New tires & fuel economy

[wyodan]

Hey there, new to the forum & just picked up my first diesel. So I got a question. I just went from 265 70 18 highway tires to 275 70 18 all terrains. It seems I lost about 2.5 to 3 mpg. Does that seem reasonable?

 

[whitetrash21]

Hey there, new to the forum & just picked up my first diesel. So I got a question. I just went from 265 70 18 highway tires to 275 70 18 all terrains. It seems I lost about 2.5 to 3 mpg. Does that seem reasonable?

No. I went from 265/75-16 on pyo's to a 20" Fuel wheel with 33" Toyo M/T tires.....far heavier than the stock combo was. I only lost ~1 mpg. 3 mpg is a little extreme unless you're going up to 35s or 37s from stock. I lost about that much or a little more when I went from 32s to 38s on my 05.

For the small change in tire size, you're losing mileage somewhere else

 

[wyodan]

No. I went from 265/75-16 on pyo's to a 20" Fuel wheel with 33" Toyo M/T tires.....far heavier than the stock combo was. I only lost ~1 mpg. 3 mpg is a little extreme unless you're going up to 35s or 37s from stock. I lost about that much or a little more when I went from 32s to 38s on my 05.



For the small change in tire size, you're losing mileage somewhere else

Thanks for the reply. They leveled my truck with the stock torsion keys, maybe a little more than I wanted. And they aligned it to. Do you think there's any chance something is off there? My truck looks sweet right now though.

 

[Awenta]

No.

Hand Calc or gauge?

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[wyodan]

I just used the gauge, but I didn't think it would significantly change. The tire size was only going to make a 1 mph difference at 65.

 

[Awenta]

Hand Calc a few times and then see. It isn't that much for sure

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[Lparrill]

Don't trust the dash. It lies horribly. Hand calculated is the only way to really tell.

 

[whitetrash21]

Thanks for the reply. They leveled my truck with the stock torsion keys, maybe a little more than I wanted. And they aligned it to. Do you think there's any chance something is off there? My truck looks sweet right now though.

Level and alignment won't affect mileage....unless they fiddle fucked your alignment way off, at which point you'd notice it handling far worse. All you changed was tires??? Still on the same wheels??

Don't trust the dash. It lies horribly. Hand calculated is the only way to really tell.

X2

 

[wyodan]

Level and alignment won't affect mileage....unless they fiddle fucked your alignment way off, at which point you'd notice it handling far worse. All you changed was tires??? Still on the same wheels??







X2

Yep, all I changed was the tires. Drifts right a bit after the align, although he said he had it adjusted to track straight.

Thanks for the input, I'm gonna do some more checking & maybe take it back tomorrow.

 

[Stancedlb7]

Check your tire pressure.

 

[wyodan]

Tire pressure is good. Would switching from Michelin highway tires to Cooper ST MAXX make that much of a difference?

I'm going to take it back in today to make sure the alignment is fine. It feels like it pulls right to me now. He said he had it set to track straight.

 

[whitetrash21]

Tire pressure is good. Would switching from Michelin highway tires to Cooper ST MAXX make that much of a difference?

I'm going to take it back in today to make sure the alignment is fine. It feels like it pulls right to me now. He said he had it set to track straight.

A wider tire has to be aligned somewhat differently than a stock tire. Alignment shop put an extra 1.5* of castor on my passenger side. Supposed to help the pull that wide tires give when driving on roads with a crown. Mine tracks straight on most roads..... Only the occasional wander.

Regardless, that issue will not affect your mileage in the way your mentioning.

 

[JDub]

Just the style of tire made a big difference in my lb7 mileage. I had 285/65r18 nitto a/t and averaged 18mpg, swapped to 285/65r18 nitto trail m/t amd dropped to 16mpg. Couldnt take the mileage loss and noise and swapped back, mileage is right back up to 18

 

[1ATony]

welcome to the site
Tony :hello:

 

[longball]

New tires & fuel economy

Did you recalibrate the speedometer after the tire change? That can make a difference. When you're keeping up with hand calculated mileage it's nice to have the fuelly app.


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[Rancelot211]

I went from 265s to 33s and lost about 4 mpg.