What is the DOT Code on a Tire Exactly

[Kirk M.]

I keep reading about Non-DOT tires. Does this mean that the tire simply doesn't have "DOT" or does it mean the tire doesn't have "DOT and all the numbers in the box as well"? Are the numbers the DOT Code? Do tires before 1968 have no "DOT" and no numbers in the box? Thanks.

Kirk

[William C.]

Re: What is the DOT Code on a Tire Exactly

As part of one of the Motor Vehicle Safety Standards laws, I believe beginning in 1968 all tire manufacturers were required to include a coded number on the tire to identify the manufacturer and date of manufacture. I believe there was an article on this in the "Restorer" magazine in the past few years or so. Specifications for what was carried varied over the years, but short form, that is the story of the DOT code for tires. Some manufacturers carried an ID stamp prior to the mandate for their own use, but some did not, thus the DOT directon.

[Jack H.]

Re: What is the DOT Code on a Tire Exactly

Yep, DOT rule making took effect 1/1/68 and each mfgr had to put a traceability code on the tires. Each mfgr 'made up' their own sequence(s) that would allow them to identify/report various aspects of a particular product to the DOT (when made, where made, Etc.).

It wasn't until 1Q of 1971 that DOT 'standardized' the code sequence (11-digit alpha numeric until the turn of the century and then a 12-digit code). The unusual issue is what tire mfgrs did with calendar year 1967 work in progress that didn't ship until after 1/1/68...

The handful of these 'exceptions' I've seen had the DOT code printed on paper stock and affixed to the sidewall with a clear plastic cover!

[Tom R.]

Re: What is the DOT Code on a Tire Exactly

I believe there was an article on this in the "Restorer" magazine in the past few years or so. .

Kirk & Bill

Over the past 18 months, the Restorer has published three tire articles. The article I wrote was published in the Winter 2008 edition and documented the use of DOT from 1971 and up. From 68- to 71 is sketchy and not well documented but you can tell that contributors to this board do have the knowledge that complete the pre 71 period. I understand that NCRS members have collected DOT information from this period (DOT codes) but have kept it proprietary.

[Kirk M.]

Re: What is the DOT Code on a Tire Exactly

Still need a direct answer to the question.

Is the DOT code the word "DOT" or the series of numbers in the rectangular box, or both? I have a tire that doesn't have "DOT" on it but has a series of numbers ending in 053, which I assume is 5th day of 1973 based on the tire. So, in essence this tire has a DOT code even if it is missing the actual abbreviation "DOT". Correct? Thanks.

[Jack H.]

Re: What is the DOT Code on a Tire Exactly

Gee, I thought the answer was pretty clear. The emboss (or for those handfull of work-in-progess tires when DOT rule making took effect) the label consists of "DOT" followed by an alpha-numeric sequence that contains that tire's source ID information.

From 1/1/68 to early 1971, the ID sequences were 'made up' and unique to each supplier. Later, the ID sequence was DOT standardized into an 11-character format. That changed to a 12-character format after the turn of the century.

What's unclear? Are you thinking that prior to DOT rule making the tire mfgrs did NOT have their own/unique source ID sequence(s)? Not true!

Most had some form of product ID for identification pupposes warranty verification, product recall identification, Etc. But, the information contained in these sequences would have been unique to a given mfgr and may not have contained some of the information field(s) that later DOT rulemaking mandated.

It's clear to me...I guess I don't see how your question hasn't been answered already.

[Kenneth H.]

Re: What is the DOT Code on a Tire Exactly

Kirk,

Below is a picture of the DOT marking on my 1968-70 original spare tire. I'm not exactly sure of the manufacture date, but it was after 1967 and before 1971, because of the nonstandard DOT number. If your tire does not have a DOT marking on it, it would have be manufactured prior to the mandate on 1/1/68.

[Duke W.]

Re: What is the DOT Code on a Tire Exactly

Still need a direct answer to the question.

Is the DOT code the word "DOT" or the series of numbers in the rectangular box, or both? I have a tire that doesn't have "DOT" on it but has a series of numbers ending in 053, which I assume is 5th day of 1973 based on the tire. So, in essence this tire has a DOT code even if it is missing the actual abbreviation "DOT". Correct? Thanks.

Assuming that 053 is the manufacturing date code it would indicate the fifth week of '73 (or '83 or '93).

If there is any doubt about the decade, it can generally be deciphered if you know the years the tire was available, and most tires' marketing life span is no more than 10 years, however, there are a few that were marketed for more than ten years, which can make the decade of manufacture foggy.

With the switch to a two digit year code in 2000, there will be no confusion.

If you have further questions, I suggest you post the make/model/size of the tire along with the complete string of characters.

Duke

[Terry M.]

Re: What is the DOT Code on a Tire Exactly

Kirk,

Below is a picture of the DOT marking on my 1968-70 original spare tire. I'm not exactly sure of the manufacture date, but it was after 1967 and before 1971, because of the nonstandard DOT number. If your tire does not have a DOT marking on it, it would have be manufactured prior to the mandate on 1/1/68.

What about this part of the tire marking?

[Kenneth H.]

Re: What is the DOT Code on a Tire Exactly

What about this part of the tire marking?

Kirk,

Does your number look like Terry's and mine (below)? Is it 11 digits? A picture would be good.

[Kirk M.]

Re: What is the DOT Code on a Tire Exactly

Check out my other post with pics titled "Does this tire look good as an original 67 spare?".

The tire is a Firestone Deluxe Champion with a 5/8" whitewall that I am trying to determine if is appropriate as a 1967 corvette original spare tire.

It definitely has a number embossed on it "000053AD". Hence my question/confusion on exactly what is a NON-DOT tire. This tire has a number embossed on it but does NOT have "DOT" anywhere on it. So, I have been trying to find out whether that means it was made after 1968, or whether it is possible that the number is a unique manufacturer's code from 1967. Any ideas?? Thoughts. Thanks.

Kirk

[Kirk M.]

Re: What is the DOT Code on a Tire Exactly

Ken and Terry,

My number looks like yours except the letters are at the end. What is the date on the two tires whose numbers you showed. Thanks.

Kirk

[Larry M.]

Re: What is the DOT Code on a Tire Exactly

Kirk:

I believe that you have a NON-Dot tire, correct for your car.

The eight digit embossed code is very likely the tire manufacturer's code for date, time, location, and/or batch number. This is what Jack Humphrey was saying earlier. Regardless of DOT rules or not, the tire manufacturer still needed a way to identify where/when his tires were produced in case of defects or liability.

Larry

[Kenneth T.]

Re: What is the DOT Code on a Tire Exactly

My '71 a GoodYear RWL.

[Kirk M.]

Re: What is the DOT Code on a Tire Exactly

All right, that is one vote for a correct tire. In the other post, I have one vote for it not being a correct tire. Anyone care to chime in with the swing vote!