Does this sound right?
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Freshman User
Joined: Sep 2002
Posts: 29
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Does this sound right?
I've got a 1994 F150 4x4, 300ci motor, E4OD tranny, 3.55 gears, standard cab, long bed, 146,000 miles. I'm currently running 32"x11.50" Mastercraft Courser MT tires and I'm seeing a consistent 12.5mpg that is mainly highway driving. I've eased up on my driving habits quite a bit trying to get better gas mileage but I'm still seeing the same 12.5mpg, every once in awhile I'll see a 12.7mpg. I've changed all the typical tuneup parts and the motor runs great. I'm wanting to know if this mileage sounds about right, I think it sounds pretty low, I understand it being low because of the bigger tires but I wouldn't think it would be that low. I plan on getting my exhaust worked on sometime soon, I'd like to get rid of my cats and replace my muffler with a better flowing one. If you guys have any ideas on something that may be bad on my motor as far as a senor or something like that that may be resulting in this bad gas mileage please let me know. Thanks in advance.
Elder User
Joined: Dec 2001
Posts: 582
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From: Kelowna B.C.
Does this sound right?
I'd love 12.5 mpg. I've got a 88 F150 shortbox extracab 4X4 5.0 AOD 3.5 gears ,mild cam ,K&N filter ,free flowing exaust, shorty headers, 31 X 10.5 mud terains, 8000lb warn. I get around 10mpg. But its my huntin fishin campin weekend truck so mpg isn't that important. I drive a 98 1 ton chev van for work and I drove like a granny for one tank and drove around normal(for me-a little lead footed) on another14.5 mpg mainly in town either way!?
Freshman User
Joined: Apr 2003
Posts: 44
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From: near harrisburg
Does this sound right?
I have a 92 f150 with the same tires but with a manual trany. I did notice better milage with a cap or lid on the bed. I average 13.3 city and 14.5 highway. depending on the octane.
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Freshman User
Joined: Sep 2002
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Does this sound right?
I've been running 87 octane fuel, I use to run 89 all the time but since I commute to college which is about 45 miles from my house that extra $.10 started putting the hurt on my wallet. I never checked my mileage while running the 89 octane, I think I may fill up with the 89 next week and see if I get any better mileage, I know I did get better performance with the 89 octane. Well anyways, thanks for the replies guys, it always nice to hear how other people's rigs work for them. Anyone else have any personal experience to tell me about? I appreciate it in advance.
More Turbo
Joined: Apr 2003
Posts: 729
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Does this sound right?
Hi Im new, and this will be my first post
I just got a 95 f150, 4x4, super cab, shortbed, last week. I too am very suprized about my milage. So far all three times i filled up I got a range from 11.8, 12.6, and 13.1. I thought it would get at least 15mpg range. I have a 5.0 in mine and it runs perfect. It has a AT OD trans and 31" tall tires. I read somewhere it should get from 16-19mpg. I dont understand. should I be getting better. I sure hope so. Otherwise i will be kinda dissapointed. 
I just got a 95 f150, 4x4, super cab, shortbed, last week. I too am very suprized about my milage. So far all three times i filled up I got a range from 11.8, 12.6, and 13.1. I thought it would get at least 15mpg range. I have a 5.0 in mine and it runs perfect. It has a AT OD trans and 31" tall tires. I read somewhere it should get from 16-19mpg. I dont understand. should I be getting better. I sure hope so. Otherwise i will be kinda dissapointed.
Lead Driver
Joined: Feb 2003
Posts: 8,140
Likes: 4
From: Oak Harbor, OH
Does this sound right?
yor 31" tires are what is killing your fuel milage guys, humor me and put a set of L235 75 15 and see what your milage goes up to. It take alot more power from the engine to turn the larger tires.
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More Turbo
Joined: Apr 2003
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Does this sound right?
Realy! I wouldnt think so because 31s aren't that big. What do you think I would get if I took them off. I highly doubt I will but who knows.
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Post Fiend
Joined: Nov 2001
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From: Topsfield, MA
Does this sound right?
As long as you only have 31, 32's it will improve. When you install larger tires, you raise (numerically lower) the final gear ratio which improves mileage. A little of the gain is taken away by the fact that the tires are heavier but, you'll see a small gain. Keep in mind that our trucks are a tad old. There are A LOT of items that determine what kind of mileage you get. Over the years a lot of parts are worn and they don't perform as well as they used to. They might not be in need of replacement, but add all those factors up and you'll see 3-4+ mpg less than when it rolled off the assembly line. My truck gets about 12-13 when I absolutely baby it.
Last edited by MustangGT221; Apr 25, 2003 at 12:40 AM.
Posting Guru
Joined: Jul 2002
Posts: 2,205
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From: Vancouver WA
Does this sound right?
I was shocked today when I filled up and it came out at 11.9
I'm usually right at 10. Now if I could just figure out what I did...
Here's my take on the taller tire vs. MPG issue. Theoretically, taller tires should give a slight improvement in MPG due to the effective change to the gear ratio. However, taller tires raise the vehicle, causing more aerodynamic drag and they are usually wider and heavier as well so the rolling resistance increases. Let's say you have 4.10's and 235/75 tires. Going to 31's or even 32's would probably help mileage a little by decreasing RPM's on the freeway to a more suitable range. On the other hand, if the truck has got some 3.08's and 235's, going with 31's or 32's would probably hurt mileage by forcing the need to shift out of overdrive on any kind of hill or even a good headwind. So my conclusion is, who knows, just try it and see what happens.
I'm usually right at 10. Now if I could just figure out what I did...
Here's my take on the taller tire vs. MPG issue. Theoretically, taller tires should give a slight improvement in MPG due to the effective change to the gear ratio. However, taller tires raise the vehicle, causing more aerodynamic drag and they are usually wider and heavier as well so the rolling resistance increases. Let's say you have 4.10's and 235/75 tires. Going to 31's or even 32's would probably help mileage a little by decreasing RPM's on the freeway to a more suitable range. On the other hand, if the truck has got some 3.08's and 235's, going with 31's or 32's would probably hurt mileage by forcing the need to shift out of overdrive on any kind of hill or even a good headwind. So my conclusion is, who knows, just try it and see what happens.
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Freshman User
Joined: Sep 2002
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Does this sound right?
You're right pfogle, the tire size is what's killing us. My truck had 235/75/15's on it when I first got it and it got great fuel mileage, I never checked it because it did not worry me. I know that I could get close to 300 miles on my front tank, now I can only get around 200 miles before heading for the gas station...really I should be able to get 235.7 miles out of the front tank since it's 19 gallons and I'm getting 12.5mpg.
I've thought about putting the 235/75/15's back on until college is over but I hate to go from my 32's and 589's to the stock wheels and tires since they look like S***!
I've thought about putting the 235/75/15's back on until college is over but I hate to go from my 32's and 589's to the stock wheels and tires since they look like S***!
Posting Guru
Joined: Dec 2002
Posts: 1,297
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From: Billings MT
Does this sound right?
The difference in 31's and the 235/75's is just over 2" in height.
Where the difference comes is not necessarily the change in rear end ratio, but the fact that it takes more power, therefore more fuel, to rotate something bigger. You have more mass on the end of the driveshaft.
You've all also gone to wider tires, therefore you have more rolling friction with the pavement, another pull on the motor.
Where the difference comes is not necessarily the change in rear end ratio, but the fact that it takes more power, therefore more fuel, to rotate something bigger. You have more mass on the end of the driveshaft.
You've all also gone to wider tires, therefore you have more rolling friction with the pavement, another pull on the motor.