I just bought an 02 F150 Crew 4WD 5.4L. It already has a RCD (was told 5") lift with 16" wheels and 33" tires. I am wanting to go with 35" tires and contemplating on keeping the 16" wheels or going with 18's. I don't know that much about gears, I don't even know what I have now. I just have been looking in past threads and notice some people say to change the gears when going to bigger tires. This is a daily driver with highway driving (only 20miles a day) and mild to little offroading. My performance upgrades are Airraid intake and Flowmaster exhaust and plan on buying a Jet chip. It already seems like the truck doesn't have much power (I'm assuming cause of the lift and stuff). My previous truck was a 04 Titan 2wd with same performance upgrades minus the chip and was pretty quick. Sorry for the lengthy post and would appreciate the help. Thanks

 

Well are you pretty much set on your lift height and tire size? Or do you plan on going bigger?

If you are gonna stick with 35's then go to 4.56's this will hurt your Highway MPG SLIGHTLY but help alot in the city. stop and go traffic.

if you want to go to 37's or 38's then go ahead and get 4.88's this will hurt your highway MPG with 35's but help ALOT in the city and offroad. Then when you get 38's you will still have some power on the ground.

 

the general rule: 35's: 4.56
37-38's: 4.88

if you're sticking w/ the 35's and offroad frequently, i would personally opt for the 4.88 over 4.56. several members have run 4.88's and 35's for awhile w/ good results.

 

I'm pretty set with 35's and not going any bigger with lift or tires. So is it a definite to upgrade gears when I get the 35's or will my stock gears work? Anyony know what my stock ones would be? My offroading is very little.

 

whats your stock gears? go to your door jam and look under axle and see what the code is. if you tell me that i can tell you what gears you have.

stock gearing will work. But if you want to upgrade you wont be disappointed.

 

you dont have to. a lot of people run stock gears and 35's. but you will get better performance if you do the upgrade

 

did you get that axle code?

 

I would reconsider that Jet chip. Read up on custom tuning.

 

I have been thinking about changing out my 355's for some 410's. My setup is 01' Sup. Crew, 5.4L, Auto, 355 LS with a 285/60/18 tire = 31.46" tall. I drive about 20 miles on the Highway everyday. And no off roading at all, my beast stays on the street.

 

definitely look at the 4.10 gears
Your rear axle is a 9.75 if you have 4x4 then your front axle is an 8.8r you will need 4.10 reverse cut gears for that

 

How much more on the Gas Milage decrease, -2 gallons per mile or what ?

 

the mileage difference between your stock 3.55's or 3.73's and upgrading to 4.10's wouldnt be much at all.

With stock tire you MIGHT loose alittle mileage on the highway when not towing. But in town you will gain several MPG more.