Everything a manufacturer legally has to tell you about a tire is molded into its sidewall. Size, load capacity, speed capability, construction type, manufacture date, tread wear expectations — it's all there, compressed into codes that nobody ever explains. Once you can read them, you can verify a shop sold you the right tire, spot a tire that's aged out even though the tread looks fine, and understand why West Texas is harder on tires than almost anywhere in the country.
Here's the sidewall, decoded piece by piece, with the Lubbock-specific implications called out.
The Main Size Code — P225/60R17 98H
This is the big one, and it breaks into six separate pieces of information:
- P — Tire type. "P" means P-metric, a passenger vehicle tire. "LT" means Light Truck, built with heavier construction and stiffer sidewalls for higher loads — extremely common on the pickups that dominate West Texas roads. No letter at all indicates a Euro-metric tire, similar to P-metric but rated slightly differently for load.
- 225 — Section width. The width of the tire in millimeters, measured sidewall to sidewall at its widest point. A 225 is 225mm wide, roughly 8.9 inches.
- 60 — Aspect ratio. The sidewall height as a percentage of the section width. A 60 means the sidewall height is 60% of 225mm, or about 135mm. Lower numbers mean shorter, stiffer sidewalls; higher numbers mean taller sidewalls with more cushion — which matters on Lubbock's caliche roads and rough railroad crossings.
- R — Construction. "R" is radial, which is essentially every modern passenger tire. You'll see "D" (diagonal/bias-ply) on some trailer tires — relevant if you're hauling stock or equipment.
- 17 — Wheel diameter. The diameter of the wheel the tire fits, in inches. This one is absolute — a 17-inch tire does not go on an 18-inch wheel, ever.
- 98 — Load index. A coded number that maps to a maximum weight per tire. 98 corresponds to 1,653 pounds. Never go below your vehicle's specified load index — it's a safety limit, not a suggestion.
- H — Speed rating. A letter that maps to a maximum sustained speed. H is 130 mph. Common ratings: T (118), H (130), V (149), W (168).
Why Load Index Matters More on West Texas Trucks: If you're running a pickup that hauls equipment, tows a trailer, or carries a load through farm country, your load index isn't a theoretical number. A tire operating near its load ceiling generates significantly more internal heat — and in Lubbock's summer, that's heat stacked on top of 150°F pavement. This is where undersized tires fail.
The DOT Code — How Old Are Your Tires Really?
Somewhere on the sidewall you'll find "DOT" followed by a string of characters. Most of it is plant and batch data. The part that matters is the last four digits.
Those four digits are the manufacture date: the first two are the week of the year, the last two are the year. So 3624 means the tire was built in the 36th week of 2024 — early September 2024.
This is the single most important number on the sidewall for Lubbock drivers, and here's why. Rubber degrades from UV exposure, ozone, and heat cycling — regardless of how many miles you put on it. West Texas delivers all three in extreme measure. Relentless sun, minimal shade, and daily summer temperature swings that expand and contract the rubber over and over. A tire in Lubbock ages faster than the same tire in a moderate climate, full stop.
- Under 5 years: normal service, no age concern.
- 5 to 6 years: inspect annually. Look closely for fine cracking in the sidewall — "weather checking" — which shows up earlier here than the national averages suggest.
- 6+ years: most manufacturers recommend replacement regardless of tread depth. In West Texas, treat this as a real deadline rather than a conservative guideline.
- 10 years: universally considered the absolute maximum, no exceptions.
This is also the number to check when buying. "New" tires that sat in a warehouse for three years are three years into their service life already. Always ask, and verify it yourself on the sidewall before installation.
Not Sure What's on Your Sidewall?
Bring it in — Lubbock Tire Shop will read your sidewall codes, check your date codes, and tell you exactly where your tires stand. No charge for the inspection.
Speed Rating — It's Really a Heat Rating
Most drivers dismiss the speed rating because they don't plan to drive 130 mph. That's the wrong way to think about it.
A speed rating certifies that a tire can dissipate the heat generated at that sustained speed without structural failure. It's a measure of how well the tire construction sheds heat — and heat is the enemy in West Texas.
Consider what a Lubbock driver actually does: 75 to 80 mph on US-87 toward Midland or I-27 toward Amarillo, for an hour or more at a stretch, on pavement that's radiating 150°F+ back into the tire, with ambient air over 100°F. That combination puts a tire much closer to its thermal limits than the same speed would in a cooler climate.
Never install a tire with a lower speed rating than your vehicle specifies. And if you're choosing between two otherwise comparable tires, the higher speed rating generally indicates more robust heat management — which in Lubbock is worth something real. Learn more about how West Texas heat affects tire pressure and performance.
UTQG — Treadwear, Traction, and Temperature
You'll find three more ratings grouped together, part of the Uniform Tire Quality Grading system:
- Treadwear (a number like 400 or 600). A relative durability score — a 600 tire should theoretically last twice as long as a 300. The catch: it's self-reported by each manufacturer against their own reference tire, so it's only useful for comparing tires within a single brand. Don't compare a Michelin 500 to a Goodyear 500 and assume they're equivalent.
- Traction (AA, A, B, or C). Wet-braking performance. AA is best. West Texas doesn't get much rain — but when it does, it comes hard and fast onto roads carrying months of oil buildup, which is exactly when wet traction matters most.
- Temperature (A, B, or C). Heat resistance at sustained speed. A is best. Of all three UTQG grades, this is the one Lubbock drivers should weight most heavily. A "C" rated tire meets the federal minimum and nothing more — in this climate, hold out for an A.
Max Load and Max Pressure — Not Your Target Pressure
Near the rim edge you'll find something like "MAX LOAD 1653 LBS AT 44 PSI MAX PRESS." This is one of the most commonly misread markings on a tire.
That 44 PSI is the maximum pressure the tire can safely hold — it is not the pressure you should inflate to. Your correct inflation pressure comes from the placard in your driver's door jamb, set by the vehicle manufacturer for your specific car. That number is usually between 30 and 36 PSI.
Inflating to the sidewall max gives you a harsh ride, center-worn tread, and a reduced contact patch. Always use the door jamb number. And in Lubbock, remember that pressure moves roughly 1 PSI for every 10°F change — check monthly, always in the morning before driving, when the tires are cold and the reading is honest. Learn more about how TPMS works and what triggers the warning light.
Directional Arrows and Rotation Markings
Some tires have an arrow and the word "ROTATION" on the sidewall. These are directional tires — the tread is designed to work in one direction only, typically for water evacuation. They can only be rotated front-to-back on the same side of the vehicle, never crossed.
Others are marked "OUTSIDE" and "INSIDE" — asymmetric tires with different tread patterns across the face. These must be mounted with the correct face outward.
If you have either type, it changes your rotation pattern — and rotation matters more in West Texas heat than most places, since heat accelerates any uneven wear that develops. Learn more about tire rotation schedules for Lubbock drivers.