1999 Chevrolet Silverado 1500 Extended Cab Bolt Pattern
Checking fitment for your vehicle? Below you will find the factory bolt pattern (also known as the lug pattern) for the 1999 Chevrolet Silverado 1500 Extended Cab, along with offset and center bore data.
| Bolt Pattern (Lug Pattern) | 6x139.7 (6x5.5") |
|---|---|
| Lug Nut / Bolt Size | N 14x1.50 |
| Center Bore (CB) | 78.1 mm |
| Offset (ET) | 16 |
| Torque Specs | 100 ft-lbs (135 Nm) |
Imperial Match: 6x139.7 is commonly referred to as 6x5.5" in US Standard.
1999 Silverado 1500 Extended Cab — Year-Specific Fitment Context
The 1999 model year marks the beginning of the Chevrolet Silverado 1500 Extended Cab's 6x139.7 bolt pattern era, which continued through 2013 (15 consecutive years). Wheels from any 1999–2013 Chevrolet Silverado 1500 Extended Cab are cross-compatible with the 1999 model.
Chevrolet Silverado 1500 Extended Cab Bolt Pattern by Year
The table below shows how the Silverado 1500 Extended Cab's wheel specifications have changed over the years. The 1999 model year is highlighted.
| Year | Bolt Pattern | Center Bore | Offset |
|---|---|---|---|
| ▸ 1999 | 6x139.7 | 78.1 | 16 |
| 2000 | 6x139.7 | 78.1 | 16 |
| 2001 | 6x139.7 | 78.1 | 16 |
| 2002 | 6x139.7 | 78.1 | 16 |
| 2003 | 6x139.7 | 78.1 | 16 |
| 2004 | 6x139.7 | 78.1 | 16 |
| 2005 | 6x139.7 | 78.1 | 16 |
| 2006 | 6x139.7 | 78.1 | 16 |
| 2007 | 6x139.7 | 78.1 | 16 |
| 2008 | 6x139.7 | 78.1 | 16 |
| 2009 | 6x139.7 | 78.1 | 26 |
| 2010 | 6x139.7 | 78.1 | 26 |
| 2011 | 6x139.7 | 78.1 | 26 |
| 2012 | 6x139.7 | 78.1 | 26 |
| 2013 | 6x139.7 | 78.1 | 26 |
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 Chevrolet Silverado 1500 Extended Cab
For your 1999 Chevrolet Silverado 1500 Extended Cab, the 6x139.7 bolt pattern is shared with 1999–2013 models, ensuring broad wheel compatibility. The 78.1mm center bore requires hub-centric rings for aftermarket wheels to prevent vibration and hub damage. Offset is sensitive; stock is 16mm, but deviations beyond ±10mm may cause rubbing or clearance issues. Always verify lug nut thread pitch (14x1.50) and seat type—use conical (60-degree) seat lug nuts for aftermarket wheels. Improper seating can lead to wheel loss. Re-torque after 50-100 miles.
Historical Fitment Data Reference
In our dataset, Chevrolet Silverado 1500 Extended Cab appears from 1999 to 2013 (15 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: 10.0 mm
Quick Tips & Safety Warnings
- ✅ Re-torque lug nuts to 140 ft-lbs after 50-100 miles of driving.
- ✅ Avoid wheels with offset less than 6mm or greater than 26mm to prevent rubbing or suspension interference.
- ✅ Use hub-centric rings if aftermarket wheels have a larger center bore than 78.1mm.
- ⚠️ 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 Chevrolet Silverado 1500 Extended Cab — Frequently Asked Questions
What is the bolt pattern for a 1999 Chevrolet Silverado 1500 Extended Cab?
The 1999 Chevrolet Silverado 1500 Extended Cab uses a 6x139.7 bolt pattern (also called lug pattern or PCD). The center bore is 78.1mm and the offset is 16mm.
What other years of Chevrolet Silverado 1500 Extended Cab have the same bolt pattern as the 1999?
The Chevrolet Silverado 1500 Extended Cab uses the 6x139.7 pattern from 1999 through 2013. Wheels from any of these model years are dimensionally compatible with the 1999, provided the offset and center bore also match.
What is the PCD for a 1999 Chevrolet Silverado 1500 Extended Cab?
PCD stands for Pitch Circle Diameter, which is the same as the bolt pattern. For the 1999 Silverado 1500 Extended Cab, the PCD is 6x139.7.
What does 16mm offset mean for the 1999 Silverado 1500 Extended Cab?
An offset of 16mm means the wheel's mounting surface is 16mm away from its centerline. Changing this value drastically can affect suspension geometry and wheel bearing wear on your Chevrolet.
How tight should I torque the lug nuts on a 1999 Chevrolet Silverado 1500 Extended Cab?
Refer to your owner's manual for exact specs, but always tighten the N 14x1.50 hardware in a star or crisscross pattern. Re-torque after the first 50 miles of driving.
What is the factory wheel offset for a 1999 Chevrolet Silverado 1500 Extended Cab?
The OEM offset for the 1999 Silverado 1500 Extended Cab is typically around 16mm. Depending on wheel width, a deviation of ±5mm is usually acceptable, but verify suspension clearance.
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