Drive shaft

[JeepLab]

I don't like getting passed either...

I like going fast too, the more I think about it, the more I want a high cruising speed, it is about 2,100 miles to Moab from here in Maitland, Florida.

What speeds are you talking about cruising at?

What speed is possible with 4.88, 4.56?

Will one or the other or both give me enough grunt power for climbing and wheeling?

Or since it is going to be in 4 low it wont matter?

Again, I'm totally new to the gearing.
Thanks again,

Study the truth about gears thread. There is soo much in there. Here is the short answer -

I consider "cruising" to happen at 2500 rpm or less. This is where your truck will drive without you flexing your leg to press the gas pedal to maintain speed. This is how I can tell how awful long distance would be being over geared. Driver fatigue would set in. with 4.10s, i would do 5 hrs at a clip and still be ready to continue, BECAUSE she would effortlessly cruise at 75 mph in the low 2k RPMS

with the 4.88 Gearing and the 37 inch km2s, Betty would spin close to 3k to maintain 70 mph. So it was a drastic loss in cruise for me. Keeping my foot on the gas to maintain highway speed made me want to die.

Changed again to 4.56 and lost some of the pure crawl of the 4.88s. but she can cruise at 70mph at about 2300 rpm, so at 2500 im at about 73mph. And I can live with that. Acceleration is better, and crawl is better than 4.10s, but without completely turning betty into a pig on the highway.

[2me]

Thanks JeepLab, I'll re-read the Truth About Gears now that I know a bit more.
It will be more relevant.
Thanks again!

[2me]

JeepLab,
When I do get a supercharger/turbo, does this change the desired gearing?
Thanks

[JeepLab]

JeepLab,
When I do get a supercharger/turbo, does this change the desired gearing?
Thanks

YES.

thats why i say to do the forced induction mod first. Same way if you dumped a v8 into your rig, the power vs gearing would be different.

Perfect gearing without the SC or turbo, becomes OVERGEARED when the SC or turbo is added.

[2me]

"Perfect gearing without the SC or turbo, becomes OVERGEARED when the SC or turbo is added."

Hmmm,
I am already ordered the Metal Cloak 3.5 lift with the six pack shocks plus the full wrap fenders & bumpers.
A pretty big hit.
I probably won't be able to do the super/turbo for 6-9 months... Or longer.
So I'm still stuck which gear to get for the Nitto 37" aka as 35" in real life.

3.21 = 1,791 rpm @ 70 mph - out
3.73 = 2,081 rpm @ 70 mph - out
4.10 = 2,288 rpm @ 70 mph
4.56 = 2,544 rpm @ 70 mph
4.88 = 2,723 rpm @ 70 mph - out

So in your opinion will the 4.10 or 4.56 work well in the non super/turbo charged 3.6 ?
As well as
Super/turbo charged 3.6 with 37" / (35" actual ) Nittos ?

I will end up supercharging with RIPP or Magnuson or turboing the 3.6 depending how the Prodigy comes through.
I'm in a quandary since I am already committed to the Metal Cloak lift & full wrap.

JeepLab what are your gears now that you are supercharged with 37" tires?

[WhiteRavenRR]

Try using a tuner in the meantime. It won't be as effective as regearing but it will be cheaper for the here and now. Plus you can recover some of your cost later by selling it when you are ready to regear and/ or SC.

[2me]

Try using a tuner in the meantime. It won't be as effective as regearing but it will be cheaper for the here and now. Plus you can recover some of your cost later by selling it when you are ready to regear and/ or SC.

Thank you, great idea!
AEV Pro?
Other brand?
Thanks again!

[JeepLab]

"Perfect gearing without the SC or turbo, becomes OVERGEARED when the SC or turbo is added."

Hmmm,
I am already ordered the Metal Cloak 3.5 lift with the six pack shocks plus the full wrap fenders & bumpers.
A pretty big hit.
I probably won't be able to do the super/turbo for 6-9 months... Or longer.
So I'm still stuck which gear to get for the Nitto 37" aka as 35" in real life.

3.21 = 1,791 rpm @ 70 mph - out
3.73 = 2,081 rpm @ 70 mph - out
4.10 = 2,288 rpm @ 70 mph
4.56 = 2,544 rpm @ 70 mph
4.88 = 2,723 rpm @ 70 mph - out

So in your opinion will the 4.10 or 4.56 work well in the non super/turbo charged 3.6 ?
As well as
Super/turbo charged 3.6 with 37" / (35" actual ) Nittos ?

I will end up supercharging with RIPP or Magnuson or turboing the 3.6 depending how the Prodigy comes through.
I'm in a quandary since I am already committed to the Metal Cloak lift & full wrap.

JeepLab what are your gears now that you are supercharged with 37" tires?

Im at 4.56 now.

4.10 is good too. Sweet Pea is the Magnuson truck. We are about to bring her to 37"KM2s also, She will stay at 4.10.

Jesse's Girl, Our MetalCloak, soon to be TURBO truck, has 4.88s in it now. So we are going to have a forced induction model, WITH 37" KM2s at each gear level. 4.10, 4.56, 4.88

My money as usual, is on Black Betty's setup. It may end up being moot, as Betty's power is a little higher up the RPM band than Sweet Pea, the 4.56s will keep betty's power band spinning a little faster than the mag with 4.10s. Mags power starts lower, so that should even out.

Jesse, with 4.88s, I think made the mistake of changing gears before forced induction. I think she will end up over-geared. I told him not to sell the 4.10s he took out. He is driving 4 hours to get here, so on the way back we will find out if he wants to pull his hair out with the turbo limited by that gearing....

with 4.10s he could cruise at 90.

[2me]

Im at 4.56 now.

4.10 is good too. Sweet Pea is the Magnuson truck. We are about to bring her to 37"KM2s also, She will stay at 4.10.

Jesse's Girl, Our MetalCloak, soon to be TURBO truck, has 4.88s in it now. So we are going to have a forced induction model, WITH 37" KM2s at each gear level. 4.10, 4.56, 4.88

My money as usual, is on Black Betty's setup. It may end up being moot, as Betty's power is a little higher up the RPM band than Sweet Pea, the 4.56s will keep betty's power band spinning a little faster than the mag with 4.10s. Mags power starts lower, so that should even out.

Jesse, with 4.88s, I think made the mistake of changing gears before forced induction. I think she will end up over-geared. I told him not to sell the 4.10s he took out. He is driving 4 hours to get here, so on the way back we will find out if he wants to pull his hair out with the turbo limited by that gearing....

with 4.10s he could cruise at 90.

JeepLab,
I'm real interested in seeing how Sweetpea will run with 37's & 4.10's and the Magnuson SC.
I'm looking at Magnuson, RIPP or Prodigy in about 6-9 months.

[JeepLab]

JeepLab,
I'm real interested in seeing how Sweetpea will run with 37's & 4.10's and the Magnuson SC.
I'm looking at Magnuson, RIPP or Prodigy in about 6-9 months.

I think we have a long arm planned for sweet pea. As soon as we get it installed ill beat up pete to get on here and give you all a first hand account.

I can tell you now how it will drive... Fast. Powerful. Betty was plenty fast with 4.10s and 37s. Sweet pea has a TINY bit more low end grunt. Keep in mind, all our trucks are manual trans. So auto may differ.

With 37s and 4.10, she will stay fast, as we will pick light wheels for her, and obviously the km2 is the lightest 37 available. 1st thru 5th will be speed gears, 6th will be a highway cruising gear. She will cruise at 80 MPH at about 2500 RPM in 6th gear. This gear set up is OPTIMAL for long distance driving. WHILE the Rubicon's 4 to 1 transfer case will keep her agressive off road.

At 2500 RPM BB cruises at about 72 MPH with the same tires and 4.56 gearing.

When picking between the 3 power mods, there are pros and cons to each, AND your driving style will come into play also.