Cobb Performance Series ST-01 Wheel 18×9.5 ET40 5×114.3 – Gunmetal – 2015-2026 Subaru WRX / 2015-2021 STI / 2018-2026 Forester / 2015-2026 Outback / 2023-2026 Crosstrek

Cobb Performance Series ST-01 Wheel — 18×9.5 ET40 5×114.3 — Anthracite Gunmetal

The Cobb Performance Series ST-01 wheel in Anthracite Gunmetal is a flow-formed 18×9.5 ET40 5×114.3 wheel developed for the Subaru WRX and STI. Flow-formed construction provides improved strength-to-weight ratio versus cast wheels. This listing is the Anthracite Gunmetal finish — all ST-01 variants share the same 18×9.5 ET40 5×114.3 specification.

DETAILS

• THIS LISTING: ST-01 — Anthracite Gunmetal finish
• Size: 18×9.5 — ET40 offset — 5×114.3 bolt pattern
• Construction: flow-formed aluminum — stronger and lighter than cast
• Center bore: 56.1mm — correct for Subaru WRX and STI
• Fitment: 2015-2021 Subaru WRX and STI, 2022-2026 WRX
• Sold as set of 4 wheels — tires not included
• Available in 7 finishes — this listing is Anthracite Gunmetal

ST-01 Wheel Specifications

Size	18×9.5
Offset	ET40
Bolt pattern	5×114.3
Construction	Flow-formed aluminum
Center bore	56.1mm — correct for Subaru WRX/STI
Includes	4 wheels per set — tires not included
Fitment	2015-2021 WRX / WRX STI, 2022-2026 WRX

Flow-Formed Construction: Strength-to-Weight vs Cast Wheels

The Cobb ST-01 Performance Series wheel is a flow-formed aluminum wheel developed specifically for the Subaru WRX and STI. Flow forming is a manufacturing process where the wheel barrel is stretched under heat and pressure over a mandrel — the process aligns the aluminum grain structure along the barrel, producing a wheel that is stronger in the areas that experience the most stress while using less material than a cast wheel of equivalent strength. At 18×9.5 with ET40 offset on a 5×114.3 bolt pattern, the ST-01 fills the WRX and STI wheel wells correctly without requiring offset correction spacers.

18×9.5 ET40 Fitment, Anthracite Gunmetal Finish, and Tire Sizing

The ST-01’s 18×9.5 dimensions support wider performance tire fitments than the factory 8.5-inch wheels — 265/35R18 or 255/35R18 are common choices, providing a wider contact patch for improved cornering grip. The ET40 offset positions the wheel face at the correct depth in the wheel well for the factory suspension geometry. Available in seven finishes — Bronze, White, Silver, Blue, Gold, Satin Black, and Gunmetal — the ST-01 provides color options to complement or contrast the exterior color of the car.

What’s in the Box

• Cobb ST-01 wheels (set of 4)
• Center caps
• Hardware

Why Choose Cobb Tuning

Cobb Tuning has been developing performance software and hardware for turbocharged enthusiast vehicles since 1999. Founded in Austin, Texas, Cobb built its reputation on the Accessport and expanded into a full catalog of hardware engineered to complement it. Every OTS map is developed in-house on real vehicles, and every hardware product is validated as part of a complete system — not sourced and sold in isolation. That integrated approach is why Cobb produces consistent, reliable results across the builds we see every day.

The RallySport Take

The Cobb ST-01 in Anthracite Gunmetal is the wheel developed specifically for the WRX and STI platform. The 18×9.5 width supports wider performance tires than the factory 8.5-inch wheels, the ET40 offset is correct for the factory suspension geometry, and the flow-formed construction reduces rotating mass versus cast alternatives. The gunmetal finish suits a range of WRX and STI exterior colors — select the combination that best matches or contrasts the car’s exterior.

Fitment

Year	Make	Model	Notes
2015-2021	Subaru	WRX	5×114.3 ET40
2015-2021	Subaru	WRX STI	5×114.3 ET40
2022-2026	Subaru	WRX	5×114.3 ET40