Those colored stripes on a new tire are a factory code, and they mean nothing to buyers

Colored lines painted across the tread of a brand-new tire look like they must carry meaning: a performance grade, a size code, a warning. They do not. The stripes are factory production markings, put there for the people and machines that build tires, and they are meant to wear away within the first stretch of driving.

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A buyer comparing a blue line on one brand with a yellow line on another is comparing two codes that were never designed to be compared. What deserves attention sits elsewhere on the tire, in molded letters and numbers on the sidewall.

Production markers, not buyer information

Carscoops, in its explainer on the colored stripes, describes them as production markers that identify products or rubber compounds on the factory line, and states that their purpose is for the people and equipment making the tires rather than the person buying them. A bar of color applied during manufacturing is a quick visual cue, one that lets a worker or a machine tell one compound or product from another at a glance, without reading a label.

Each manufacturer runs its own system, so the colors have no universal meaning. A blue line at one company can signal something unrelated to a blue line at another, and in one patented process two colors together identify a single tread compound, which means reading a single stripe gives an incomplete picture. The markings belong to the manufacturer’s identification system. Nothing about the stripes is standardized across the industry, so no chart can translate them for a shopper.

Who applies the stripes and why they fade

The equipment comes from specialist suppliers. The German marking company REA, in its own description of color marking on rubber tires, presents the technology as a way to produce readable, permanent product markings that support quality assurance and traceability, using UV-curing pigmented inks to print text, logos and color lines on dark rubber. REA notes that its system applies color lines for coding or type identification on finished tires and that the tire industry took part in developing it. The company does not say what any particular color means.

The stripes are not designed to last. They rub off as the tire accumulates mileage, which is a feature rather than a fault: once the tire has left the factory and passed through the warehouse and the fitting bay, the code has done its work. Missing or faded stripes on a tire that has been driven say nothing about its condition, and a tire that still shows bright stripes is not newer, safer or better than one whose stripes have worn off. Only the date code can answer the question of age.

What to read on the sidewall instead

The marking that matters most to a buyer is the tire identification number. Under 49 CFR 574.5, a new tire carries a thirteen-symbol number made of a three-symbol plant code assigned by the National Highway Traffic Safety Administration, a six-symbol manufacturer’s code that can describe tire characteristics or identify the brand owner, and a four-digit date code. The first two digits of the date code give the week, with 01 as the first full calendar week, and the last two give the year, so a code ending 2125 means the 21st week of 2025.

That date is the number to check before paying for new tires. NHTSA’s tire safety guidance says the last four digits of the identification number show when the tire was made, notes that the number may appear on only one sidewall, so both should be checked, and adds that some manufacturers recommend replacing tires at six to ten years regardless of tread wear. A tire that has sat in a warehouse for two years has already used part of that window.

The rest of the useful information is also molded into the rubber. Federal Motor Vehicle Safety Standard No. 139 requires passenger tires to show the tire size designation, maximum load rating, maximum inflation pressure and DOT symbol, among other items. Carscoops adds the model name and the speed rating to the list of sidewall details worth reading, and these are the figures to match against the vehicle manufacturer’s recommendation for the car being fitted.

NHTSA’s tire guidance points to one more set of sidewall ratings on passenger tires sold in the United States, the Uniform Tire Quality Grading System, which reports treadwear, traction and temperature grades. Those grades are a better basis for comparing two tires than any stripe, because they are assigned under a common system rather than a private factory code, though they still deserve the usual scrutiny from a buyer who plans to compare models.

Directional tires add one more marking, an arrow on the sidewall showing the intended rotation direction, which is an instruction for the fitter. Colored stripes, by contrast, are an instruction for nobody who buys the tire.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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