Tire Tech – How To Read Manufacture Dates
In our past Tire Tech – How To Read A Tire Sidewall article we covered UTQG ratings, tire sizing and load/speed ratings. Those are the basic requirements for understanding what kind of tire you’re holding in your hands. But, before you head out and laugh in the face of the tire shop help, there’s more. Much less publicized is the manufacturing date stamped on to the sidewall of every tire.
Imagine this scenario – with all sorts of numbers and letters bouncing around in your head, you head out to buy some new tires for your rubber roaster. You know what size, brand and, thanks to us (no applause necessary, really – Ed.), model you want. It’s got the right stickiness, low treadwear rating and high speed/load index. Now it just comes down to price.
Going Out Of Business Tire Shop (GOOB) has the tire for $100/each. Everything Must Go Tire Shop (EMG) has the tire for $90/each. Since they’re the same spec, you’d just get whatever was cheapest, right? You shouldn’t.
What if we told you that EMG’s tire was actually three years older than GOOB’s? Doesn’t sound like such a good deal any more, huh? That $10 savings means using a tire that has sat on a rack gathering dust and hardening. It’s even worse if they’re r-compound racing tires. We’ve seen pro racing teams lose more than a second per lap from using race tires that are a little over a year old. When it comes to going fast, fresh rubber counts.
The way to check that you’re getting the freshest tires is to check the manufacturing date. Many tires shops won’t mention this to you. Hell, some don’t even know themselves. It’s actually quite simple. Printed on the sidewall of almost every tire is a four-digit code inside an ellipse. The first two digits are the production week of the tire; the second two digits are the production year of the tire.
Example: Kumho V710 racing slick tire
Manufacture code: 3705 = September 2005
37th (week) = September
05 (year) = 2005
In our example, we use a Kumho V710 racing tire with a code of 3705. This means that the tire was made in the 37th week (September) of 2005. Similarly, a code of 0310 would mean that the tire was made in the 3rd week (January) of 2010. With 52 weeks in a year, figuring out the tire’s manufacture date is easy.
And yes, our Kumho is a very old tire by today’s standards. If you remember correctly, we blew one of these up at the track on Project Evo IX.
Next time you go buy a set of tires, arm yourself with OR knowledge. Ask for the tire manufacture date and aim to buy performance tires that are at least less than half a year old. If the shop doesn’t know the manufacture date or how to check, take a look for yourself. Wait for a different shipment if it comes down to it and you have the time. And, if your shop doesn’t move enough of the tire you want and can’t get anything new enough, maybe try buying elsewhere.
Just ran across this. Very easy to understand but how about a follow-up with more detail on tire construction? That ripped slick looks wicked…
Those tires suck. Did that happen because they were old or just couldn’t take the heat?