‘21 JT Rubi—Regear to handle 37s?

[trappjp]

Just bought my 2021 Gladiator Rubicon and am considering running 37s but have heard conflicting reports on whether or not to regear. I know I can run 37s on the Rubi, but will it suffer on highway…ex: fails to get to 8th gear? What experiences do you have with JT Rubi on 37s?

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[USMC-SSGT]

Non diesel? It’ll suck on 37s and 4.10. You likely won’t notice a whole lot empty driving around town however. Hit the highway and you’ll mostly live in 6th gear and the occasional 7th. 8th only downhill. If the grade goes up even a few percent it’ll downshift to 5th. Towing, even worse.

The good news, at least it’s not 3.73. If they are super light and undersized like a 37” BFG on a light wheel you may be able to get away with it.

 

[trappjp]

Non diesel? It’ll suck on 37s and 4.10. You likely won’t notice a whole lot empty driving around town however. Hit the highway and you’ll mostly live in 6th gear and the occasional 7th. 8th only downhill. If the grade goes up even a few percent it’ll downshift to 5th. Towing, even worse.

The good news, at least it’s not 3.73. If they are super light and undersized like a 37” BFG on a light wheel you may be able to get away with it.

Thanks!

 

[Deleted member 22728]

Gear ratio matched to powertrain type and tire size. 4.88 for gas and 4.56 for diesel or HEMI with 37" tires, for example, allow the gear ranges to once-again perform per original designs; you basically get full functionality and shift freedom back. The difference felt is immediate, shift strategies return to OE spec., including intuitive upshift and downshifting.

 

[trappjp]

Great info, thanks all. My takeaway is, just because you can do something doesn’t mean you should. I don’t want to run 37s and lose performance so I am going to stick with my plan to add 35s this coming week and will consider 37s and regearing in the future.

 

[trappjp]

Installed the 35s today. I have wheels on order but given supply chain likely won’t see them before the end of January. These Nitto Ridge Grapplers are significantly more quiet than the stock 33” Falken M/Ts

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