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Tires/tires for larger rims


Hello my name is AnTonio I have a 2005 Cadillac STS it currently has 17"x7.5 rims front tire size 235/50/17 rear tire size 255/45/17 I was wanting to put 20"x8 rims what would be the best tire sizes for this set up and do I need to keep the tire size split or can I put the same all round as far as the height goes? THANK YOU


Both Tire Rack and Discount Tire have on line tire upsize programs.

Follow those for the best advice available.  They will tell you about the staggered fitement, but I think the car is supposed to have the stagger continued for handling reasons - but both of them will tell you the answer.


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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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