Mixing Tire Sizes

[Arne]

I understand the formula. I also know the 16" tires are 1" shorter than the tires I took off the Z. (I have pics of this. Pics don't lie!) The source quoted to me states the 14" tire is shorter. I am wondering why?

I recognize the tire from its tread pattern. The old one was a Sears/Michelin, and I guarantee to you that they were NOT 175/65-14, as there was no such thing as a 65 series tire back when those were made. That tread design was current when I first got into the tire business in '75. It was the Sears version of the Michelin ZX, and for the most part the Sears version was only available in 80 series sizes. (The Michelin ZX and later XZX were both available in 70 series, but no 65 series at all.) The size on that tire would have been "175SR14" and would be dimensionally the same as a 175/80-14.

[ZSaint]

Arne you have way too much knowledge about tires! You are correct! This was my spare. It is indeed a 175SR-14 tire! I had a set of Goodstones on the car. I just grabbed a wheel when I took the pic. How old is this tire? I bet it is 20 years+. What do you think?

[Arne]

That's what you get when you spend 20+ years in one industry - too much knowledge. And I'll likely have too much about tires forever, even though I've been in IT for 8 years now.

Age? That Sears tire is closer to 30 years old, I'd say. Look at the last three digits of the DOT number, found one sidewall only. It will be in the format of 'DOT XXXX XXXX 888' where X's are either letters or numbers, but 8's are always numbers. Those final three numbers give the production date. The first two are the week, and the final being the year. Therefore 267 would be the 26th week of a year ending in 7. (Lately they've finally gone to four digits, which means there is no longer any doubt as to the year.) In the case of your Sears tire, I'm almost certain it was built in the '70s.