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Tires/Oversized Tires


I have a 2009 Chevy 2500 Express van with a duramax diesel that calls for LT 245/75 16 tires.  I would like to go to a LT 265/75 16.  I understand this will alter speedometer readings slightly but are you aware of any other potetial problems going to this size on this vehicle?  Also, how will this affect fuel economy?


According to Tire Guides, the wheels on your truck are 6.5" wide - and an LT265/75R16 requires a minimum of a 7" rim. Using a rim that is too narrow may make the vehicle track the grooves and ruts in the road, plus make it sensitive to cross winds.

Fuel economy?  Tire size doesn't play much of a role in fuel economy - other than make the engine turn slower.  That sort of thing has been proven to help, but the reduced torque sometimes causes people to press harder on the accelerator and negate the improvement.


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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

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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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