Interesting Marking on Original Speedway Tire

I was organizing the attic the other day and noticed something on the sidewall of one of my small letter Speedway tires. Just ahead of the "350," you can make out the ghost of the letters "GT" pressing through the top layer of black rubber. The font is the same as the rest of the lettering and is visible on the inside and outside sidewalls. I didn't have a chance to compare the date code with any of the other six original tires I have, but figured I'd post a couple of pictures to see if anyone else has ever noticed this. Kind of tough to take a picture of, this was the best I could do.

 

Kind of what I was thinking, Bob. I'd bet this is an early date code tire. I'm guessing they scrubbed the "GT" from the mold for the lower white rubber layer. Since it was getting covered, they didn’t do a thorough job of removing the lettering and after all these years, the ghost is starting to show through. I love finding this kind of stuff

 

Yes, Jeff, this is a small-letter Speedway (see first post). There was no sign of the ghost on any of the other six small letter Speedways I have. I experimented with the close-up and flash settings on my camera and shot the ghost from different angles on both the front and backside of the tire. This was about as good as I could do. We are out of town til the middle of next week, but I will check the date on the tire when we get home and post back.

 

I never knew that, Jim. The tire has the identical ghost on both sidewalls. I'm thinking there wouldn't be much sense in adding the letters to the backside of the tire. The 350 is not raised white letter, so it would look kind of funny to just say Speedway GT, but I guess anything is possible. I'll scrub the sidewall and see what happens.

I don't know how to decode it, but the date on the screwed on mold tag on the inside sidewall between Speedway and 350 is MROMK97. I'm guessing 9th week of 67. Any takers?

 

I found the old Goodyear date code system on the SAAC forum at:
http://saacforum.com/index.php?topic=1939.0

First digit
66=M/Z
67=K/Y
68=L/T
69=J/U
70=E/W
71=H/X
72=G/S

Second digit
Months are (from 1, Jan, to 12, Dec) T,U,F,S,Y,N,P,A,C,K,E,R

That would put MROMK97 with a build date of December 1966.

 

Thanks, our messages crossed and I found your post on the SAAC forum with a Google search!

 

From TLEA's post on the SAAC forum, I don't think the 97 has anything to do with date of manufacture. OM is the plant code, but I don't know how to decipher it.

Dave Redman stopped by today to check out the progress on my Model A hotrod and happened to have his camera with him. He took a couple whiz bang close-ups of the GT ghost. I updated the pictures in my original post and have attached them below for reference. You can actually feel the bump in the sidewall of the characters in the underlying casing.

We rooted through the tires I had in the attic and the one in the trunk of #1547. Turns out I actually had another tire with the GT ghost. Dave also picked up on a detail I had failed to notice. The lettering on the blackwall side of the tire had been highlighted with white paint the way Goodyear used to do on the Blue Streaks and their racing tires.

While we were at it, we compiled the date code information on all the small letter Speedways I had:

Nov 1966: Possible GT ghost (This was the tire in the trunk of #1547 and I didn't feel like dragging it outside to get a better look in the daylight)

Dec 1966: GT ghost on inside and outside sidewalls (MROMK97; pictures posted)

Jan 1967: GT ghost on inside and outside sidewalls (KTOZP46)

Apr 1967: No ghost (two tires with this date code)

Feb 1968: No ghost

It's starting to looking like the early small letter Speedways had the GT ghost. I don't know how to decypher the plant code, but it is different on the two tires with GT ghosts, so this does not look like an anomaly limited to a singler plant. I have included the full tire codes for both tires for future reference. Next time I'm feeling ambitious, I'll pull the spare in #1547 to see if it lines up with the early date code pattern.