Tires: Found treasure, coding system, tire size

Question
While using our metal detector in our backyard, we uncovered a tire. It looks old and is definitely rotted somewhat. We just purchased this 1.5 acre lot so we thought we'd have some fun digging up "TREASURES". These are the markings on the tire and I was wondering how old this tire might be.
SP-30610
31-30610
6.50-13-4PLY
Z062-481N
3-4061?(s)(3)(8) can't tell the last one is it s,3,or 8?
It is a Sears Allstate Supertred Nylon 4-Ply

Thanking you in advance for any help solving the mystery of my uncovered TREASURE!!!!

Debbie

Answer
Debbie,

Here's how to tell the age of a tire:

http://www.barrystiretech.com/dotcoding.html

But based on what you've told me, I'd guess this predates the use of this coding system, which went into place in the late 1960's.  The tire size would seem to indicate that as well.

There may be a way to tell the date of manufacture, but you'd have to find out who manufactured it and they would have to know what their system was over 50 years ago - not very likely.

So it's still a bit of a mystery.