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Thread: Upgrade From 35's?

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    Upgrade From 35's?

    My 2500 has been running 35s ever since I bought it.

    I wonder if there is any larger size that I can go to, however small or big of an increment, that would not require me to do any axle regearing (which I'm not positive of my ratio now).

    Any ideas?

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    trick76cj5's Avatar

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    Re: Upgrade From 35's?

    37’s will fit with the correct backspacing and a little trimming of the inner fender and pinch weld.

    They work better with a leveling kit in the front, though.

    Gearing is a personal choice.

    The 68RFE is not the strongest in the world, so adding extra load isn’t great for longevity.

    Increasing tire size reduces your effective final gear ratio, which adds load to the trans.

    This typically isn’t significant if you don’t tow heavier.

    When I was researching, many transmission builders will not warranty a built 68RFE w/larger than 35” tires unless it has been reheated accordingly.

    So I used that as a good rule of thumb in my decision process.

    There are tricks to make the lower gearing work while towing, like manually shifting and not letting the truck into 5 or 6 gears (the OD gears … it’s the OD clutches most affected by the tire size).

    My truck came with 3.42 gears 35’s wired ok on that gearing.

    I swapped in 4.10 with 35’s, and the truck woke up around town but felt like it revved too high at 80mph on the highway (wit as excellent at 70, but I live in Florida and will get run over if I run 70).

    I then installed my 37’s and the gearing felt perfect.

    If you have anything larger than a 3.42 and are tuned, you will probably not mind the 37s.

    If you are running 3.42’s, I can tell you from personal experience that 35 is a great tire with that gear.

    Good luck with your decision!

    Here is a pic of my truck on a 3.5” lift and 37’s:




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    trick76cj5's Avatar

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    Re: Upgrade From 35's?

    Sorry, phone auto corrected me:

    Reheated = re-geared

    Thanks


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