4.10's for over 30" tire for sure. I used to run 4.10's on a 27" tire for years.

On your combo, in OD, with 60e trans and 30.5" tires
70 mph will be 2462 rpm with 4.56
70 mph will be 2321 rpm with 4.30
70 mph will be 2213 rpm with 4.10
70 mph will be 2105 rpm with 3.90
70 mph will be 2013 rpm with 3.73
70 mph will be 1846 rpm with 3.42
70 mph will be 1744 rpm with 3.23

200rpm spread at 70 mph between 3.73 and 4.10 gears.

I will be doing 3.90 gears on a 28" tire for a 2293 cruise at 70 next time I do gears.


peace
Hog

 

I'm running 4.10s w/ a 28" tall tire/wheel combo. RPMs @ 70mph yield consistently 2200 - 2300 RPM. Hwy mileage yields 17.5mpg @ consistent highway speed of 70mph. City? I have no idea. Too tempting to ease off (or into) the throttle.

 

If you haul a trailer get 4.10s for the added low end. I drive 100 miles a day and I'm going 4.11

 

I have 3.73's with a 27" street tire, 26" drag radial. Depends on what you want more of, mileage or acceleration. Its probably wiser to error with more gear, i.e. 4.10's. With a 30.5" tire and 4.10's, mileage won't be that bad, you might feel the 3.73 won't be enough gear.

 

If you plan on staying NA or tow trailers go 4.10
If you think forced induction is in your future, stay 3.42 or go 3.73

 

I have 4.10s in my truck now. Sometimes it still feels like it needs to be 4.30 or 4.56. On the highway though, I don't want to sacrifice any more RPMs.
Everyone does the calculations at 70 but in Houston, you are either going 20-30 in traffic or 80 when its free. I don't like seeing my cruise RPMs around 2500.

However, you will feel like you wasted money if you only go from 3.42 to 3.73. That swap is not worth the cost.

 

4.10s and never look back.

 

3.90s would put me right at 2000 rpms @ 70 mph. I think that's perfect. Everyone says go 4.10s but I don't think I want my highway rpms that high! Also, with the 6.0 it might be useless off the line with 4.10s!

 

I have 3.73's and a 31" tire, I'm at about 2k at 75mph, if my speedo is spot on. If I had the cash, I'd do 4.10's front and rear and a trutrac.

 

ok iam starting to lean on the 4.10s you know what they say GO BIG OR GO HOME, i dont want 2 upgrade and want more, right know i have stock 3.42s, whats all going to change acceleration,mpgs,RPMs,what else?... is it a dramastic change this is my DD and iam going do a VA to TX trip again soon i averaged about 24.5mpgs highway is going to change much? i already ordered a true trac just waiting on gears, thanks everybody. for the input.