My 255's are ready to be replaced. I keep going back and forth with trying to decide whether or not to stick with 255's or go up to a 265/75/R16 tire. What or how much of a difference in performance and gas mileage did you guys that made this switch notice. I don't want to kill my performance, I can deal with a slight loss but not a huge one. My current setup is a 1997 F150 4x4, 4.6 V8, Automatic Transmission and 3.55 limited slip differential. I guess I'm just looking for some last minute input before I make my final choice. Any help would be GREATLY appreciated.

 

You are changing the gearing by 5%, so you'll have at least that much against you. The extra weight of larger rims and tires also has an effect. Will you notice? No one can tell you.

 

My rim size will not change, I unfortunately had a typo in the title of this post and have not been able to correct it. I am debating between 255/70/R16's and 265/75/R16's.

I keep reading different things in different posts. Some say no noticeable difference others say it's a huge difference. I guess seat of the pants feels is more of an individual thing. But, how about gas mileage (which is what I'm mainly concerned with) has anyone been keeping track of there gas mileage before and after the switch once there speedometer was corrected?

 

Still 5% difference is tire size.

As for fuel mileage effects, again it depends on how you drive. If you are more agressive with the accelerator pedal, then you'd be dipping into it even more and using more fuel. If you are less aggressive, then you won't use as much extra fuel.

FWIW, I have a 2003 Screw, 5.4L, 3.73 gears with the 285/70R17 tires. I get about 13mpg.in mixed driving. If you cna live with that as a worst case, then go for the larger size.

 

I ran 265's on my 97 4.6 f150 4x4 for nearly 50k and hardly noticed a difference in performance or mileage. I now run 285's, and with the flowmaster installed the power loss is gone. With the 265's I got about 14mpg in the city and believe it or not, 17-18 on the highway with 3.55 gears. I get about the same with my 285's thanks to the exhaust. Between the 255 and 265, I'd go with the 265, but the 285 makes the truck like yours look the best.