The 2015 Subaru WRX utilizes two primary factory rim sizes depending on the trim level: a 17 x 8.0-inch wheel for the Base trim and an 18 x 8.5-inch wheel for the Premium and Limited trims. Both configurations feature a 5x114.3mm bolt pattern and a high positive offset of +55mm.
The 2015 model year represented a pivotal shift for the Subaru WRX. As the debut year of the "VA" chassis, it marked the formal separation of the WRX from the Impreza line. This transition brought significant changes to the vehicle's footprint, including a stiffened chassis and, most importantly for enthusiasts, a complete overhaul of the wheel specifications. Whether you are looking to replace a damaged factory rim, sourcing a dedicated winter setup, or upgrading to aftermarket wheels for a more aggressive stance, understanding the technical nuances of the 2015 WRX rim size is essential for maintaining safety, performance, and drivetrain longevity.
Factory Wheel Specifications by Trim Level
Subaru equipped the 2015 WRX with wheel setups designed to balance daily drivability with the car's rally-bred heritage. Because the WRX uses a Symmetrical All-Wheel Drive (AWD) system, rim and tire dimensions are more critical than on front- or rear-wheel-drive vehicles. Improper sizing can lead to differential strain or failure if the rolling diameters are not consistent across all four corners.
The Base Trim: 17-Inch Configuration
The entry-level 2015 WRX comes standard with 17 x 8.0-inch aluminum alloy wheels. These wheels are finished in a dark gunmetal gray and feature a multi-spoke design. The 17-inch diameter allows for a taller tire sidewall (typically 235/45R17), which provides a slightly more compliant ride and better protection against potholes. For owners in regions with poor road infrastructure, the 17-inch rim is often preferred for its durability and lower replacement cost for both the rim and the tire.
Premium and Limited Trims: 18-Inch Configuration
Stepping up to the Premium or Limited trims grants the owner 18 x 8.5-inch wheels. These rims are wider than the base version, which allows for a larger contact patch with the road. The standard tire for this rim is a 245/40R18. The wider 8.5-inch rim provides better lateral support for the tire sidewall during high-speed cornering, reducing "tire roll" and sharpening steering response. However, the 18-inch diameter results in a thinner sidewall, making the ride slightly firmer and increasing the risk of rim damage from sharp impacts.
The Critical Shift: Understanding the 5x114.3 Bolt Pattern
Perhaps the most significant technical detail for the 2015 Subaru WRX is the bolt pattern. For over a decade, the standard WRX used a 5x100mm bolt pattern, while only the higher-performance STI used the 5x114.3mm pattern. Starting with the 2015 model year, Subaru unified the WRX and STI on the 5x114.3mm (5x4.5 inches) standard.
This change is a double-edged sword for owners. On one hand, it opens up a massive world of aftermarket wheel options, as 5x114.3 is one of the most common bolt patterns in the automotive industry, shared by many Toyota, Honda, and Nissan models. On the other hand, it means that wheels from a 2014 or older WRX will not fit the 2015 model. If you are browsing used marketplaces for "Subaru wheels," you must verify the bolt pattern, as the older 5x100 wheels simply cannot be bolted onto the 2015 hub without dangerous and ill-advised adapters.
Analyzing Wheel Offset and Backspacing
The factory offset for all 2015 WRX rims is +55mm. Offset is the distance from the hub-mounting surface to the true centerline of the wheel. A positive offset means the mounting surface is tucked toward the street side of the wheel, pulling the rim further into the wheel well.
Subaru utilizes a high +55mm offset to maintain a specific "scrub radius"βthe distance between the steering axis and the center of the tire's contact patch. Maintaining a scrub radius close to the factory specification ensures that the car tracks straight under heavy braking and does not exhibit excessive "torque steer" or dartiness when encountering road imperfections.
When moving to aftermarket wheels, owners frequently choose a lower offset, such as +38mm or +35mm. While this pushes the wheels outward for a "flush" look with the fender, it is important to note that dropping the offset significantly can increase the load on the wheel bearings and slightly alter the steering geometry.
Center Bore and Hub-Centric Requirements
The center bore of the 2015 Subaru WRX is 56.1mm. This is the diameter of the hole in the center of the wheel that fits over the hub of the car. Subaru wheels are "hub-centric," meaning the hub of the car carries the weight of the vehicle and centers the wheel, while the lug nuts simply provide the clamping force to keep the wheel attached.
Many aftermarket wheels are "lug-centric" and come with a much larger center bore (often 73.1mm) to fit a variety of vehicles. To properly install these on a 2015 WRX, you should use hub-centric rings. These rings act as a spacer to fill the gap between the car's 56.1mm hub and the wheel's larger center bore. Failure to use these rings can lead to persistent high-speed vibrations, as the wheel may not be perfectly centered on the hub.
2015 Subaru WRX Technical Rim Specifications
The following table summarizes the essential measurements for both factory wheel options available for the 2015 model year.
| Specification | Base Trim | Premium / Limited Trims |
|---|---|---|
| Rim Diameter | 17 Inches | 18 Inches |
| Rim Width | 8.0 Inches | 8.5 Inches |
| Bolt Pattern | 5x114.3mm | 5x114.3mm |
| Offset | +55mm | +55mm |
| Center Bore | 56.1mm | 56.1mm |
| Lug Nut Thread | M12 x 1.25 | M12 x 1.25 |
| Stock Tire Size | 235/45R17 | 245/40R18 |
| Construction | Cast Aluminum Alloy | Cast Aluminum Alloy |
Aftermarket Fitment: Common Upgrades
The 2015 WRX chassis is famously wheel-friendly, with large wheel wells that can accommodate wider setups without major modifications. As of 2026, the aftermarket support for this chassis is mature, and the "community standard" fitments are well-documented.
The "Flush" Fitment
The most popular upgrade for the 2015 WRX is the 18 x 9.5-inch wheel with an offset between +35mm and +38mm. This setup pushes the wheel out significantly compared to the factory +55mm offset, bringing the edge of the rim nearly flush with the fender.
- Tire Pairing: Typically paired with a 255/35R18 or 265/35R18 tire.
- Modifications: With a +38mm offset and 255 tires, most owners do not need to roll their fenders unless the car is significantly lowered on coilovers. However, with a +35mm offset or 265-width tires, rear fender rolling may be required to prevent rubbing under compression.
Performance-Focused Lightness
Drivers prioritizing track performance often stick to the 17 x 9.0-inch or 18 x 9.0-inch sizes with a higher offset (around +45mm). By choosing a lighter-weight flow-formed or forged wheel in these sizes, owners can reduce unsprung weight. Reducing unsprung mass allows the suspension to react faster to road changes and improves acceleration and braking feel.
Winter Wheel Considerations
Given the WRX's popularity in snow-prone regions, many owners maintain a second set of "winter rims." When selecting rims for winter use, there are several strategic considerations:
- Downsizing: It is common to "downsize" from the 18-inch factory wheels to 17-inch rims for winter. The 17-inch rim allows for a narrower, taller tire (like a 215/50R17), which "cuts" through deep snow better than a wide 245-section tire.
- Clearance: The 2015 WRX has relatively large front brake calipers. While most 17-inch wheels fit, some extremely thick-barreled 16-inch wheels may not clear the front brakes. It is generally recommended to stick to 17 inches as the minimum diameter.
- Material: Steel wheels (often called "steelies") are a budget-friendly option for winter, but they are significantly heavier than alloy rims. If you value performance even in the winter, a cheap set of cast alloy 17x8 wheels is often the better choice.
The Impact of Rim Size on Handling and Performance
The choice between a 17-inch and 18-inch rim, or an even larger aftermarket option, significantly alters the driving dynamics of the 2015 WRX.
Rotational Inertia
A larger rim typically places more weight further from the center of rotation. This increases the wheel's rotational inertia, which can make the car feel slightly more sluggish during initial acceleration. Even if an 18-inch wheel weighs the same as a 17-inch wheel, the distribution of that weight matters.
Steering Precision
The 18.5-inch factory width provides a more stable foundation for the tire. When you turn the steering wheel, the tire's sidewall has less room to flex on a wider rim before the car begins to change direction. This results in the "point-and-shoot" feeling that WRX owners appreciate.
Braking and Heat Dissipation
Larger rim diameters provide more "air space" around the brake calipers. On the 2015 WRX, the front rotors are 12.4 inches. While they fit under 17-inch wheels, the 18-inch wheels provide better airflow, which can help dissipate heat during spirited driving or track sessions, reducing the risk of brake fade.
Frequently Asked Questions
Will 2015 WRX rims fit a 2015 STI?
Yes, they will physically bolt onto the hub because they share the 5x114.3 bolt pattern. However, you must be careful with the 17-inch Base WRX wheels. The 2015 STI features larger Brembo brake calipers that require specific spoke clearance. Most factory 17-inch WRX wheels will not clear the STI's front Brembo brakes.
Can I use 5x100 wheels with an adapter?
While 5x100 to 5x114.3 adapters exist, they are generally not recommended for a performance vehicle like the WRX. Adapters act as spacers (usually at least 15-25mm thick), which will drastically change your offset and put extra stress on the wheel studs and bearings. It is safer and more effective to buy wheels with the correct 5x114.3 bolt pattern.
Do I need to recalibrate my speedometer if I change rim sizes?
If you maintain the correct overall rolling diameter, you do not need to recalibrate. For example, the outer diameter of a 235/45R17 tire is nearly identical to a 245/40R18 tire. As long as your new rim and tire combination stays within 1-2% of the original factory diameter, your speedometer and AWD system will function correctly.
What is the torque specification for the lug nuts?
For the 2015 WRX, the factory recommended lug nut torque is 89 lb-ft (120 Nm). Always use a calibrated torque wrench and tighten the nuts in a "star" pattern to ensure even pressure across the hub surface.
Does the 2015 WRX have TPMS sensors in the rims?
Yes, the 2015 WRX uses a direct Tire Pressure Monitoring System (TPMS). There is a sensor inside each rim attached to the valve stem. If you buy new aftermarket rims, you will either need to move your old sensors to the new wheels or purchase a new set of sensors and have them programmed to the car's computer.
Final Recommendation for Owners
When selecting rims for a 2015 Subaru WRX, the most critical factors are the 5x114.3 bolt pattern and the 56.1mm center bore. If you are looking for the best balance of aesthetics and performance, an 18 x 9.5-inch wheel with a +38mm offset is the gold standard for this chassis. This setup provides a significantly improved stance without requiring aggressive body modifications or sacrificing the car's legendary handling. Always ensure you pair your rims with high-quality hub-centric rings if the center bore is larger than 56.1mm, and prioritize maintaining a consistent tire diameter across all four wheels to protect the Symmetrical All-Wheel Drive system.
