I have a set of Toyo Open Country A/T’s (the first series, not the II’s), LT 305/55-20, starting to have some issues with them holding air. The DOT stamp on the sidewall reads “73B6”. I know the standard four digit stamp usually would tell you by the first two numbers the week the tires were manufactured and the last two numbers would be the year of. I don’t know what mine mean. Any help?

 

You are probably looking at the wrong number. See here -

https://www.tirebuyer.com/education/...-of-your-tires

 

I thought I was looking at the wrong number too. I went out and triple checked.. it says "DOT 73B6" on the outside wall of all the tires. I'll check the inside wall to see if there's a difference, however, we just had a storm and its sitting in a foot of snow and salt. Might be a while before I climb under...

 

https://www.toyotires.com/tires-101/reading-a-sidewall

They do show contact info. Good luck.

 

That's only a partial on the outside. You need to look at the inside.

 

Thank s for the help guys, so I checked the inside wall and finally got a good number, "3906". The tires were manufactured in the 39th week of 2006, so they are approximately 11.5 years old even though I've only had them for about 9 of those years. However, I've only put a little more than 40,000 miles on them without any issues, the truck has 54k miles on a 2007. Still plenty of tread left, time for new tires? What do you think?

It's my daily driver/family vehicle, however, I have a company car so it doesn't get driven a lot (hence the low mileage). There's a date that the tires were manufactured, is there an expiration date on tires too?

 

I'd wear them out but I'm cheap.

 

Replace them. Industry standard is 10 years, some manufacturers recommend 6 years.

 

Well I finally found the slow leak, both drivers side tires were leaking from the weights on the inside of the rim. What are the chances of that, both at the same time?

Anyways, I think after I throw a bandaid on these for now just to get me through the winter and maybe the summer I’ll start looking for new ones. Thanks for the help guys!