Really old tire date codes

Anybody know how to read the date codes on really old tires? These are the Dunlops on my '83 Seca 900. Obviously, these are a bit past their freshness date, so I've already got new rubber on order. But I am curious how old these tires really are. I was reading up on date codes and I am guessing they must be pre-2000. If I am reading it right, maybe 1991? The back isn't near as cracked or worn as the front so maybe I am reading the wrong number if they both look like '91.

The bike has about 24K miles, so unlikely either is a factory tire. Judging by the wear and dates (if correct) this thing probably hasn't travelled much more than a few 1000 miles since '91.

 

I don't think those are date codes. I am not sure when date coding began but I do think the "M#" numbers on your tires are lot numbers or batch numbers. Date coding on the tires has not been around all that long. Modern date coding is 4 digits, the week and last 2 of the year the tire was built. Those with better info will be along shortly.

 

I think Fuller is right. The date code for tires manufactured before 2000 is a three-digit number that can be found on the sidewall of the tire:

• First two digits: The week of the year the tire was made

• Last digit: The last digit of the year the tire was made

• Triangle symbol: A small triangle on the sidewall indicates the tire was made in the 1990s

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For example, a date code of "346" could mean the tire was made in the 34th week of 1986 or 1996. It can be difficult to determine the exact year because the three-digit code isn't precise. To help, you can try to identify the decade the tire belongs to by looking at the brand, style, or sizing nomenclature. For example, if you're looking at an LR78-15 tire with a date code of "306", you might guess it was made in 1976 because P-metric sizing became more popular in the 1980s.

After 2000, a fourth digit was added to the date code so that the last two digits represent the year of manufacture.

Many automakers recommend replacing tires six years after the production date, regardless of tread life. Tire manufacturers like Continental and Michelin recommend replacing tires by the 10-year mark.

 

https://www.tires-easy.com/blog/tire-dot-date-code/

 

Thanks all. I didn't see anything with a triangle, but then my eyesight isn't so great anymore. One of the articles I read said it should have DOT nearby, which is why I thought one of these numbers.

Seems like about the only safe bet is that they're both pre-2000. Which I suppose is old enough.

When did the 80's become so long ago?