Why have u stayed stock????

 

Your rims are 17" not your tires....right??
Also increasing gear size will help out in lower rpm's and taking off it will also eat more gas. Unless u are are increasing ur tire size and lifting it is an inordinate cost and not economical. If u switched down and replaced your gears with higher gears in the 2 range ur fuel economy would increase and your pulling power, these gear sets are often refered to as highway gears.

 

Thanks everybody for your input. Still not sure what I'm gonna do.

 

Yea changing from 3.55 to 3.73 really isn't worth it, I will only do it if I go to 4.10's. In response to a tire change to get the gearing of 4.10's the tires would have to be tiny, and ford puts small enough tires on the trucks to begin with.

 

I Just Checked My Mileage After My 3.55 To 4.10 Swap, 1 Mpg Better Than Before. I Guess It's Better Than Losing Ground.

 

AAA, When you go to a numericly lower gear, or as you said highway gears i.e. 3.55 to a 3.08 you lower your rpm's at any given speed but you dont realley gain any fuel economy because your engine has to work harder to push the truck at the same speed, by doing this you have effictively dropped the engine out of it's torque range. Same as putting bigger tires on it without a gear change, most times you lose mpg and your "pulling power" definately dosen't increase it is decreased.

 

How do the different gears affect your gas mileage?

Robert

 

question which is better 3.73 or 3.55, according to the door code I have 3.55 2000 F150 4x4 super cab.

Thanks

Lance

 

I agree, you will see very little differance from 3:55 to 3:73. If your doing the job yourself, after all the time and sweat the 4:10s will be worth it but not the 3:73s.

 

I have 3.55 and i would like to change it to 4.56. any ideas on where and how much parts are for this. Also i would like to make the rear either a locker or limited slip but don't know where to get the parts.

 

guess it all depends on what you eant more gas milage or more touque.

Lance

 

Berto, "on paper" if you lift your truck or add bigger tires or both, then lower your gears ie. 3:55 to 4:56 you will gain back your lost power and mileage, again on paper. In reality if you do this you will gain some of it back but not all of it. You still have more rolling resistance from the bigger tires and more drag from a taller truck. I guess to sum it up... sorry I rambled from your question a bit... generally speaking A numericly higher gear will give you more power/ less mileage while a numericly lower gear will give you less power/ more mileage. Remember there are always exceptions to any rule, this is just a generalization.

 

Well, I put 305/45R22 Tires on my truck and at 75 MPH, I run at 1900 RPMs but am constantly down shifting. I think if I put different gears in, it will help. What are some recommended ratios?

 

Berto, your tires have a diameter of 32.8 inches. It would help to know a little more about your truck but I'm guessing you have 3.55's also what stock tire size you have. A good rule of thumb is one tenth on the ring gear for every inch in tire change. If you had 30" tires to start with and now have 33" tires you would add 3 tenths to your ring gear ie. 3.55 to 3.85 ther are no 3.85's so you can go up to a 4.10 (what i would do)
to help compensate for more width and lift height, plus it will make it a lot more fun between red lights. If you go with a 3.73 your still gonna be a bit sluggish, and as mentioned before 3.55 to 3.73 isint really worth the trouble. If you do a search on this site you will shurely find a lot of links to tire size calculators and ring gear to tire size calculators. Sorry this is so long, and I hope it helps you.
David

 

Thanks eveready, you have been very helpful. Yes I have 3.55 gears and I had stock 17. I have an STX and I don't remember the stock tire size. Thank for the help.