I have a 2003 Super Crew Fx4. I have an opportunity to purchase a set of BFG ATs 315/70/17s off of an H2 for $250, installed. This cash price also includes the realignment after cranking up the torsion bars.

My question is, will they fit and what should I expect them to do to my gas mileage? Normally I wouldn't be too concerned about the mileage but with the sky rocketing prices I guess I need to be.

If anyone is running this setup with or without a body lift I would like to hear from you. For this price I'm considering the body lift if it is necessary.

 

They will fit with the cranking of torsion bar you mentioned. They will cost you about 3mpg and quicker suspension wearing, though. I only have 285/70R17 BFG's and wish I had stuck with stock size. I have one tank that I got 14.2mpg, but the rest have never been above 12mpg. 16k miles thus far.

 

$250 is a really good deal. This is the first set of BFG AT's I've owned but I really like them. Good tires and they have been wearing good for the 10k I've had them on the truck.

My gas mileage has dropped about 1 from stock - now I tend to average 13.5-14.5 mpg. I do have the MicroTuner and have calibrated the tire size to 33.75", which seems to be the going height for these tires (mine are at 35 psig). I do put in 93 octane and drive pretty darn light on the throttle. I'm usually the guy you cuss at who's not accelerating fast enough from a stoplight

Anyway, you will feel a big performance decrease going with the 315s. It doesn't affect me all that much, because I drive lightly, don't tow and live in a flat area. But if you push your truck hard, you'll probably want to slap a set of gears in it to get that performance back.

Mike

 

My 315s didn't drop my mileage much, and certainly not 3mpg. At 3 mpg, are you taking into effect the change of the calibration in the speedo due to the larger tires? It may not be as bad as you think.

I cranked my torsion bars, not all the way, but some, and trimmed about an inch off the bottom of the air dam and tapered it up from there. The only rubbing I get is at the frame at full steering lock, or when I get seriously tweaked up at the deer lease.

I've towed a bass boat and several cars on a trailer since putting them on, and haven't noticed the performance loss enough to justify $1000 for new gears.

 

I have 285/75R17 (5% larger than stock, but heavier tires) and have been getting 2-3mpg lower than I expected. I cannot directly compare because I replaced the OEM tires three days after dealer delivery. However, I had a similar truck (drivetrain config) prior with 265/70R17 tires for 70k miles.

Highway towing performance and fuel comsumption are the two areas that I noticed more effect than I expected. I have not recalibrated the speedo/odo, but 5% more than 11mpg does not equal 13mpg.

My caveat - it depends on how you drive your truck. I know I favor a heavier pedal than the average F-150 owner. But, I drive it the same way I drove my last one.

Microtuner with a light foot can get 1-2mpg better, which correlates packager_jr's experience of still getting 1mpg less.

 

I'm going to go with cranking the torsion bars and trimming the air dam.

Hillbilly, do you have any pictures of your air dam after you trimmed it? I'd also like to know how many turns you cranked your torsion bars.

thanks for the help!

 

Can someone give me some information on the MicroTuner? I'm a very lightfooted driver and I average right around 14 mpg for the first 18,000 miles. I've added the flowmaster muffler and a K&N air filter hoping to squeak out a coule of extra mpgs but neither helped much. What is the MicroTuner and can it do something to help my mileage? It's my understanding that the speedometer be recalibrated by the dealership through their computer. Any information on this would be appreciated.

 

Superchips MaxTuner

Also, cehck out the Computer chips forum here with many informative posts by a suporting vendor, Mike T. at Troyer Performance.

 

Hillbilly, could you send me a pic of you pickup? I've got a 2002 Supercrew that I would like to put bigger tires/wheels on. The rest of y'all can tell me about what I'm going to get into!

Charles

 

Thanks everyone. I've decided that this is the deal for me. Now I need to arm myself with all of the information necessary to get these installed.

Can anyone provide me with more detailed information regarding the installation of these 315s on a stock truck? The guy I'm working with was told they would not fit on my truck. So, I'll be guiding him through this. Any information you could provide would be appreciated.

I need to crank up the torsion bars. How many turns?

I need to trim the air dam. Does anyone have any pictures or a detailed description? I figure I can do a much better trimming job in my garage then I can at the tire shop. My plan is to have the air dam already trimmed before I take it to have the tires installed

I'm installing these on my stock 17" ford rims. The tag on the inside of the door says that they are 7.5" rims. The H2 has an 8.5" rim. Are your 315s on stock rims?

After the torsion bars are cranked and the tires are installed I'll have the truck re-aligned.

I'm still not sure where I'll need to go to get the trucks computer recalibrated for the larger tires. Is this something that can be done by a dealer or do I need to find an aftermarket truck center?

Hillbilly, I read in one of your posts that you had these tires installed on a stock truck but had a body lift in the garage ready to be installed. Why did you go to the body lift? Did the body lift stop the tire rubbing you described when the steering wheel is turned completely?

Is there any additional information you think I should know before heading out to have these installed?

Thanks for everything so far.

 

I have an 01' F150 SuperCrew with these exact tires(315/70/17 BFG AT) on them(17x7.5 stock rims). I also was told I could raise the torsion bars without a lift. Bull!!! There is no way they would have fit. I ordered a 3" Performance Accessories Body lift and then had the tires mounted. As for the torsion bars, mine are cranked all the way. One side has more thread than the other, but I was told it came from the factory like that? I don't exactly know what the gas mileage is now, but I ride these tires @ 30psi. The tires place put 35psi, but I put 30 in hope that they will not wear uneven as bad considering they are a bit large for the stock wheel. All in all I love it the way it is and I have had nothing but good comments on its appearance and smooth ride. I plan to rotate them every 3,000 miles. I don;t have a pic of mine, but there is a post of the same set-up that "lsuscrew" has and I will try and post it for you to see. Hope this helps.

 

here is the link to the post with lsuscrew's pic. Scroll down to the green supercrew.
lsuscrews truck

 

Sorry it didn't work for you, but it did for me, it's sitting in the parking lot right now...

As for the rest of y'all that had questions, I'll work on a write up on how I made them fit, I'll have something by Monday hopefully.

I don't have the body lift put on yet, I ordered it because I'm going with a 17 x 10 wheel, and there's no way I could get those on without it.

Stay Tuned...

 

I ordered the performance accessories 3" lift on Friday. I ordered it from Jackit for $190. The 2003 apparently has some changes that requires a different kit than the previous years. If shipping runs on time I'm planning on putting it on this Saturday.

I found this review on the performance accessories installation. https://www.f150online.com/reviews/lift.html

This review is from a 1997 f150. Has anyone put this lift on a 2003? Any major differences to the install?

I'm still a new user to this site. Should I start a new thread in a different section of the site to get any tips on the body lift installation?

Thanks for all of your comments so far...

 

Did any of you recalibrate your speedometers or transmissions? If so, what route did you take to accomplish this?