12/70 original spare tire - DOT 149

[inline6]

I have been searching for an original tire for my 6/1971 240z which I am restoring.  I have read through all the threads I can find about what tires the 240z's came with originally (Bridgestone or Toyo).  I knew my other 240z (track day car) still had the original spare tire in it, so I took a fresh look at it.  I was surprised to see that the date code is 149 (fourteenth week of 1969).  That is a lot earlier than I expected for the car given its 12/70 door tag date.  

It seems unlikely that it would have been swapped out for an earlier tire at some point.   Anyone else see that kind of wide date range difference comparing your original spare tire and the manufacture month of your car?  

 

 

 

 

 

Edited December 17, 2023 by inline6

[crayZlair]

"Just In Time" manufacturing was just starting to ramp up in the early 70's, so it's possible that it didn't apply to tires, especially spares, at the time.

[CanTechZ]

The DOT standardized "Tire Identification Number" system did not come into affect until January 26th 1971. Prior to that tire manufacturers used there own systems for date codes. After reading this topic I pulled the original spare from my 7/70 to see what I could learn. Mine is a 175SR14 Bridgestone Superspeed Radial-20. It still has 7/32" of tread left. There are markings that read "K7001" to the left of "DOT" and R20N to the right. I also discovered on more thing I had not noticed before. On the reverse side of the tire there is one more marking in addition to the ones on the outer side. It reads "KLILX" and was created by a mold that could be changed for each run of tires. You can see impressions of the screw heads that would hold the tag in addition to the date code numbers. All of the other markings are part of the permanent tire mold. I now believe that this is the date code. I have no idea how to decipher it. I was thinking roman numerals but that read 51st week 1960. @kats any thoughts?

The last picture is of a modern Bridgestone tire that was last on my car before I started my resto. It uses the modern DOT system which since 2000 uses a 4 digit date code (0403 = 4th week 2003), but you can see that this portion of the DOT number is changeable.

Here are a few pictures showing condition and markings.

edit: added the pic showing the "KLILX" marking.

 

 

Edited December 17, 2023 by CanTechZ
Added picture

[CanTechZ]

Here are a couple of spare tire pics from a BaT auction of an 8/71 that did not meet reserve in 2022. The spare is a 175HR14 RD-150 Bridgestone date coded 30th week 1971.

https://bringatrailer.com/listing/1971-datsun-240z-205/

[inline6]

2 hours ago, CanTechZ said:

The DOT standardized "Tire Identification Number" system did not come into affect until January 26th 1971. Prior to that tire manufacturers used there own systems for date codes.

Thanks for all of that info. 

So, what can we conclude about my Toyo Z radial spare tire?  Is it possible that Toyo was using the 3 digit dating system before it became standardized?  Or, is my tire from the 14th week of... 1979?

 

[CanTechZ]

8 minutes ago, inline6 said:

Thanks for all of that info. 

So, what can we conclude about my Toyo Z radial spare tire?  Is it possible that Toyo was using the 3 digit dating system before it became standardized?  Or, is my tire from the 14th week of... 1979?

 

I would  think that since your tire is marked 175SR14 it must be early 70's latest. By 1979 it would have the aspect ratio in the description, like 175/80/14. 

Does your tire have any markings on either side that appear to have been molded with removable mold pattern tags like the KLILX mark on mine?

Edited December 17, 2023 by CanTechZ

[davewormald]

My car (the one @grannyknot is working on at the moment), has the original spare, we believe. The car is 04/71, HLS30-29817. If the spare wheel isn't buried, maybe Chris can get the info off it for you. I'm not looking to sell it, but maybe it can provide another data point for you.

[CanTechZ]

21 minutes ago, davewormald said:

My car (the one @grannyknot is working on at the moment), has the original spare, we believe. The car is 04/71, HLS30-29817. If the spare wheel isn't buried, maybe Chris can get the info off it for you. I'm not looking to sell it, but maybe it can provide another data point for you.

Would be interesting to see if yours has the 10 digit DOT number like the BaT 8/71 example above. 

[grannyknot]

I'll dig it out tomorrow morning and see if I can get a closer shot.

[davewormald]

6 hours ago, CanTechZ said:

Would be interesting to see if yours has the 10 digit DOT number like the BaT 8/71 example above. 

From the picture just posted it doesn't look like it. You can see DOT at about 8 o'clock, but there's nothing following it. Unless it's on the other side.

[CanTechZ]

9 minutes ago, davewormald said:

From the picture just posted it doesn't look like it. You can see DOT at about 8 o'clock, but there's nothing following it. Unless it's on the other side.

It would be worth checking, on mine there is what I think might be a date code on the inside. My spare is from a 7/70 and is definitely is not in the standardized DOT format with 10 digits that started in 1971. 

[inline6]

Here are some more pictures of my spare.  VIN HLS16530 - 12/70:

High resolution front and back:

 

 

I claim that I have the earliest Toyo Z tire for 240z's still in existence - someone prove me wrong!