larger tires and fuel economy. why?

[millermayhem]

wouldn't putting larger tires reduce the engine rpms resulting in better economy? I am kindof lost...

 

[Hahnsb2]

No, more mass and width as well as putting your RPMs in the incorrect range, low RPMs doesn't = fuel economy, you want to cruise around peak torque, too low and you lug the engine using more fuel than letting it rev. Don't think drving 55 at idle speed will give you the best fuel economy.

 

[millermayhem]

I see... thank you.

 

[85_Ranger4x4]

And even if you regear, you are asking your engine to spin 4 heavier flywheels, and that takes more power as well.

 

[chazzone]

Maybe not

I think that there is some wiggle room here, guys. I went from the stock 205's (getting about 18 on the highway) to 235's (29.5") and got better mileage with 3.73 gears.

I ran Pirelli's for years, and now I have Michellin's, and I get 20-21 mpg corrected.

Now I'm sure you could put a lot heavier tire of the same size, or one that doesn't roll as well, and drop mileage.

I'm also sure that if I went to any taller tire with those gears, I'd have a drop in mileage, too.

-zz

 

[pillen140]

i get better gas mileage with my 33's then i did with 235's. but at the same time they are only 33x10.5's. and the tire and wheel combo im using was a lot lighter then the stock heavy as shit steel wheels that were on there. thats with 3.73 by the way. went from 15-16mpg in the city to average about 18-19 in the city. close to 23 on the highway.