I want to put taller tires on my 2007 dually. I have stock 235X80X17 and am thinking of putting on 245X75X17 to help in the mileage department.
Anyone know if I'll need spacers ? Or has anyone tried and what are the results ?

 

245/75s won't be taller, they're about 1.2" shorter. That will increase the revs/mile. Taller would be a 245/80 (tiny difference - it would take a long time to recoup the cost).

Edit: not that much shorter, but still shorter by a teeny amount.

 

for a fact i know the biggest tire you can run on your dully without using spacers is a 285 70 17....i used to work for discount tire co. and i would see dullys like that come in all the time

 

That would be taller, but only by 3%. If they cost much more, the fuel savings would take a long time to break even.

 

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