LOST 3MPG!! WTH?
Hotshot
Joined: Nov 2008
Posts: 15,014
Likes: 35
From: Semper Fi tell I die!
Cargo Master
Joined: Oct 2006
Posts: 2,097
Likes: 5
From: chicago northwest suburbs
Before I switched from the 3.73`s I was geting 15mpg hwy with the stock Pirrelli Scorpions with the hwy tread. then with the switch to 4.30`s I would only get 14 hwy. which is where I`m at now. I did have some issues with poor gas mleage ( i was down to 12.5 hwy) with the crappy ethanol blended fuel, but with running 93 my mpg is back to 14 hwy!
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Senior User
Joined: May 2010
Posts: 364
Likes: 0
From: mt.prospect
Update, Discount tire put new rugged trails back on for me problem solved.
All terrains felt like the truck was pulling a parachute.Even at 70 psi.
Truck rolls real nice. I'll post back with my gas mileage difference.I'm very happy. Thanks Discount tire
All terrains felt like the truck was pulling a parachute.Even at 70 psi.
Truck rolls real nice. I'll post back with my gas mileage difference.I'm very happy. Thanks Discount tire
Posting Guru
Joined: Oct 2003
Posts: 1,198
Likes: 2
From: Tulsa, OK
Well I'll make the mistake of talking about something I know little about, so everyone keep that in mind as you read this and cut me some slack.
From looking at the two different tires, it appears that you went from an all terrain tread pattern to more of an off road / snow tire pattern. The leading edges of the tread blocks on tires with an aggressive tread pattern are going to really dig in until they wear in a bit. That might explain some of your mileage loss.
Next, you should compare the weight of your old tires when new to your new tires. The reason is that a heavier tire is going to mean a larger reciprocating mass that will require more energy get moving and keep moving. In short, heavier tires = less mileage. On top of that, since your old tires were worn, they were even lighter than they were when new. Once again, heavier tires = less mileage.
Were both your new and old tires the same load range? Going from say a "D" load range tire to an "E" load range is going to give you a heavier tire - you get the idea.
Finally, even if both of your tires were the same size, you should check the revolutions per mile specification for each tire. There can be a bit of variation in actual tire size, even though the size stamped on the sidewall reads the same. A smaller tire will overstate your miles per gallon, a larger one will do the opposite.
You should be able to check all this information at BFG's web site. Hope this helps.
From looking at the two different tires, it appears that you went from an all terrain tread pattern to more of an off road / snow tire pattern. The leading edges of the tread blocks on tires with an aggressive tread pattern are going to really dig in until they wear in a bit. That might explain some of your mileage loss.
Next, you should compare the weight of your old tires when new to your new tires. The reason is that a heavier tire is going to mean a larger reciprocating mass that will require more energy get moving and keep moving. In short, heavier tires = less mileage. On top of that, since your old tires were worn, they were even lighter than they were when new. Once again, heavier tires = less mileage.
Were both your new and old tires the same load range? Going from say a "D" load range tire to an "E" load range is going to give you a heavier tire - you get the idea.
Finally, even if both of your tires were the same size, you should check the revolutions per mile specification for each tire. There can be a bit of variation in actual tire size, even though the size stamped on the sidewall reads the same. A smaller tire will overstate your miles per gallon, a larger one will do the opposite.
You should be able to check all this information at BFG's web site. Hope this helps.
You would have to have a huge increase in mass of tires to make measurable difference in MPGs. Now, if you had a change in diameter, that can really affect the economy. But, change in rotational mass of maybe 10 - 15% would not allow huge change in gas mileage. I think this is a common misconception because many of heavier tires are a bigger diameter. Changes in effective gear ratios can make a big difference in fuel economy.
In this case, the road friction and the negative affect on aerodynamics (spinning agressive tread) probably accounts for decrease in MPGs.
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Senior User
Joined: May 2010
Posts: 364
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From: mt.prospect
I hate to say but I don't notice any increase in gas mileage with the rugged trails. YET bfg's web site shows the rugged trail as a 8 for gas mileage and the A/T as a 6. If the all terrains would of balanced out so I wouldn't be shaken all the way to work I would of kept them. Def. a Kick -**** tire made my truck look off road tough.
Winter blend fuel is the winner. Killed 2 to 3mpg.
Winter blend fuel is the winner. Killed 2 to 3mpg.
Postmaster
Joined: Oct 2006
Posts: 4,171
Likes: 12
From: SE Texas
Yet you can claim that they're crap a few posts back.
I have the RT's on both my truck and the Excursion. They're a good tire that last an exceptionally long time. Traction is good in the wet, dry, and snow.
They work.
They're not crap.
JL
I have the RT's on both my truck and the Excursion. They're a good tire that last an exceptionally long time. Traction is good in the wet, dry, and snow.
They work.
They're not crap.
JL
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Senior User
Joined: May 2010
Posts: 364
Likes: 0
From: mt.prospect
13 hours. I use the lie-o-meter as a reference.
I can tell you one thing. Driving to work 100 miles round trip for 3 months in the summer ,the obc showed 16 to 17 mpg in the summer. Now I'm lucky if it shows 15. Using the cruise locked at 70mph.
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Senior User
Joined: May 2010
Posts: 364
Likes: 0
From: mt.prospect
Wow! Thats thirsty. Yea in 340 miles all highyway driving my trucked used 27gallons on a real windy cold day.12.7 mpg. It's better now.
I did a bunch of reading on the differences between summer and winter fuel. One major difference is the amount of isobutanol is much less in the winter blend and the fuel molecules are charged with butane. Wonder if I can buy a gallon of isobutanol from a paint supplier?
Bleed Ford Blue
Joined: Apr 2009
Posts: 13,578
Likes: 157
From: Anchorage Alaska
yep shes around 7-8mpg right now lol but its winter, in 4x4 all city and idle/warm up time. i can hit the double digits in the summer
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