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, wet-traction performance — it's all there, compressed into codes 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 choose a tire that actually performs when I-95 turns into a sheet of water in about ninety seconds.
Here's the sidewall, decoded piece by piece, with the Jacksonville-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 for higher loads — common on the trucks and larger SUVs around Northeast Florida. 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 over Jacksonville's expansion joints and rougher older road surfaces.
- 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 pulling a boat to the coast.
- 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 mapping 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 mapping to a maximum sustained speed. H is 130 mph. Common ratings: T (118), H (130), V (149), W (168). This is about sustained heat tolerance, not how fast you intend to drive.
Traction Grade — The One That Matters Most in Jacksonville
Among the three UTQG grades on your sidewall, traction is the one Northeast Florida drivers should care about most, and it's worth pulling out ahead of the others.
The traction grade — AA, A, B, or C — measures straight-line wet braking on both asphalt and concrete test surfaces. AA is the best available; C is the federal minimum, meaning a C-rated tire is legal and essentially nothing more.
Now consider Jacksonville's reality: over 100 thunderstorm days a year, storms that dump hard and fast with almost no warning, and a road network where those storms land on I-95, I-10, and the Buckman and Dames Point bridges at 65 to 70 mph. Water sheets across the pavement. The first ten minutes of a Florida downpour are the most dangerous, when accumulated oil lifts off the road surface.
That is precisely the scenario the traction grade measures. Look for AA, or A at minimum. The price difference between a B-rated and an A-rated tire is usually modest; the difference in stopping distance on wet pavement is not.
Traction Grade Is Not Hydroplaning Resistance: The two are related but distinct. Traction grade measures wet braking; hydroplaning resistance depends heavily on tread depth and groove design. A tire can carry an AA traction grade and still hydroplane if the tread is worn down. In Jacksonville, you need both — a high traction grade and adequate remaining tread. Learn more about when to replace your tires.
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.
Florida is genuinely one of the harshest tire-aging environments in the country, and it's a three-part attack. Intense year-round UV breaks down rubber compounds. Sustained heat accelerates the chemical degradation. And Jacksonville's persistent humidity — routinely 80 to 90 percent through the summer — works on the rubber in ways drier heat doesn't. Add salt air near the coast and Ponte Vedra, and the effect compounds further.
- Under 5 years: normal service, no age concern.
- 5 to 6 years: inspect annually. Look for fine cracking in the sidewall — "weather checking" — which appears earlier in Florida than national averages predict.
- 6+ years: most manufacturers recommend replacement regardless of tread depth. In Northeast Florida, treat this as a firm deadline rather than a cautious suggestion.
- 10 years: universally considered the absolute maximum, no exceptions.
This applies with particular force to vehicles that sit — second cars, boats on trailers, RVs parked between trips. A tire doesn't need miles to age out in Florida; it just needs time in the sun. Learn more about how Florida heat and humidity affect your tires.
Not Sure What's on Your Sidewall?
Bring it in — Tire Shop Jacksonville will read your sidewall codes, check your date codes, and tell you exactly where your tires stand. No charge for the inspection.
The Rest of UTQG — Treadwear and Temperature
- 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 equivalence.
- Temperature (A, B, or C). Heat resistance at sustained speed. A is best. Given Florida's ambient heat and the sustained highway speeds on I-95 and I-10, an A grade is worth prioritizing here too — though for Jacksonville drivers, traction still edges it out as the top priority.
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.
Overinflating to the sidewall max is actively counterproductive in Jacksonville. It rounds the contact patch, reduces the tread area touching the road, and makes hydroplaning more likely in exactly the wet conditions you're trying to handle. Always use the door jamb number. Check monthly, in the morning before driving, when the tires are cold. 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, and in most cases that design is specifically about evacuating water out from under the contact patch. That makes directional tread patterns genuinely valuable in Florida.
The trade-off is rotation flexibility: directional tires can only move front-to-back on the same side of the vehicle, never crossed. Others are marked "OUTSIDE" and "INSIDE" — asymmetric tires that must be mounted with the correct face outward.
If a shop rotates directional tires side-to-side, they've made a real mistake and compromised the water evacuation the tread was designed for. Learn more about tire rotation schedules for Jacksonville drivers.