Is there a Bigger Wheel/Tire combo that will give me the Same MPG as the Stock 18

[Pwarrenn]

would like different wheels on my 2008 but do not want to give up MPG..Am I stuck with the Stock set up?? I have 18's with the 275 conti's I think..

??????

[NJF350SD]

Circumference is going to be your main key. You can change your wheel/tire combination, so long as you don't change the overall circumference of the tire, your effective gear ratio will not change and thus you could retain the same fuel mileage.

Now I said "could". For example: If you go to a 20" rim and a lower profile tire to fit with the circumference idea, you would be likely adding significant rolling mass to your wheel/tire combination which could [would likely] result in lower fuel economy from the added power needed to rotate the additional mass.

[texastech_diesel]

Check the Revs per mile on the tire. Different tire with the same revs will run mostly the same.

You can go by circumference if you want I guess. For example: Go to the Nitto website and open the specs on one of their Grappler tires. It will list an actual circumference, so that's a very rough way to guesstimate similar size between different width/aspect ratio/wheel sizes.

[wwb]

Tall, skinny, & hard (high pressure) = good mpg
Short, wide & soft = poor mpg
Tall, but wide = in between

Your choice.

[diesel_dan]

Originally Posted by NJF350SD

Circumference is going to be your main key. You can change your wheel/tire combination, so long as you don't change the overall circumference of the tire, your effective gear ratio will not change and thus you could retain the same fuel mileage.

Now I said "could". For example: If you go to a 20" rim and a lower profile tire to fit with the circumference idea, you would be likely adding significant rolling mass to your wheel/tire combination which could [would likely] result in lower fuel economy from the added power needed to rotate the additional mass.

That's been the opposite of my experience (mostly high performance cars). The rubber and structural components of the higher ratio tire (taller sidewall and perhaps wider tread) outweigh the larger diameter alloy wheels (with a lower aspect ratio tire) -- especially our forged Ford rims. Going to a 20" wheel (ala: Ford's 20" tire/wheel combo), would increase your circumference and diameter slightly, but should weigh less overall, and with reduced rotating mass, likely increase your mileage, albeit only slightly. Your right foot has far more to do with mileage than just about any other change you could make...

I haven't actually weighed the two, so this is an extrapolation based on past experience. I'd be interested if you could find someone with the 20's set up and pop a wheel/tire off and weigh yours back-to-back. It's important to use the same scale, same temp, etc. to have a direct comparison.

If you do this, let us know what you find -- those 20" take-offs I see advertised may jump in price with these fuel prices...

[duffman77]

If you spend any kind of time on this site, one thing you will learn is that 2 things tend to be present on trucks with poor MPG: Lifts and big tires. Dont alter your tires if you want MPG.