Gearing for 35's
 

I had a few questions about gearing for 35's. I currently have 3.73 and wanted to switch to either 4.10 or 4.56. I wouldnt mind dropping in the 4.56 set but I am concerned about highway cruising. Any experience out there???

I've read that it isn't worth the $ changing from 3.73 to 4.10. It's not that big of a difference to justify the cost. I think that with 35" tires, 4.56 seems to be a popular choice. I have 4.56 with my 33" tires. My RPM's are a little higher then I would like but I did my gears knowing that I plan to switch to 35" tires.

I would say 4.56 if you were going to spend the money. There are many members who are running 35s with 4.56s. I went with 4.88s with my 35s and I really wouldnt want it any other way. My truck is not a daily driver though. I think most guys say the truck feels better than stock with 35s with 4.56. Im sure they will let you know shortly.

i just picked mine up from the shop today. ive got 35's with 4.56's an it runs great. RPMs werent much higher than stock.
i also have an xcal2 from troyer...dunno if that makes any diff or not.
id say 4.56 aswell tho

I drove my truck for a year with 35's and 3;73, Got a toybox and had to put 4;56. MPG did not change as so many think, And now I don't have to down shift to pass someone. All I can say is JUST DO IT!

with 35" 4.56 will put you close to your stock RPM within 25-50 rpm of your stock tires, good luck

I say go with the 4.56's, I just got mine today and the difference was like night and day. It's awesome.

I got 35's with 3.73 gears. I also have TP xcal2 and 3.5 AF1. Everything seems fine, but seeing how most people say 4.56. What is the advantage of going with the 4.56. My rpm's don't seem too bad. Even my take off from start isn't too bad, I can't spin tire from a stand still, but that's a good thing I guess, don't want to be burning all that rubber. Although I would like to lay some rubber if I wanted too. Would the 4.56 give me more take off torque? I don't do too much stop and go. It's mostly 2 lane road top speed varies, but I do, do highway driving too. Also does driving the truck(2005 supercrew 4x4 5.4) with the 3.73 gears and 35 tires hurt anything. I plan on keeping my truck for a while and don't want to hurt anything by not having enough gearing.

Here is a good chart that should help you out... thanks to 4-wheel parts.

http://www.4wheelparts.com/gear_ratio.html

Hmm I'm confused with that chart. Wouldn't less RPM's give u better gas mileage? My RPM's at 65 is only about 1800, at 75 it's about 2000. My gas mileage is roughly 14mpg(13.76 on average). So if I was to regear and go from 3.73 to 4.56 would my gas mileage go up or down, and what about power. What's the difference in driveability in the city and on the highway.

My bro-in-law and his buddy have two nearly identical trucks on 35s.
2005 F-150s with 5.4L, cat-back exhaust.

Key difference:
Bro-in-law has 3.73s and a programmer
His buddy has 4.56 gears and no programmer

His buddy's truck smokes his truck.
And when pulling the toy hauler, my bro-in-law borrows his buddy's truck.

My bro-in-law's truck didn't feel like a dog until he drove his buddy's truck...he's going to get re-geared any day now.

Many people report unchanged or slightly imporved MPG.
I went from 3.31 to 4.10 on street tires and noted no change im MPG.

Consider that with taller gears, you are into the throttle more heavily when acellerating or going up hills.
A few hundred RPM makes a noticable difference in power, but generally a small one in MPG for a heavy truck.

The gears would help your city mpg. Basically helping turn them big ole tires easier. The higher rpm's will hurt highway mileage slightly. IMO these trucks can handle running at or slightly above 2000 rpm's with no problems. Running anything constantly over 2600 rpms' may be bad though. I took mine on a trip to FL from Maryland and averaged 16 - 17 mpg averaging 75 - 80 mmph I'd say. That's with my 4.56 gears and 33" tires too.

So is the RPM's the only problem with highway driving. I mainly do 2 lane driving, not alot of stop and go. Some city and some highway. I do travel on the highway on about 200 mile trips one way about once a month. Would the 4.56 benefit me u think.

Does anyone know of a good site to look at for gears. And do the 04's have the 9.75"?
Thanks

DANG i need to regear i have 3.55 with 37 i only get 10 city 10.5 highway. if im lucky