Subaru Tire Size Calculator
Look up your Subaru's OEM tire size, then confirm an upgrade stays within Symmetrical AWD's safe diameter-match tolerance.
Quick Answer
2020–2024 Outback (Base/Premium) stock: 225/65R17 (28.50″, 35 PSI). Forester 2019–2024: 225/55R17 (27.76″, 36 PSI). Crosstrek 2018–2023: 225/60R17 (28.04″). Subaru Symmetrical AWD requires all four tires within ≤1% OD change — approximately 0.25–0.30″. Always replace all four tires simultaneously to protect the center differential.
| Model | Stock Size | OD / Pressure | Safe Upgrade |
|---|---|---|---|
| 2020–2024 Outback | 225/65R17 | 28.50″ / 35 PSI | 235/65R17 (+0.40″) |
| 2019–2024 Forester | 225/55R17 | 27.76″ / 36 PSI | 225/60R17 (+0.72″) |
| 2018–2023 Crosstrek | 225/60R17 | 28.04″ / 33 PSI | 225/65R17 (+0.99″) |
| 2022–2025 WRX Base | 235/45R18 | 26.34″ / 33 PSI | 245/45R18 (+0.45″) |
| 2022–2025 Outback Wilderness | 245/60R17 | 29.56″ / 35 PSI | AT stock — no upgrade needed |
| 2015–2021 STI | 245/35R19 | 26.75″ / 33 PSI | 255/35R19 (+0.39″) |
Symmetrical AWD safe limit: ≤1% OD difference ≈ 0.25–0.30″. Exceeding 2.5% risks center differential damage.
Common Subaru size swaps
How to Use This Calculator
- 1Select your Subaru model in OEM Lookup. Click your model name (Outback, Forester, Crosstrek, Impreza, Legacy, WRX, BRZ, Ascent, or Solterra). All OEM tire sizes by year, trim, rim size, OD, and recommended pressure appear instantly.
- 2Use Size Diff to check your swap. Enter your current stock tire code and proposed new size in the Size Diff tab. The calculator shows OD delta, AWD safety badge, sidewall comparison, and speedometer correction.
- 3Check the AWD Safety badge. Green = AWD Safe (≤1% OD delta). Yellow = Marginal (≤2.5%). Orange = Caution (≤4%). Red = Risk (>4%). Subaru's Symmetrical AWD requires all four tires within ~0.25–0.30" OD.
- 4Browse lifted tire sizes. Open the Lifted Sizes tab and select your model for verified fitment data: stock size, 1-inch lift, 2-inch lift, maximum AT size, max OD, and recommended wheel offset.
- 5Verify tire pressure by model. Open the Pressure tab to confirm cold-inflation PSI for your model. Forester: 36/35 PSI. Solterra EV: 38/38 PSI. Outback Wilderness: 35/35 PSI.
Subaru Symmetrical AWD — Tire Sizing Rules Explained
The 1% OD rule protects the viscous centre differential. Subaru's Symmetrical AWD uses a viscous centre differential that interprets any continuous wheel speed difference as wheel slip. A tire diameter mismatch of more than 1% (≈0.28″) applies continuous mechanical load through the differential — over thousands of miles this generates heat, accelerates wear, and can cause complete failure. Repair cost: $1,800–$4,500 at a dealership.
Always replace all four tires simultaneously. Even buying two identical tires from a new box can create a mismatch if the other two are worn — tread depth directly affects rolling circumference. The safe tread depth difference across all four tires is ≤1/4 inch (approximately 2/32\").
Wilderness edition is a factory-approved bigger tire. The Outback Wilderness ships with 245/60R17 all-terrain tires — significantly larger than the base 225/65R17. If you own a non-Wilderness Outback, the Wilderness tire package is not a bolt-on upgrade without also changing the suspension tune and speedometer calibration.
OEM tire size is on the door-jamb sticker, not the VIN. The VIN does not encode tire size in a user-readable way. The gold sticker on the driver's door pillar lists your exact OEM size, cold pressure front/rear, and load rating. If your current tires don't match the sticker, verify your actual rim diameter before ordering.