3.73 gear ratio based on what tire?

[Zachanadandy]

Was the end goal of the original question simply to know which trims have 3.73 (which was answered in the middle of all those posts) or was it a question of optimum differential ratio for a given tire diameter (which is a loaded question that cannot be answered except as personal opinion)?

The way it's worded, it's a if he knows you can get all 3 tire sizes with 3.73s, but wants to know which tire size "actually" has 3.73s? All 3 as he knows. I'm assuming he wanted to know/assumed that the smallest tire is optimally matched to 3.73s, but as you pointed out that's a loaded question subject mostly to personal preference.

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[Banned]

The first half is correct. Tire size is completely irrelevant to gear ratios.

A 4.10 ratio is for every 1 rotation of the axle, the engine spins 4.1 times. It doesn't matter if there's a 31" or a 40" tire on that rear end, those relationships will not change. The difference will be how many times a 31" tire will revolve over the same distance versus a 40" tire. And that will affect the RPM/Speed ratios.

Lol, it has absolutely nothing to do with engine speed. 3.73's will work well on 33" or smaller tires with a 3.6.

 

[ZeeJay]

Right, the pinion rotation; I was working on the assumption of a 1:1 ratio coming out of the transmission. My default is thinking of a 4-speed manual. JT has a final drive out of the transmission of .8 or .6 something, I don't remember.

Talking about final drive ratio is not addressing the OPs question and also adds confusion when you're not clear because final drive ratio is usually referring to the transmission final gear or the ring & pinion.

Tires can manipulate ratios, experienced by the impacts of RPMs/MPHs (fuel usage is ignored), not the actual mechanical ratios. Because tires can be swapped out easily, and also inconsistencies between mfgs in sizes, tires are a poor baseline to use in gear ratio discussions.

So when the OP asks if a tire size is how you determine what the gear ratio of a JT is, the correct answer is: tire size doesn't matter. It's mechanical pieces from the factory, unless aftermarket parts were put in, in the determination of gear ratios.

I don’t know what being asked exactly, but it would seem there is some association with tire size to differential gear ratio, which yes there is a relationship there. OEM will do the math with tire included and it would so happen 3.73 is kinda Goldilocks. Not too low but not too high either. They chose 4.10s for other models for reasons that make sense.
The final drive……tire size will determine final drive to ground. Period. Call it revs per mile or what ever else it is a final drive to ground. From a stock standpoint doesn’t mean shit, start exercising credit cards on tire bling it does. Slap a wheel barrow tire on a Willys with 3.73s and presto you have diff ratio of 23.3:1(random ass number), same truck slap 37s and suddenly it’s a diff ratio of 3.44:1( random ass number). This is extremely over simplified but it captures what any of us whom have lifted bits and bots that regears usually follow bigger tires but ultimately any tire can be mated to a 3.73.

 

[DrewsJT]

My Overland has the 255/70R18 with the 3.73 gearing. It's what the factory gave me.

Mine too

 

[Free2roam]

Rubicon Gas comes standard with 285x70Rx17C 's when it comes to the models with the 3.73 gearing . I think tire size changes depending on what model you buy. As stated Rubi ,Mojave,Maxtow have 4.10 gears. As standard option.
I am not familiar with what is in the diesels as to axle ratios or tire sizes.

All diesels have 3.73 as far as I'm aware. Doesn't matter which trim or model.

 

[MudderNuker]

So which gladiator factory size tire actually has the 3.73 gear ratio, the 245/75/17 the 255/75/17 or the 285/70/17 being they offer 3 different size tires I'm guessing the 3.73 is based of the smaller diameter tire, the 245/75/17

All tires with the exception of the 285/70's that come with 4.10s on Ruby's and Mojave and the Ruby diesel with its 3.73.

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