Disapointed with MPG.
Postmaster
Joined: Aug 2003
Posts: 4,483
Likes: 2
From: Central Texas
I drive like an old man ( I am). I got messing around with tires and rims and that had a huge impact on mileage. With the stock tires on 20" rims I was getting 17.5 mpg according to the the trip/fuel display. I took a big hit on mileage when I put the 18" rims with P265/60 tires on it. I now have LT275/65 R18's on the truck that should return me to the original mpg performance. I would get between 20 and 21 mpg on straight highway driving at 60-65 mph. I should get that again with the ne, w tires. I am at sea level to 750' ASL.
I have have had the TCM module adjusted to accommodate tire changes. I have use an accurate hand held GPS unit to check mph, distance and it closely matches the Ford MyTouch display.
If you put oversize or undersize tires and lift kits, it will have a big hit on mpg.
I have have had the TCM module adjusted to accommodate tire changes. I have use an accurate hand held GPS unit to check mph, distance and it closely matches the Ford MyTouch display.
If you put oversize or undersize tires and lift kits, it will have a big hit on mpg.
Last edited by SBV45; Feb 16, 2015 at 01:16 PM. Reason: Update
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Mountain Pass
Joined: Dec 2004
Posts: 216
Likes: 8
From: mich.
Well did the 240 mile trip again yesterday.Pretty much no wind about 70 degrees. This time I ran 65 mph and got just under 23 mpg per the dash gauge.Guess if your not in a hurry you can get really good mileage!
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Mountain Pass
Joined: Dec 2004
Posts: 216
Likes: 8
From: mich.
I,m in south florida.Where I,m from in Michigan it was -14 this morning.I,m staying here for a while!
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Postmaster
Joined: Aug 2003
Posts: 4,483
Likes: 2
From: Central Texas
Now that I have the new tires on the truck, I have been showing 13.5 mpg.
That is a +/- 22.5% decrease in mileage compared to the mpg with the original Pirelli Scorpion ATX P275/55 R20 tires. I replaced all four wheels with Goodyear Wrangler AT/S LT275/65 R18 which is what Ford provided as a spare.
Comparing the Wranglers to the Pirellis shows the Wranglers to be slightly larger in circumference (0.52 in) and larger in diameter by 0.16 in and requires fewer revs per mile by 3.26.
The speedometer was recalibrated to the LT275/65 R18 tires. A check with a separate GPS appears the speedometer is fairly accurate.
Logic would dictate that I should be getting pretty close to the original 17.5 mpg overall, but I don't.
The service manager says it is the new tires that is causing the drop in mileage.
That is a +/- 22.5% decrease in mileage compared to the mpg with the original Pirelli Scorpion ATX P275/55 R20 tires. I replaced all four wheels with Goodyear Wrangler AT/S LT275/65 R18 which is what Ford provided as a spare.
Comparing the Wranglers to the Pirellis shows the Wranglers to be slightly larger in circumference (0.52 in) and larger in diameter by 0.16 in and requires fewer revs per mile by 3.26.
The speedometer was recalibrated to the LT275/65 R18 tires. A check with a separate GPS appears the speedometer is fairly accurate.
Logic would dictate that I should be getting pretty close to the original 17.5 mpg overall, but I don't.
The service manager says it is the new tires that is causing the drop in mileage.
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Mountain Pass
Joined: Dec 2004
Posts: 216
Likes: 8
From: mich.
My truck has the Goodyear Wranglers. Maybe that's the problem? My last truck(2010 F150) had Goodyears and they only lasted 50k miles.Maybe when I wear these out I,ll try something else.
Lead Driver
Joined: Jun 2005
Posts: 8,465
Likes: 725
From: Calgary Canada
Now that I have the new tires on the truck, I have been showing 13.5 mpg.
That is a +/- 22.5% decrease in mileage compared to the mpg with the original Pirelli Scorpion ATX P275/55 R20 tires. I replaced all four wheels with Goodyear Wrangler AT/S LT275/65 R18 which is what Ford provided as a spare.
Comparing the Wranglers to the Pirellis shows the Wranglers to be slightly larger in circumference (0.52 in) and larger in diameter by 0.16 in and requires fewer revs per mile by 3.26.
The speedometer was recalibrated to the LT275/65 R18 tires. A check with a separate GPS appears the speedometer is fairly accurate.
Logic would dictate that I should be getting pretty close to the original 17.5 mpg overall, but I don't.
The service manager says it is the new tires that is causing the drop in mileage.
That is a +/- 22.5% decrease in mileage compared to the mpg with the original Pirelli Scorpion ATX P275/55 R20 tires. I replaced all four wheels with Goodyear Wrangler AT/S LT275/65 R18 which is what Ford provided as a spare.
Comparing the Wranglers to the Pirellis shows the Wranglers to be slightly larger in circumference (0.52 in) and larger in diameter by 0.16 in and requires fewer revs per mile by 3.26.
The speedometer was recalibrated to the LT275/65 R18 tires. A check with a separate GPS appears the speedometer is fairly accurate.
Logic would dictate that I should be getting pretty close to the original 17.5 mpg overall, but I don't.
The service manager says it is the new tires that is causing the drop in mileage.
- The new tires will have a higher rolling resistance than the old ones. Yes, that's a real factor.
- Those new tires a lot heavier than your old ones. This should be a bigger factor around town.
P-metric tires may not make sense for a lot of us, but they do get better mileage then LT tires, I think that's been proven time and again on these forums.
Postmaster
Joined: Aug 2003
Posts: 4,483
Likes: 2
From: Central Texas
77,
Thanks for pointing out a couple things I overlooked.
1. My current Wranglers weigh 6.1 pounds more per wheel than the original Pirellis.
2. The Wranglers do have a more aggressive tread suitable for off road and mud.
I expected somewhat of a hit on mileage but not 22%.
I guess the above coupled with winter blend gasoline will add up.
I will be taking a road trip to South Texas this week, most of it highway driving but with off road sandy clay two tracks that get slick when wet. I'll see what happens and I'll let you all know.
A friend of mine that I meet down there had a new F150 and complained that the stock Pirelli Scorpions were fine on the road but poor on the two tracks around the ranch.
Caveat emptor!
Thanks for pointing out a couple things I overlooked.
1. My current Wranglers weigh 6.1 pounds more per wheel than the original Pirellis.
2. The Wranglers do have a more aggressive tread suitable for off road and mud.
I expected somewhat of a hit on mileage but not 22%.
I guess the above coupled with winter blend gasoline will add up.
I will be taking a road trip to South Texas this week, most of it highway driving but with off road sandy clay two tracks that get slick when wet. I'll see what happens and I'll let you all know.
A friend of mine that I meet down there had a new F150 and complained that the stock Pirelli Scorpions were fine on the road but poor on the two tracks around the ranch.
Caveat emptor!