OE placard size
Start with the vehicle's original tire size
The safest stock input is the tire size printed on the driver's door-jamb placard or owner's manual. Use that OE size as the baseline before checking a replacement against the ±3% rule, clearance, load index, and speed rating.
TL;DR
The most reliable original-equipment tire size is on the vehicle tire placard, usually on the driver's door edge or door post. NHTSA tells drivers to use that placard for the manufacturer's recommended tire size and cold inflation pressure, while the tire sidewall gives tire markings and maximum ratings, not the vehicle's OE recommendation (NHTSA tire safety, accessed June 26, 2026).
For a replacement-size comparison, enter the placard size first, then compare diameter, width, load index, speed rating, and physical clearance before buying.
Door placard
225/65R17
Baseline
Stock size first
Then check
Load, speed, clearance
Where should I enter my OE tire size?
Enter the size from the placard, not the worn tire if the car is used. TreadSize does not guess OE specs from a VIN or trim database yet. Enter the placard size you see on the vehicle, then compare any candidate replacement from that baseline.
1. How do I confirm OE?
Use the door placard or owner's manual. A used car may already have a non-original tire size installed.
2. What should I compare?
Keep diameter within the common ±3% tolerance, then review width, rim, offset, and clearance.
3. What still needs a fit check?
Before buying, confirm load rating, speed rating, brake clearance, full-lock steering, and suspension compression.
Which tire markings answer which question?
Use the placard for the vehicle baseline and the sidewall for tire-specific markings.
| Where to look | What it tells you | Source |
|---|---|---|
| Vehicle placard | Manufacturer-recommended tire size and cold inflation pressure for the vehicle. | NHTSA tire safety, accessed June 26, 2026 |
| Tire sidewall | Size marking, load/speed marking, DOT Tire Identification Number, and maximum tire ratings. | NHTSA tire safety, accessed June 26, 2026 |
| Owner's manual | Vehicle-specific tire and wheel guidance, including trims or staggered setups when applicable. | NHTSA tire safety, accessed June 26, 2026 |
How was this page verified?
Last updated and verified June 26, 2026. Method: TreadSize's comparison workflow was checked against NHTSA tire-safety guidance for placard location, tire sidewall markings, and cold inflation pressure. This page does not claim VIN-grade OE fitment data.
Frequently asked questions
Where is the original tire size on my car?
Start with the tire information placard on the driver's door edge or door post, then confirm in the owner's manual. NHTSA tells drivers to find the manufacturer's recommended tire size and pressure on that placard.
Can I use the tire size already mounted on a used car?
Use it only as a clue. A previous owner may have changed wheels or tires, so the door placard is the safer stock baseline before comparing replacement sizes.
Does the sidewall pressure replace the door-placard pressure?
No. The sidewall shows the tire's maximum pressure rating; the vehicle placard lists the vehicle manufacturer's recommended cold inflation pressure for that car.
Is matching size enough for a replacement tire?
No. You still need the correct load index, speed rating, wheel diameter, clearance, and inflation pressure for the vehicle.