I'm back again. I have the 1998 F150 4x4 that needs a little more get up and go. I've gone from a 255 tire to a 285 tire. I've added a superchip, exhaust and K&N kit. I was told to either go back to original tires or get new gears. I like the tires so I'm saving money for the gears. The shop that comes currently have the 3.55 gears. I've added a highly recommended says I should go with the 4.56 instead of the 4.10. What do you think? Whats the mileage difference between a 3.55 and 4.56? Or the difference between the 4.10 compared to the 4.56? Please let me know.

 

Wow what a change form stock. 4:10 is pretty low and 4:56 would be useless on the highway. But wait..........you need to figure out what gear raito you end up with thoes tires. There is a formula. I know what I would do but its not my truck. Good luck and treat that truck well.

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97 F-150 4.6 auto, 4x2, 3.55 LS, WMS Velocity tube, K&N, Dynomax Super Turbo exhaust with Echo tube.
Oh yeah, it's Oxford White with crome wheels, Legacy shell & custom grill!

 

I have the 4.30 LS and 2000 RPM moves me along at 57 MPH in OD.
My tires are LT265R70x16.
I think a 4.56 might be too low for anything but hole-shots.
Good Luck.

 

If you go with the 4.56 ratio, you'll probably have to get SuperChips to do some serious reprogramming for you if you have an auto tranny.

I think your truck still uses a gear in the speedometer sending unit, so you'll need to check with Ford to see if they have a gear that will match your setup. I'd suggest you check on that before you go to the 4.56 gear.

 

Hopefuly I can get some bites with this line.

I have an '05 FX4 and would like off the line power, but don't want to sacrafice the MPG. Should I go with an 4.10 gear?

So what do you think?

 

what gears do you have now? what's your axle code if you don't know your gears?

YES, the 4.10's will probably improve your town mileage a bit and highway should stay close to the same

 

New gears for 4wd is about $1200-1500 installed. In addition to finding out what your stock gears are, tell us what tires including size you have.

 

I have 3.73s and the tires are 275/65-18. I am going to do a slight upgrade of a 285/65-18. Also, I am changing wheels (idk if that matters). I have no idea what the axel code is. Yeah, i've been reading that the 4'56 will have too much whining at hwy speed and the rpms will really go up.

 

3.73->4.10 is not enough to justify the change. If you want more power and are going with larger and heavier tire/wheel combo, then you want 4.56.

 

I am not going to a heavier tire/wheel combo. I am pretty much staying the same.

 

This is not correct. I changed from a 3:55 to a 4:10 and it cost me at least 2 miles per gallon. And I am very light on the pedal. I drive 60 on the Istate and 50 in a 55 zone. Around town it drinks the gas and I am not holeshotting it. I used to average about 15 to 16 mpg driving the same way I do now. Not it is 13 to 15 depending on how much highway driving I do.

Steve

 

If you dont mind me asking what size tires do you have?

 

when is the last time you changed your plugs? what mods are done to your truck besides the gears? do you tow much?

 

This is with stock size tires and not pulling anything. I have new plugs in it now, but that change did not make a bit of difference. My only performance enhancement is a Edge Evo. I use the Tow mode because I tow a lot. I did gain mileage when I had the 3:55's and added the Edge.

I am saying that changing to a lower gear will not make your mileage go up. I use the Instant Mileage on the Edge (a glorified vacuum guage) to help me keep my foot out of it.

Steve

 

If you are going from a passenger load rated tire to a light truck load rated tire, you are increasing tire weight by almost 50%. The BFG AT in 285/65R18 weighs 60 pounds vs. OEM tire somewhere around 42 pounds. Go 4.56 or stay with stock gears.