Subaru Tire Size Calculator

Subaru Tire Size by Year (2010–2025) — Base Trim Reference

Stock base-trim tire sizes for the four most-searched Subaru models. Verify your specific trim with the OEM Lookup tab above — higher trims often use a larger wheel diameter.

Base trim only. Higher trims (Limited, Touring, XT, Sport, Wilderness, STI) use larger diameters — see the full OEM Lookup tab. "—" indicates model not yet available that year.

Subaru Tire Size Formulas

How to Use This Calculator

1. 1

   Select 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.

2. 2

   Use Size Diff to check your swap

   Enter your current (stock) tire code and your proposed new size in the Size Diff tab. Click Calculate Difference to see OD delta, AWD safety badge, sidewall comparison, and speedometer correction table.

3. 3

   Check 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 to protect the center differential.

4. 4

   Browse lifted tire sizes

   Open the Lifted Sizes tab and select your model for verified RalliTEK fitment data: stock size, 1-inch lift, 2-inch lift, maximum AT size, max OD, and recommended wheel offset.

5. 5

   Verify tire pressure by model

   Open the Pressure tab to confirm cold-inflation PSI for your model. Note special values: Forester is 36/35 PSI, Solterra EV is 38/38 PSI, Outback Wilderness is 35/35 PSI.

6. 6

   Use the full Size Chart for a complete overview

   The Size Chart tab lists all 44 OEM fitments across all models and years. Filter by model name or expand to show all rows. Use the sticky-header table to cross-reference years.

Why Subaru AWD Has a Strict Tire Size Tolerance

Subaru's Symmetrical All-Wheel Drive system uses a viscous centre differential (or active torque vectoring on newer models) that expects all four wheels to rotate at near-identical speeds. When two tires have different overall diameters, the differential detects a continuous "speed mismatch" and interprets it as one axle slipping. The mechanical response is to partially lock up — which, sustained over thousands of miles, generates heat, accelerates differential wear, and can eventually cause complete centre differential failure. The repair cost ranges from $1,800–$4,500 at a dealership. The safe OD difference threshold Subaru recommends is within 1/4 of an inch (≈0.25–0.30 in) across all four tires — equivalent to roughly 1.0% OD difference. This is why replacing all four tires simultaneously is mandatory on Subaru AWD vehicles whenever changing size.

How to Find Your Subaru Tire Size by VIN

Every Subaru's exact OEM tire size is encoded in the VIN (Vehicle Identification Number) and stamped on the door-jamb sticker on the driver's door pillar. The sticker shows the OEM size, recommended inflation pressure (front and rear), and maximum load rating for your specific production build. If you've purchased a used Subaru and the tires don't match the sticker, verify the actual rim diameter with a tape measure before ordering — rim diameters on Subaru changed significantly across generations (e.g. Crosstrek went from 16″ to 17″ in 2018, then 18″ in 2024). The safest method to confirm your exact size is: (1) check the door-jamb sticker, (2) look at the sidewall of the current tires, (3) cross-reference with the OEM Lookup table above using your model and year.