (Lug Pattern) | 6x139.7 (6x5.5") |
|---|---|
| Lug Nut / Bolt Size | 14x1.5 |
| Center Bore (CB) | 78.1 mm |
| Offset (ET) | 20-30 |
| Torque Specs | 100 ft-lbs (135 Nm) |
Imperial Match: 6x139.7 is commonly referred to as 6x5.5" in US Standard.
1999 1500 Club Coupe — Year-Specific Fitment Context
The 1999 model year is the final year of the GMC 1500 Club Coupe's 6x139.7 bolt pattern run (since 1992). Wheels from any 1992–1999 GMC 1500 Club Coupe are cross-compatible with the 1999 model.
GMC 1500 Club Coupe Bolt Pattern by Year
The table below shows how the 1500 Club Coupe's wheel specifications have changed over the years. The 1999 model year is highlighted.
6x139.7 Pattern Context
This bolt pattern appears on 1067 vehicles in our current database and is considered common.
Examples of other vehicles using 6x139.7:
Expert Buying Guide for 1999 GMC 1500 Club Coupe
For your 1999 GMC 1500 Club Coupe, the 6x139.7 bolt pattern and 78.1mm center bore are critical. Aftermarket wheels often have a larger center bore (e.g., 78.3mm), requiring hub-centric rings to prevent vibration and ensure load is on the hub, not the lugs. Offset must stay within 20-30mm; deviating can cause rubbing or poor handling. Always use the correct 14x1.5 lug nuts with the proper seat (cone or ball) matching your wheels. Improper seating can lead to wheel loss. Verify thread engagement and torque to spec.
Historical Fitment Data Reference
In our dataset, GMC 1500 Club Coupe appears from 1992 to 1999 (8 model years). Across recorded model years, this model generally keeps the same bolt pattern.
- Observed bolt-pattern variants for this model: 1
- Observed center-bore variants for this model: 1
- Observed lug-size variants for this model: 1
- Observed total offset span across years: 50.0 mm
Quick Tips & Safety Warnings
- ✅ Re-torque lug nuts after 50-100 miles of driving to account for settling.
- ✅ Avoid using universal fit wheels without verifying center bore; hub rings are mandatory for safe fitment.
- ✅ Check for clearance with brake calipers and suspension components, especially with lower offsets near 20mm.
- ⚠️ This fitment uses a wide offset range. Check brake clearance and fender clearance before buying wheels.
- ⚠️ Torque lugs in a star pattern to 100 ft-lbs (135 Nm), then re-check torque after 50-100 km (30-60 miles).
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1999 GMC 1500 Club Coupe — Frequently Asked Questions
What is the bolt pattern for a 1999 GMC 1500 Club Coupe?
The 1999 GMC 1500 Club Coupe uses a 6x139.7 bolt pattern (also called lug pattern or PCD). The center bore is 78.1mm and the offset is 20-30mm.
What other years of GMC 1500 Club Coupe have the same bolt pattern as the 1999?
The GMC 1500 Club Coupe uses the 6x139.7 pattern from 1992 through 1999. Wheels from any of these model years are dimensionally compatible with the 1999, provided the offset and center bore also match.
Can I put aftermarket wheels on my 1999 GMC 1500 Club Coupe?
Absolutely. Just ensure the aftermarket wheels have a 6x139.7 bolt pattern, an offset near 20-30mm, and a center bore of at least 78.1mm (using hub rings if larger).
Do 1999 GMC 1500 Club Coupes use lug bolts or lug nuts?
The 1999 1500 Club Coupe requires 14x1.5 hardware. Check your specific trim to ensure you use the correct conical or spherical seating.
How do I measure the bolt pattern on my 1999 GMC?
The 1999 1500 Club Coupe uses a 6x139.7 pattern. For 4, 6, or 8-lug wheels, measure center-to-center across opposite holes. For 5-lug, measure from the center of one hole to the back of the opposite hole.
What does 20-30mm offset mean for the 1999 1500 Club Coupe?
An offset of 20-30mm means the wheel's mounting surface is 20-30mm away from its centerline. Changing this value drastically can affect suspension geometry and wheel bearing wear on your GMC.
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