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Tires/G78 tires


what is the current conversion from the old G78 tires to the new ex. 205 75 15


There isn't one.

The G78's are 78 aspect ratio and they just don't make those anymore.

However, there are close approximations, if you don't need to be exact:

Short version:  

P215/75R14 or P205/75R15

And you will have problems finding those sizes.  If you go into 70 series tires, it starts to get a little funky in that the wheel widths are much wider and I feel uncomfortable recommending 70 series without changing the wheels.  

But if you need an exact fit, then look up Coker Tire.  They sell tires in that size.  


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Barry Smith


I have over 30 years experience in the design, manufacturing, and testing of tires. I have served as the technical advisor to the "800" number. I have authored or co-authored many publications - usually without credit. I can answer almost any technical question, but please don`t ask me to compare brands. I probably have prejudices because of my work experience.


Member SAE (Society of Automotive Engineers) Member Tire Society (Tire Technical Organization) SCCA Regional Competiton License holder Authored many training manuals on tires, their care and use.

SAE (Society of Automotive Engineers) SCCA (Sports Car Club of America) Tire Society

You may want to visit my web site:

I am a graduate of the University of Dayton, Dayton, OH - BME, 1971 I attended graduate school at the University of Akron - but did not complete my PhD - something I regret.

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