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MG TD TF 1500 - Tire Aspect Markings

I'm writing a Tech Tip about tires for our club's January newsletter. The discussion includes aspect ratios. I'm stumped because I can't find the aspect ratio of some of the tires that are often recommended for our cars.

> If a radial tire does not have an aspect ratio indicated, then what is the aspect ratio? 80? Is it always the same when no ratio is indicated?

For example:
Vredestein Sprint Classic 165/HR15 tires do not indicate the aspect in the on-line documentation. What is the aspect ratio? How do I know? Do these tires have an aspect ratio stamped on the sidewall?

Vredestein Sprint Classic are also available in a 185/70HR15 tire, which obviously has a 70 aspect ratio, so it's indicated for some tires.

The Classic brand tires on my TF are stamped "165/80-15" so they are definitely have an 80 aspect.

Thanks for your help,

Lonnie
TF7211
LM Cook

Still looking for aspect ratio info on Vredestein Sprint Classic 155R15 and 165R15 tires.

I found this on the Automotive Mileposts site:
http://automotivemileposts.com/tires101.html

"... some Euro-Metric tires have Aspect Ratios listed in the sizing, while others don't. This is due to the fact that the Euro-Metric system was originally set up with an Aspect Ratio of "82" and it wasn't included in the sizing at that time since all tires had this as the default."Automotive Mileposts website

And FYI - I found this interesting tidbit on the Coker Tire blog regarding aspect ratios of bias ply tires:
https://www.cokertire.com/blog/aspect-ratio/

"Aspect ratio for most bias ply tires is somewhere around 80 or 90 percent. Numeric sized tires (such as 6.00-16 or 6.70-15) that end in zero feature a 90-series aspect ratio, while numeric sizes that end in five (such as 6.95-14) feature an 80-series aspect ratio."

I know that this subject has been beat to death.

Lonnie
TF7211
LM Cook

Lonnie,
You could measure the tires to find the ratio.

Steve
Steve Wincze

Steve -

Maybe so. But they will stretch a little so the computed ratio may not be the stated ratio (assuming that the ratio exists somewhere.)

I'm only doing the exercise to be able to learn about tires for T-cars plus As and Bs for my Tech Tip article.

Thanks,

Lonnie
TF7211
LM Cook

The aspect ratios are a relatively new way of specifying tires. The older ones, like the Vredestein you cite, don't do that. You can find a table of equivalences on-line; I'm not at my office now, so I can't give you a link, but you can google it. If you look at some of the classic tire sellers, I think they have such tables. You might start with Coker Tire or Lucas Classic Tires.
S Maas

I found the answer to my question.

Metric width tires that do not specify the aspect ratio have a 80 or 82 aspect ratio. Vredestein Sprint Classic 165R15 tires are 25.4" in diameter. The Classic brand 16580R15 tires on my TF are also listed as 25.4" diameter. So the Vredestein are have an 80 aspect ratio even though it is not stated.

Lonnie
TF7211
LM Cook

This thread was discussed between 23/12/2015 and 26/12/2015

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