I really lost my interstate power. I have heard that 265/75/16's are the same diameter as the 17" Offroad package, so I thought I would be equal to one of those with my 3.55 gears. Anyway, around town it feels the same. I noticed it on hills on the interstate the most. I lose 10 mph on some hills now , and before the change I lost about 5-6. Truck looks a lot better though. I went with Kelly Safari AWR's 4 ply. They were $373.08 total. I sold my stock Generals to a coworker for $150.00, so I dont have much in these. I'll end up with a Flowmaster, modified airbox and a Superchip to compensate.

 

I would have to blame the 6ci for that... Try some underdrive pullies. They work awsome.

 

dave, I would have to agree with the 6cyl being the culprit , I did the same thing with my 4x4 supercrew 5.4 and didnt notice any difference at all and I tow a flats boat everyweekend. The chip will help you greatly with this . In fact I am considering putting 285's on now. So if anybody is interested in a set of 265 17 16 BFG AT KO send me an email.

 

I used to have a 99 F150 SC 4x4 and I put 265x75x16's on it...it originally had 235x75x16....the same result

Poor power on the highway, and I lost about 2 mpg!!!!!

Now have a 2001 Screw with 255x70x16...going to go to 285's after a 3" body lift....I am better prepared with a Flowmaster, Superchip and an AirAid already installed...LOL

 

davidzog,
Just curious,why are you putting a 3" body lift on if your only going to 285's.

 

Dave Tabata, Davidzog.....did you get the computer reprogrammed when you went to larger diameter tires, it may make a difference.

Dave Tabata....didn't think Ford had a 4x4 with the 4.2L, at least not back in 1999 when I got my 4.6L 4x4 XLT?

I plan on getting 265/75R16's this spring, but plan on getting the computer reprogrammed.

 

Yes, Ford does make the 4X4 with the 4.2. Most XL 4X4's I have come across have been the V6. The only thing getting the computer programmed would have an effect on (short of an aftermarket chip) would be the speedometer. Mine is a 5 speed and I am off approximately 3 - 4 mph at 70. I am going to save the $70 for the recalibration a local dealer charges and put it toward a Superchip hopefully this summer. I may have been a bit hasty on my post about losing great interstate power. My truck actually feels stronger at speeds below 60 and just a tad slower on the interstate. Of course downshifting solves it anyway. I can still get a good second gear chirp.