How to choose the right tire size

The right tire size is the one listed on your door placard and in your owner’s manual. Match that size, meet or exceed the OEM load index and speed rating guidance, then confirm with a licensed installer.

Last updated: October 8, 2026

By Smart Tire Picks Editorial Team

Sedan front tire and alloy wheel viewed from the side, the sidewall where size markings are molded
Illustrative AI generated photo.

Step 1 — Read the placard

Locate the tire information placard and note the OEM size and cold pressures. Cross-check the owner’s manual for your trim. Details: placard guide · placard checklist.

Step 2 — Decode the current sidewall

Compare what is on the car today with the placard. Previous owners may have installed a different size. Matching “what’s already on it” is not always correct.

Step 3 — Confirm load index and speed rating

Replacement tires should meet or exceed OEM load index and appropriate speed rating guidance for your vehicle. See load & speed explained.

Step 4 — Decide category for your climate

All-season, winter, and summer tires serve different temperature and surface conditions. Category overview: compare categories.

Step 5 — Plan install and TPMS

Budget for mounting, balancing, valve stems or TPMS service, and alignment checks when wear patterns suggest it. Improper install can create vibration or premature wear.

Optional plus-sizing

Larger wheels with lower-profile tires change ride, risk of wheel damage, and gearing feel. Treat plus-sizing as an engineering change — verify clearance, load capacity, and OEM guidance rather than copying a forum setup.

Sources

Outbound links to public references. We paraphrase; visit the source for full wording and updates.

  • NHTSA — Tires (TireWise) — Public guidance on tire inflation, the Tire and Loading Information label/placard, maintenance, and UTQG consumer grades.
  • USTMA, Replacing Tires — replace all four when possible; if replacing two, match size, load index and speed rating, and put the new pair on the rear axle; a single new tire should be paired with the deepest remaining tread and both put on the rear
  • NHTSA — Safety and savings ride on your tires — Overview of why tire maintenance and labeling matter for everyday drivers.

Check retailers

Purchase CTAs coming soon. Until then, compare availability at major tire retailers and confirm final specs with your installer.