i have a 2001 screw4*4 4.6l 5spd ,, with a current gear ratio of 3.55 ,,,,,,,and am looking to going to 4.10 ,,,,,,,what would change ,
would i get better torque off the line???
Loose top speed ,
and gas millage??????

 

Yes you get more off the bottom. You loose top speed and you can loose gas mileage. That depends on if you are changing it for performance or if you have to. Such as if you have larger tires.

 

It's just because i would like to have 33" tires , and wanted to know by doing that ,,,,,would i need to change my gear ratio or for 33" ,, is the 3.55 ratio alright

 

changed my 3:55 to 4:10 after i bolted on my 35's. i did the calculations and determined i actually needed a 4:28 which they dont make. a 4:10 gear with 33's will get u close to the original factory gearing

 

thanks for the tips ,,,,,but would the 3.55 gear ration be good enough for 33's , cause i think i've seen it before??

 

Hugs,
Dont bother with thinking that you can get buy with 3.55's with 33 inch tires.

I have 33's on my 97 150 SC 4x4 and the 3.55's with the 4.6L just aint to whippy.

I plan to make the move to 4.10's also.

Just a little FYI.

 

Thanks for the tip LakeNut
But is it that bad with the 3.55 ,cause my truck came stock with 255's 70R 16's ,, and if right that's pretty close to 31"s ,, so going to 33's would make that much difference

 

I have the 5.4 that came with 255/70-16. When I put 285/75-16's (which are almost 33") on it it lost a lot of power. It would even ping on hills. I put 4.10 gears and it is as good as ever.

 

hugs,
As far as your tire diameter goes, a 255/70R16 is a 30.1" diameter tire (just say 30 even, it makes calculations easier). For a 33" diameter, you are adding 10% to your diameter, 33/30 = 1.1, or 110%. To get things back to even, you'd need to 'up' your gearing by 10%. 1.1 x 3.55 = 3.91, give or take, which is not an available ratio. A 4.10 is 15% 'higher' than a 3.55, so with 33" tires you'd actually end up with more torque/grunt than you started with. I agree with the others, I wouldn't put on 33" without re-gearing, but we all know that they don't do that kind of stuff for free either, so it'll be up to what you can afford. Good luck!

One thing I was very curious about. You mention you have a SuperCrew with a 5-speed?? I thought they were only built with automatics. If you have a stick S'Crew, you have one rare bird. Did you mean a SuperCab? Sorry, I was just very curious. I can't believe no one else has asked this. My '98 4x2 Lariat SC 4.6 is a 5-speed, which is pretty rare in itself. Again, just wondering!!?? Take care!

 

Changing gears is way over rated. I am going to be running 37x12.50R16 Super Swamper Radials and 3.55 Gears. The 3.55 gears with my 33s runs as good as stock. I only have a 4.6 liter v8 too.

 

Yeah sorry about that ,, i ment supercab and not supercrew.
So i guess most people think that changing the gear ratio is almost necessary for 33" tires ,,,,,,,,,,,, i just wanted to know cause i've seen many post on this message board with people saying that 33" work great with their stock 3.55 ratio such as
2dollarsteak (nice truck by the way) and says it's almost good as the stock tires
I wouldn't mind going from 3.55 to 4.10 ,, but i don't really care about the torque ,, i'm often on the higway and like to cruise around 70 to 80mph,,,,,,,,,,,with the 4.10 gear ratio ,, i'd be killing my wallet on gas,, wouldn't be like 3 to 8 mpg worse.
i'm not sure i want to loose my top end speed ,,, so i might have to go with smaller tires ,,,,,,,,,,,what about 265" or 285"????
would the gears need to be changed as well

 

I have the 31.5" ORP package (265/70-17) and I switched to 4.10's. My truck runs great now. Huge difference in real world power. Don't let anyone tell you that changing gears isn't worth the money. No noticable difference in the gas mileage.

2dollarsteak - I think you'll change your mind on gears when you get those big tires. If I went to those, I'd be getting 4.56's.

Ian

 

So Ian N you've changed your gear ratio and you don't have that much difference in mpg,,,,,,say at 60mph ,,,,,,,how many RPM's is your engine doing?? and what were your rpm's before you changed your gear ratio.
Cause i know the tires will make a little difference ,,,,, but i thaugh the gear ratio would really have an effect on the gas millage.
You gained some torque for sure ,,,,,but what about your top speed ? have you lost alot?

 

At 100km/h (I see you are a canuck too) I am turning ~2100rpm with my 31.5" tire package. Before was about 1800. Since the torque peak is at 2400, I am closer to the peak on the highway.

If you take your current (3.55) revs at any speed and multiply by 1.15, you will get the revs with 4.10's. For 4.56, multiple by 1.30.

I have a chip that removes the factory top speed limiter so as far as top speed goes, at redline (assume 5000rpm) that would give me 240 km/h, so I would be limited by aerodynamics, not gearing. There is no way an Expy could do that without a blower.

The highway performance is fantastic with these gears - roll-on power and hill climbing is awesome. I made the change to help in towing my trailer but I am happier all round.

 

So being closer to your RPM peak probably actually makes it a little bit better on gas???
It's great that your a canuck to , cause i've been looking for pricing on that to in cdn$$ ,, and was curious on how much it would cost changing from 3.55 to 4.10??
Does Ford offer a 3.73 ratio??