What size are stock TBSS wheels?
Stock TrailBlazer SS wheels are 20 inches in diameter, specifically 20x9 inches, paired with a 5x115 mm bolt pattern and 275/40R20 tires. This size is designed to balance performance handling with fitment for factory brakes.
Stock TBSS wheel size in detail
The TrailBlazer SS (TBSS) was equipped from the factory with 20-inch wheels that measure 20 inches in diameter and 9 inches in width. The wheels use a 5-lug bolt pattern of 115 mm and are designed to clear the TBSS’s factory brakes without modification. The typical tire pairing for these wheels is 275/40R20, which suits the wheel width and overall vehicle stance.
The figures below summarize the key specifications you’re likely to encounter when identifying or replacing TBSS wheels:
- Wheel diameter: 20 inches
- Wheel width: 9 inches
- Bolt pattern: 5x115 mm
- Center bore: approximately 66 mm
- Offset: roughly +40 to +60 mm (positive offset)
- Tire size (stock): 275/40R20
These specifications work together to ensure proper brake clearance, alignment with the suspension, and adequate tire contact patch for the TBSS’s performance profile.
Notes on year-to-year variations
While the 20x9, 5x115, 275/40R20 setup is typical for most US-spec TrailBlazer SS models, there can be minor variations based on production year or regional specifications. Always verify the exact spec on your vehicle through the glovebox VIN sticker, the owner’s manual, or by measuring the wheel and consulting GM parts data for your exact VIN.
Why the size matters
Choosing the correct wheel size is crucial for brake clearance, caliper fit, and overall handling. The 20x9 inch wheel provides enough clearance for the TBSS’s braking hardware while maintaining a stance that suits its performance intent. The 275/40R20 tire size balances grip and ride comfort, helping to preserve steering response without unduly increasing rolling resistance.
If you are considering aftermarket wheels or tire upgrades, ensure the replacement maintains the 5x115 bolt pattern and keeps the overall diameter close to stock to avoid speedometer errors and drivetrain stress.
Summary
In short, stock TBSS wheels are 20x9 inches in diameter with a 5x115 mm bolt pattern, typically paired with 275/40R20 tires. The setup provides compatible brake clearance and performance handling while preserving stock alignment. Always confirm exact specs for your vehicle via VIN-linked sources or GM’s official parts data before purchasing replacements or upgrades.
