My thick skull 37 vs 35

[stretch-bsn]

Okay so I’m trying to wrap my brain around this…

Dana 44
3.73 gears
Steel C’s
Lift 2.5”


Current weight of my 35’s is 72lbs per tire

Weight of a light set of 37’s is 68lbs per tire


I sort of understand rotational mass but is it that big of a deal since the tire is actually lighter?


Saying that I’ve seen people wheel with 3.45 gears and Dana 30/35’s and 37’s but I know that doesn’t mean it’s good for any type of longevity.

Everything I’ve read says 4.88’s or 5.13’s for 37’s so I understand that’s the reasonable/smart thing to do.

Just wanted to understand better and see what some real world wheelers think.

Odds are I’ll probably go 35’s again but I’d love to throw a set of 37’s on there.

Sponsored

 

[JT1]

3.73s? Do you have a diesel?

 

[stretch-bsn]

3.73s? Do you have a diesel?

I did an axle swap on my sport…was told they were stock rubicon axles with 4.10’s….turns out they were 392 axles

 

[Mifsuud]

The increased circumference means a lot more than the weight. If the weight was exactly the same it would still be much more work on your drivetrain with 37s. I wouldnt run 37s on 3.73, especially offroad without the Rubicon transfer case.

Must be early 392, they come with 4.56 now.

 

[JT1]

I did an axle swap on my sport…was told they were stock rubicon axles with 4.10’s….turns out they were 392 axles

Ahhh, that makes more sense.

I have a gladiator on 37s, and it was miserable with 3.73s. Mine's a 6spd though. It wouldn't pull 5th gear until about 80. Running 5.13s now. If you see overdrive now with the 35s and don't mind a regear, give it a shot.

The diameter is more of a killer than weight. I have had 3 different 37s, and never noticed much penalty for weight (KO2s, Pat MT-01s and MT BajaBoss ATs) but you will 100% notice the change in diameter.

 

[stretch-bsn]

Okay…that does clear it up a bit. Honestly don’t even notice much of a difference from 3.45 gears that were in my Dana 30/35 and the 3.73 gears in the Dana 44’s. 8th gear is not something my Jeep is used to lol.

So I’ll stick with 35’s and one day when I have $2500 to drop on gears I’ll do it. Until then I’ll stick to not ruining my rig lol

 

[SadRobot]

I'm running 37s on Sport axles (D44 rear, D30 front) but re-geared to 4.88. My Jeep struggles sometimes and should really have 5.13s but I can't re-gear again until I upgrade the front axle to a D44. I can't imagine having 3.73 gears.

If you have an auto I'd say 4.88 is fine. If you have a manual I'd re-gear to 5.13.

 

[Maverick909]

100% 3.73 gears are terrible for 37's. I mean 4.10s sucked with 35's. I would HIGHLY recommend 4.88 for 37's leaves good mileage and power. still off-roadable with the sport transfer case. Ive been wheeling my wrangler on the setup for the last 3-4 years. no issues.

 

[JT1]

If you have an auto I'd say 4.88 is fine. If you have a manual I'd re-gear to 5.13.

While I mostly agree with that statement, I honestly think if you have a rubi, or swapped a 4:1 TC in, I think 4.56s with 37s would work too.. 5th gear with 4.56s is the same as 6th with 5.13s. I find running at 85mph gets me into the second stage of the oil pump.. having another gear lets me run 85 without getting 10mpg.

 

[SadRobot]

While I mostly agree with that statement, I honestly think if you have a rubi, or swapped a 4:1 TC in, I think 4.56s with 37s would work too.. 5th gear with 4.56s is the same as 6th with 5.13s. I find running at 85mph gets me into the second stage of the oil pump.. having another gear lets me run 85 without getting 10mpg.

Hmm well I guess I'll learn soon enough. I'm hoping to install my Rubi t-case by end of October.

On another note I don't think I've ever gotten my Jeep up to 85 mph.

 

[JT1]

Hmm well I guess I'll learn soon enough. I'm hoping to install my Rubi t-case by end of October.

On another note I don't think I've ever gotten my Jeep up to 85 mph.

With the manual, the deeper gearing offroad is REALLY needed.
With a 4:1 TC, you can sacrifice some axle gear and actually be able to cross an entire intersection on-road in 1st gear. lol.

 

[SadRobot]

With the manual, the deeper gearing offroad is REALLY needed.
With a 4:1 TC, you can sacrifice some axle gear and actually be able to cross an entire intersection on-road in 1st gear. lol.

I'm told with a 4:1 you can just put the Jeep into 1st and it will actually crawl up things without touching the gas pedal. That will be a first for me to see that happen.

 

[JT1]

I'm told with a 4:1 you can just put the Jeep into 1st and it will actually crawl up things without touching the gas pedal. That will be a first for me to see that happen.

My gladiator does that now with the 2.72 and 5.13s. I really only need to hit the gas to bump ledges or climb out of the water (or get a little heat in the tires). I normally run in 4L 4th between obstacles..

 

[grimmjeeper]

Hmm well I guess I'll learn soon enough. I'm hoping to install my Rubi t-case by end of October.

On another note I don't think I've ever gotten my Jeep up to 85 mph.

If you manage to get it up to 88, you're going to see some serious shit...

 

[grimmjeeper]

I'm told with a 4:1 you can just put the Jeep into 1st and it will actually crawl up things without touching the gas pedal. That will be a first for me to see that happen.

Having a diesel helps that a lot.

Sponsored