The nmber in the center of the tire size

[Walter Reich]

I have a 356 C coupe. The tire size on the car is 165/SB/15 SB Steel Belted is what I am looking for but All that I can fined is 165/70/15 or 165/80/15 What is the difference. Is there a standard profile size for the SB on the tire,70 or 80. The tires on my car are old and I will need changing. I would like the help from you guu ruu ss. I am learning slowly. I hope to have the car completed by the end of DECEMBER.

Water Reich

[Greg Bryan]

It's the aspect ratio in percent - ratio of height to width of the tire
70 is a lower profile than 80 etc

[Alan Hall]

As I recall the aspect ratio of an original 165-15 tire that is not otherwise marked is 82. Thus a 165/80-15 would be the closest to what you currently have.
Alan

[Walter Reich]

Thanks I didn't know the profile that the SB stood for. Now I will try to get 165/80/15 Good help here in the Registry is everything.

THANKS AGAIN

[Doug McDonnell]

Walter the S is speed rating (112 MPH) and the B means the tire is Bias Ply. So you have bias ply tires rated for 112 MPH. There is a permanent stickie at the top of the main discussion forum that discusses tires,sizes,fitment issues etc. Tire choice can also be limited by whether you are using original 4.5 x 15 stock rims or if you are upgrading to wider rims. Default aspect ratio for 15" rims is 78. So your old tires are 165/78/15. Here is a conversion table for tire sizing http://www.tirerack.com/tires/tiretech/ ... chart.html

[Greg Bryan]

You should read the tire sticky thread - I can't believe you'd want an aspect ratio over 70
I don't belive they were using the current tire nonanclature in 64 and 65 era - and I don't think any C was shipped with bias ply tires - I could be wrong, but definitly put radial tires on your car
I think a typical tire similar to the era is a 165/65/15 -
356s that have tires that are too tall (higher aspect ratio) don't look right

[Doug McDonnell]

Greg I agree he should put radial tires on and that C's probably came with radial tires. The question was what the sidewall meant. The tires he has are not original. And lots of people put "cheaper" bias ply tires on their cars in the 60s and 70s. As to what "looks right" all of us who use correct aspect ratio for 1965 on original 4.5" rims have funny looking skinny tires! 165/78/15 in modern nomenclature.

[Jim Alton]

I pulled the overall diameters and section widths from a couple 165R15 tires at Coker Tire's website:

Michelin XZX - 165SR15
Section Width: 6.40
Overall Diameter: 25.40 Aspect Ratio = 0.81

Vredestein Sprint Classic - 165HR15
Section Width: 6.60
Overall Diameter: 25.40 Aspect Ratio = 0.79

Vredestein T-Trac - 165/80R15
Section Width: 6.55
Overall Diameter: 25.38 Aspect Ratio = 0.79

Michelin XAS - 165HR15
Section Width: 6.30
Overall Diameter: 25.60 Aspect Ratio = 0.84