What Size Spare Tire Cover Do I Need? (Complete Sizing Guide)

What Size Spare Tire Cover Do I Need?

This is the number one question we get — and the good news is the answer is printed right on your spare tire. You do not need to measure anything. You just need to know where to look.

Step 1: Find the Code on Your Tire Sidewall

Look at the side of your spare tire. You will see a string of numbers and letters that looks something like this:

• 265/70R17
• 245/75R16
• LT285/70R17
• P235/65R18

That code tells you everything. Here is how to read it:

Step 2: Decode the Numbers

Using 265/70R17 as an example:

• 265 — The width of the tire in millimetres
• 70 — The aspect ratio (sidewall height as a percentage of width)
• R — Radial construction
• 17 — The wheel rim diameter in inches

To find the overall diameter of your tire — which is what spare tire cover sizes are based on — enter the code into our sizing tool and we will calculate it for you instantly.

Common Tire Sizes and the Cover Diameter You Need

• 215/75R15 → 27" cover
• 235/75R15 → 28" cover
• 245/75R16 → 29" cover
• 265/70R16 → 29–30" cover
• 265/70R17 → 30" cover
• 285/70R17 → 32" cover
• 285/75R16 → 32" cover
• 315/70R17 → 34" cover
• 37x12.5R17 → 37" cover

What Vehicles Take Which Sizes?

• Jeep Wrangler JL/JK (stock) — 30" to 32"
• Jeep Wrangler (lifted) — 33" to 37"
• Ford Bronco (stock) — 30" to 32"
• Toyota 4Runner — 30" to 32"
• Ford F-150 / Chevy Silverado — 30" to 32"
• SUVs (RAV4, CR-V, Explorer) — 27" to 29"
• RVs and motorhomes — 27" to 32" depending on class

When in Doubt, Go With the Code

The code on your sidewall gives you the exact size. A cover that is even half an inch too small will not snap on properly, and one that is too large will sag and blow off at highway speeds.

Frequently Asked Questions

Can I measure the tire instead of reading the code?
You can, but it is less accurate. The sidewall code accounts for the true inflated diameter, which is what matters for fit.

My tire has LT or P at the start — does that affect sizing?
No. Those prefixes do not affect the diameter calculation for tire cover sizing.

I have a full-size spare vs. a donut spare — does it matter?
Yes. Spare tire covers are designed for full-size spares only. Compact donut spares are too small and do not typically mount on the exterior of the vehicle.