kersh04

There's a 4:30 for 2wd. They don't make a reverse cut 4:30 for the front.

DavidKR

you can get an SD dually 4x4 with 4.30s. but yeah I've never seen them for an 8.8 front.

in 2013 and 2014, you could get an FX4 with 4.10s with either a 6.2L or a 3.5L. and the Tremor was only available with 4.10s which is kind of silly because all of the fastest EB trucks seem to have 3.55s and there are even a few pretty quick ones out there with 3.31s.

cbr600rx7

3.73 to 4.11/4.10 may be a larger jump then some people give it credit. For some reason people don't seem to think it's a major jump in gear ratio maybe because it's just the next steep up. But let's look at the math.

3.73 to 4.11 = 0.48 ratio Increase

4.11 to 4.56 = 0.45 ratio increase

3.31 to 3.73 = 0.42 ratio increase keep in mind we skipped right over the 3.55 that would have only been a 0.24 increase.

SteveLord

Here's some math.

+10%

+11%

+13%


3.55 (most common gearing) to 4.11 = +16%. Hence, why I went with that.

Remember, this is still a $2000+ and few days job. Add another $400+ if you don't already have a programmer + custom tune to really maximize it.

cbr600rx7

How about some feed back on your 4.11s. How do you like them and what's your set up look like?

SteveLord

I posted on page 2 initially.


So you're a 5.0 with 3.73s. I too entertained just trading to an Ecoboost since they will turn tires better thanks to the torque.

I wish there was a ~4.38 gear option (don't think there is) because it would be a nice sweet spot.

blue5.0

This may not be applicable to this discussion but going from 3.73's to 4.10's on my 95 mustang was a night and day difference. I plan on going to 4.10's in my truck this year from the garbage 3.31's

cbr600rx7

Here is a calculation of 3.73 vs 4.10s with 275/65R18 stock tires. <br/>3.73s are on the left and 4.10s on the right<br/>







Here is the same chart but with 3.74s on the left and 4.56s on the right. Still with the same stock (32.10 inch tire)

cbr600rx7

So after. Lot of research I think 3.73s to 4.10s may be a good option. With 4.56s I would be massively over geared with a 32-33 inch tire (275/65R18 currently and planing to go 285/70R17 latter)

With the 275/65R18 and going from 3.73 to 4.10 it would increase my rpms by about 200 at 65mph in 6th gear. With the 285/70R18s it would still be about 150rpms higher then stock. Not a huge change but factory in the 10% increase in gear multiplication and I think it will be noticeable.

The 4.56s would run almost 500 rpms higher then the stock 3.73s do at 75 mph. If I went to a 35 inch tire that I have no intention of ever running it would still be 200 rpms higher then stock.

I found a highly recommended old man who does nothing but axle work a few hours south of me. And here is what we came up with.

New front and rear 4.10 gear sets from Yukon
New front and rear bearings, seals, install kit, and fluid.
Front Limited slip upgrade (still researching eaton and ford)
Installed with labor and parts $2100 out the door.

That doesn't sound to bad especially if I gain a front limited alip diff in the process and a little extra gearing.

cmbowles25

Don't forget to factor in the weight difference and the higher rolling resistance that comes with larger more aggressive tires. I went from 3.55 to 4.10 with 33" tires. I would have gone 4.56 if ford made those gears. I wanted to stay with oem parts. If a company would start making a 4.30 for reverse cut 8.8 that would be the ticket.