Epic Adventure Outfitters talks re-gears

[MSFTMatt]

I like these guys and I think they have good knowledge with building out Jeeps. I found it worth watching.

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[Bandit’s Lair]

They have a vlog type thing. They have some pretty good discussions about a variety of subjects.

 

[JTdiRtyD]

I've been looking at 4.56s or 4.88s for the diesel. Leaning towards 4.88s because I'll be on the heavy side and I tow a bit in the mountains. I figure being a little over geared would be better when towing.

 

[MSFTMatt]

I just put deposit down for 5:13 for my gasser

 

[caryt]

I've been looking at 4.56s or 4.88s for the diesel. Leaning towards 4.88s because I'll be on the heavy side and I tow a bit in the mountains. I figure being a little over geared would be better when towing.

I would look at 4.56's if you stick to 37-38's.
Good site to compare gearing.
Gear ratio calculator

 

[spanishmack]

I would look at 4.56's if you stick to 37-38's.
Good site to compare gearing.
Gear ratio calculator

Ahhh! Too much word and number. Hurt Grog brain. Just want know what gear make Jeep go good.

 

[JTdiRtyD]

I would look at 4.56's if you stick to 37-38's.
Good site to compare gearing.
Gear ratio calculator

Yeah I've heard good feedback for both. 4.56s will sit around 150rpm higher than stock at 60mph, 4.88s will sit around 250rpm higher. Marginal rpm difference but a little added mechanical advantage. The truck will be heavy to begin with, then adding another 2-2500lb trailer I think the 4.88s would be more beneficial. If I wasn't towing I'd say 4.56 for sure.

 

[caryt]

You may want to recheck your math. @60 with 3.73's and 37's rpm is 1301 with 4.56 its 1517. 4.88 would be 1702. Granted if your speed is going to be max 60mph towing then the 4.88's would be better in 8th gear. I'd rather have the ability to cruse at 70mph and down shift to 7th or 6th for the mountains if needed.

 

[JTdiRtyD]

You may want to recheck your math. @60 with 3.73's and 37's rpm is 1301 with 4.56 its 1517. 4.88 would be 1702. Granted if your speed is going to be max 60mph towing then the 4.88's would be better in 8th gear. I'd rather have the ability to cruse at 70mph and down shift to 7th or 6th for the mountains if needed.

I'm comparing to stock, not to 3.73 with 37s. Back to stock rpms "should" be your goal for a highway driven rig.

8HP75
3.73s on 33's runs 1458rpm@60mph (stock)
4.56s on 37s runs 1590rpm@60mph - +132rpm from stock
4.88s on 37s runs 1702rpm@60mph - +244rpm from stock

I also don't see why 4.88s would make cruising at 70 an issue? Sure it's a tad under 2000rpm which doesn't help fuel economy, but neither does a heavy rig or towing a trailer. And while towing you really shouldn't be trying to run at 70 with a Gladi anyways.

I'm looking at what I experienced with 35s and 3.73's towing my trailer. It would bounce back and forth between 7th and 8th in the flats. Sometimes it would hold 8th, but most the time it wanted 7th.

4.56s will put me about the middle of the road in rpms between what 7th and 8th is with 3.73s and 35s. Might still see gear hunting, but probably not.
4.88s will put me a little higher, but not quite what 7th is with 3.73s and 35s. Should hold 8th no issues.

The other side of this is wind. It's rare that it's calm anymore, so the little extra gearing will help against headwinds where I would typically see 6th to maintain speed.

I've talked to folks who are happy with both, with most saying 4.56s if you don't tow, 4.88s if you do. Either route I don't think is going to be bad, and I'll make the final decision when the time comes to bring it to the shop.

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