Tire Age -- Decoding Your Tires to Determine the Age
Tire age is a tricky subject at Coker Tire, because we manufacture NEW tires that look like old tires. There can be some confusion in regard to tire age, and that's why we wanted to put together this guide to decoding your tire and therefore determining the tire's age. The tire industry has some loose guidelines on tire age that call for tire replacement after 6 to 10 years of service. On a daily driver, you'll likely wear out the tread before the 6-10 year window, but on a collector vehicle, the tire could expire well before the tread is gone. Even if a car is stored inside and the tires pass a visual inspection (no cracks, dry-rot or other visible deterioration) we typically suggest replacement after 10 years if you plan on driving it.
So, what happens if you drive on a tire that is more than 10 years old? You could get lucky and the tire could last until the tread is worn down, or the tire could separate without warning. Even without noticeable defects, the tire could be susceptible to sudden delamination or separation due to the heat buildup from driving.
Usually, if you buy a set of tires for a collector vehicle, you will have a pretty good idea when that 10 years has passed. What if you buy a complete car, or buy a set of tires at a swap meet? You’ll need to determine the tire age before you can confidently drive on them. Luckily, decoding a tire and determining the tire's age is a pretty straightforward process, as a standardized 10-digit Tire Identification Number (often called a DOT number) was mandated by the United States Department of Transportation in 1971. Some manufacturers used date codes prior to 1971, but there wasn’t a standardized system, so each brand handled numbering differently.
This 1934 Plymouth hot rod was stored inside for decades. Its tires are from the early 1970's, and they look perfect. They hold air and show no signs of dry rot or deterioration. However, due to the age of the tires, they are not safe for driving. Luckily, we offer many tires that can perfectly replicate the vintage look of this period correct hot rod.
A confusing aspect of determining the age of a given tire is the fact that Coker Tire builds new tires in authentic molds. Using Firestone Wide Oval tires as an example, this tire product line was used on muscle cars from 1967 to 1974, and we have been producing the same tires since the 1980’s. The differences? Today’s U.S. D.O.T. requirements mandate that each tire has a unique Tire Identification Number on both sidewalls (inboard and outboard) of the tire, as well as safety information that is typically in fine print somewhere on the sidewall.
Otherwise, you’ll need to take a closer look at the Tire Identification Number to determine the date that they were produced. Tires built before 2000 featured a three-digit date code at the end of the Tire Identification Number. The first two digits of the date code tell you the week that the tires were built, and the last digit tells you the year. For example, a date code such as 306 would let you know that the tire was built in the 30th week of a year ending in 6. There could be confusion of whether the digit refers to 1976, 1986 or 1996, so let’s dig a little deeper.
Sometimes you can easily determine which decade the tire belongs in based on the sizing nomenclature, brand or style. Let’s say you’re looking at an LR78-15 tire, using the same 306 date code we mentioned earlier. Based on the alpha-numeric sizing nomenclature, it would be our best guess that the tire was manufactured in 1976, as the now standard P-metric sizing (ex. P215/75R15) became more popular in the 1980’s. You could also expect this tire to be missing the standardized safety warnings on the sidewall and any type of tread wear indicators, as those features were mandated later than 1976. That’s just one example but you can see how certain styles or sizes can be quickly identified by decade.
For tires built after the year 2000, the date code features four digits, and most Tire Identification Numbers are now 12 digits instead of 10. The first two digits of the date code are the week of production and the last two are the year of production. This helps to clear up the single-digit year confusion that existed before 2000. So, a tire with a date code of 4817 was built in the 48th week of 2017. The bottom line is if you’re restoring a car that will be driven, it needs tires that are less than 10 years old. At Coker Tire, we've made great effort to eliminate the excuse of "they don't make that tire anymore" by manufacturing original style bias ply tires, using new materials. Sure, there are small differences, like the Tire Identification Numbers and the mandatory safety information, but in terms of size, style and brand, we’ve covered a 100-year span of vehicles to keep you on the road safely without being forced to use generic modern tires. We have also stepped into the radial tire market with several brands and styles that mix the vintage look of bias ply tires with the smooth ride quality of a modern radial.
Most of the time, it's pretty obvious when a tire is too old to be used. This crusty bias ply tire is obviously past the point of no return, but it does serve as a decent roller, while the car is in the shop. We do suggest using "rollers" (aka junk tires) to roll around the shop while a car is being restored. Then, when it's time to drive, order your tires, so that you can get the most use out of them. If you buy them in 2018, but the car is in the shop until 2021, you're that many years closer to the tire's expiration date.
Whether you choose bias ply or radial tires for your collector vehicle, tire age is an important detail that should not be ignored. If you have a question about your tires, or need to replace your expired tires, feel free to call Coker Tire at 1-866-516-3215 and a tire expert will be glad to help! You can also reach us by email, or live chat on our website. Dry rot, and cracking are obvious signs that your tires are too old for use. However, expired tires may not always have such obvious visual deterioration. Be sure to check those date codes before you take off in your collector vehicle!
Determining tire age is easy! Each tire built after 1971 has a standardized Tire Identification Number (also known as a DOT number). The last four digits of the number (for tires built after 2000) give you the necessary information to determine the tire's age. This one was built in the 40th week of 2016.