How to find your correct tire size

We need your tire size before we can source or install anything. There are two places to find it, and they should usually agree.

Check your door jamb sticker first

Open the driver's door and look at the jamb, the part of the door frame you cannot see when the door is closed. Most vehicles carry a placard here from the manufacturer listing the recommended tire size, along with the recommended cold tire pressure. This is the size the vehicle was designed around, and it is the one to use unless you have deliberately fitted a different size for a reason you understand, such as a plus-size wheel upgrade.

Reading the code on the tire's own sidewall

The tire currently on your car also carries its size, stamped into the sidewall as a string like P215/65R15 95H. Reading it left to right:

• P (or nothing, or LT): the tire type. P means passenger vehicle; LT means light truck; no letter is common on European-sized tires.
• 215: the tire's width in millimeters, measured sidewall to sidewall.
• 65: the aspect ratio, meaning the sidewall height as a percentage of the width. Lower numbers mean a shorter sidewall.
• R: construction type. R means radial, which is nearly universal on modern tires.
• 15: the wheel diameter in inches that the tire is built to fit.
• 95: the load index, a coded number for how much weight the tire is rated to carry per tire.
• H: the speed rating, a coded letter for the tire's maximum sustained speed capability.

This is a standardized format used across tire manufacturers, so once you can read one sidewall you can read any tire's.

What if the door placard and the current tire do not match

This happens when a previous owner or shop fitted a different size than the vehicle shipped with. Tell us both numbers when you request service; we will ask which one you want to keep going forward, since matching the vehicle's designed size is usually the safer default unless you have a specific reason for the other size.

What we ask for, and why

We ask for the full size string, not just the wheel diameter, because the width, aspect ratio, load index, and speed rating all affect fitment, handling, and whether the tire is even legal for your vehicle's weight and speed capability. A tire with a lower load index or speed rating than your vehicle calls for is not a safe substitute even if the diameter matches.

What we do not do

We do not guess your tire size from your vehicle's year, make, and model alone, because the same model can ship with different factory sizes or have been changed since. We always confirm against the placard or sidewall.

Questions people ask {#faq}

• What if I cannot find the door jamb sticker? Some vehicles place it in the glovebox door or fuel filler door instead; your owner's manual will say where.
• Can I just tell you the wheel size, like "17 inch"? No, we need the full code; wheel diameter alone does not tell us the width or load rating.
• What if my spare is a different size than my regular tires? That is common and expected, especially with compact spares; tell us which tire you are replacing.
• Does the size ever change with seasonal tires? It can if you run a different size in winter; give us the size of the set you want installed.

Why book this way

• Your price online in minutes. No callback, no estimate visit, no waiting for someone to get back to you. Typically the quickest way to book this service.
• One all-in price before any contact. Of the national mobile tire services we read, only Tire Rack publishes an installation price; the others quote after you contact them or reach checkout (read 2026-09-16 and 2026-09-17).
• One point of contact from your request to the finished job. We work with a local partner and answer for the result.
• You pay only after the price and your booking are confirmed.

Get my price

Once you have your size from the door placard or sidewall, request service and we will confirm fitment and a price before you commit. Checkout is a labeled preview until card payments are enabled.

Sources

This guide describes the standardized tire sidewall notation and manufacturer door-placard convention used industry-wide; both are verifiable directly on the reader's own vehicle and tires, so no third-party statistic or dated public source applies here.