What Tire Size Fits a Subaru Outback?

📋 The short answer

The number you actually want is printed on a placard inside your driver-side door jamb. That label is the single source of truth for your specific car, because Subaru changed wheel packages across model years and option groups. The two sizes above cover the vast majority of Outbacks built from 2010 through 2025, but the placard wins any argument.

If you only remember one thing: the wheel diameter (the 17 or the 18) is fixed by the wheel bolted to your car. You cannot put a 225/65R17 tire on an 18-inch wheel. You can swap a whole wheel-and-tire set between trims, but never a lone tire onto the wrong size wheel.

🚚 Outback tire size by year and trim

This table covers the common factory fitments. Trim names shifted over the years, but the wheel split has stayed consistent: smaller wheels and taller sidewalls on value trims, larger wheels on premium trims.

*The Outback Wilderness is the exception. It ships from the factory with a taller, more aggressive size (around 225/65R17 on a unique wheel with extra all-terrain clearance) and a higher ride height, so treat it as its own spec and check the door placard.

🔍 How to read 225/65R17

Decoding the size takes ten seconds once you know the pattern. Using 225/65R17 as the example:

• 225 is the tread width in millimeters.
• 65 is the aspect ratio, meaning the sidewall height is 65 percent of the width. A higher number means a taller, cushier sidewall.
• R means radial construction, which every modern passenger tire uses.
• 17 is the wheel diameter in inches.

You will also see a load index and speed rating, like 102H. For a Subaru Outback you want to match or exceed the factory load index so the tire can carry the vehicle, passengers, and cargo safely. Going below it is the one substitution you should never make.

📏 The biggest tire you can fit

This is where most owners actually land on this page. The honest answer depends on whether your Outback is stock or lifted.

Stock, no lift

On an unlifted Outback, the safe upsize ceiling is roughly a 3 percent increase in overall diameter before you risk rubbing at full steering lock or under suspension compression. In practice that means:

• 245/65R17 adds about an inch of diameter and a bit of width. It is the most popular no-lift upsize and clears on most Gen 5 and Gen 6 cars, though some owners report light rubbing on the plastic fender liner at full lock.
• 225/70R17 is a milder, taller-only option that keeps the stock width and bumps diameter modestly.
• A factory-size 225/65R17 in a true all-terrain tread is the zero-risk choice if you want grip without geometry changes.

With a small lift

A half-inch to one-inch lift kit opens up 30-inch all-terrain tires and sizes like 245/65R17 with comfortable clearance. Beyond about 30 inches you start fighting the constant-velocity axle angles and inner fender plastics, and you may trigger driveline vibration. If you feel new vibration after an upsize, that is worth diagnosing before it becomes a worn axle. Our guide on vibration at highway speed walks through the usual culprits.

One critical Subaru-specific warning: oversized or mismatched tires can confuse the all-wheel-drive system. If you start seeing AWD or traction warnings after a tire change, check for a stored code first. A C0035 wheel speed sensor code often shows up when one corner is spinning a different circumference than the rest.

⚠️ Common mistakes to avoid

• Mixing tire sizes or brands. Subaru's symmetrical all-wheel drive is unusually sensitive to circumference differences. All four tires should match in brand, size, and tread depth within about 2/32 inch. A larger mismatch can bind the center differential and lead to expensive driveline wear.
• Replacing only one or two tires. If three of your tires are worn and you replace one, the new tire's larger circumference creates the same mismatch problem. Many shops will shave a new tire to match, or you replace in matched pairs at minimum.
• Ignoring the load index. A passenger-rated tire below the factory load index can overheat under a loaded Outback. Match or exceed it.
• Assuming 17 and 18 are interchangeable tires. They are interchangeable wheel-and-tire packages, not interchangeable tires. The wheel sets the diameter.
• Skipping the placard. Aftermarket or previous-owner wheels mean your car may not wear the size the original window sticker listed. Trust the door jamb label and the molding on the sidewall.

🧮 How to pick the right size

Use this quick decision path before you buy:

1. Open the driver door and read the placard. That is your factory size, full stop.
2. Decide your goal. Quiet highway comfort points you to a touring all-season in the factory size. Trail and snow capability points you to an all-terrain, possibly upsized.
3. Choose stock or upsize. No lift means cap your upsize near 245/65R17 or a 3 percent diameter bump. Want bigger? Budget for a small lift.
4. Match all four. Always replace as a set on an Outback, or as close to it as your tread depths allow.
5. Verify clearance before highway use. Turn the wheel lock to lock in a parking lot and listen for rubbing, then check again loaded.

If you are sizing tires because something feels off, like uneven wear or a pull, that may be an alignment or suspension issue rather than the tires themselves. Our tire wear inspection guide shows what each wear pattern means, and the quote checker can tell you whether the price a shop quoted for new tires and an alignment is fair.

❓ Frequently asked questions

✅ TL;DR

Your Subaru Outback runs 225/65R17 on lower trims and 225/60R18 on higher trims, with both sized to about 28.5 inches overall. The placard in your driver door jamb is the definitive answer for your car. Stock, you can upsize to roughly 245/65R17 before clearance becomes a problem; bigger than that needs a small lift. Always replace all four as a matched set to protect the all-wheel-drive system.