What gear ratio should I install in my Jeep Wrangler TJ / LJ? (and other re-gearing FAQs)

If you don't want gears that are made overseas (Revolution) using import metals go with Dana original equipment. Dana builds their gears in the USA using domestic metals and is the genuine gear sets for our Dana axles.

Dana builds the Dana 30, Dana 35, and the Dana 44 that our TJ’s/LJ’s come from the factory with.

Dana offers an aftermarket site that carries gears and other Dana axle products. Not sure how much Dana supports the 30 and 35. But it does support the 44. Im shopping for 44 gears currently.

https://www.danaaftermarket.com/part/id/435476?pn=22105-5X&cp=0
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Pacoson71 said:
With the 42rle the final gear ratio on 5.38 Gears is 3.71..... taken from Grim Reaper spreadsheet with 33in tires
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With 3.73s and the 6speed.. for guys who can shift.. the final is 3.13.

taken from Grim Reaper spreadsheet with 33in tires

altho tire size has zero influence on the ratios.
 
reddvltj said:
Here's a link that gives some good information, maybe it will help people decide what gearing they want related to how they want to use their Jeep.

https://www.quadratec.com/c/reference/gear-ratio-guide-for-larger-tires
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Great chart, completely accurate. I had 33s, 3.07s in a YJ and I got 25mpg at 65mph turning 2100rpm in 4th as the chart shows. No doubt 3.25s, 3.55s would have let me use 5th gear on the highway but in 4LO.... I could hit 60mph in 5th, 3.07s, 33s.

Very driveable on forestry roads. It ran like a Mustang. I prefer the Mustang feeling to the tractor feeling crawling up a waterfall.
 
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L J said:
No offense intended but that generic chart is terrible. Use the gear ratio calculator at http://www.grimmjeeper.com/gears.html.






:unsure:


:ROFLMAO:
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No offence taken... As for it being terrible, that is all point of view. For someone who has gone way beyond stock with their drive train then yes it is a bit simplified, but for someone just starting out that has not done anything besides lift and tires I'd say it is plenty helpful... Not everyone is a hard core wheeler.... 😱🤪
 
The problem with that Quadratec chart is that it is so generic. It simply takes a 1:1 value and gives a gear ratio. It does not account for engine size, transmission gearing, final drive, vehicle size etc. I would argue that it is actually worse for new/uneducated wheelers.
 
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Rob5589 said:
The problem with that Quadratec chart is that it is so generic. It simply takes a 1:1 value and gives a gear ratio. It does not account for engine size, transmission gearing, final drive, vehicle size etc. I would argue that it is actually worse for new/uneducated wheelers.
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I think we'll have to agree to disagree with the information being worse for "new/uneducated wheelers". While having all the knowledge provided by grimmjeeper would be a benefit, it does not make Quadratec's chart a detriment. Grimmjeeper's chart is great for telling people what they get with specified gear ratios combined with under/overdrive boxes, t-case gearing, and trans gear ratios for every gear, it can easily be overwhelming for people that simply want to get their rpm range back as close as possible to what it was with stock tires once they've put on larger tires, and that is exactly what Quadratec's chart does.
 
mrblaine said:
Why do so many dismiss good knowledge as something only hardcore wheelers need? Hardcore or not, knowing the ins and outs of how to figure stuff out is certainly better than the alternative.
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Ok so maybe that statement was not the best choice of words, in no way was meaning to say that only hard core wheelers can benefit from Grimmjeeper's chart. It is full of great information for those people that are looking for those stats. I simply meant not everyone wants or needs that level of information.
 
reddvltj said:
... that simply want to get their rpm range back as close as possible to what it was with stock tires once they've put on larger tires ...
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over-drive ... the Qtec chart doesn't take it into account.
 
L J said:
over-drive ... the Qtec chart doesn't take it into account.
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You are correct... it doesn't, and yes overdrive ratios are not all the same. You and a few others seem to have taken offense, in one form or another, that I posted a chart that you deem inadequate. Again I know it is not as In depth as Grimmjeeper's chart, NEVER said it was. It even says above the chart "This chart is based on 65 MPH and a gear ratio of 1:1, on a manual transmission in 4th gear. Please NOTE: If you have an automatic transmission your RPM will higher due to slippage in the transmission and the torque converter. With an overdrive transmission your RPM in overdrive will be 15% to 30% less than indicated."
 
reddvltj said:
You are correct... it doesn't, and yes overdrive ratios are not all the same. You and a few others seem to have taken offense, in one form or another, that I posted a chart that you deem inadequate. Again I know it is not as In depth as Grimmjeeper's chart, NEVER said it was. It even says above the chart "This chart is based on 65 MPH and a gear ratio of 1:1, on a manual transmission in 4th gear. Please NOTE: If you have an automatic transmission your RPM will higher due to slippage in the transmission and the torque converter. With an overdrive transmission your RPM in overdrive will be 15% to 30% less than indicated."
Click to expand...

You are forgetting that the chart makes recommendations along with just giving RPM. The "optimal gear ratio" that the chart gives is misleading because it doesn't take into account a lot of relevant variables. If I was new to Jeeps, I'd look at that chart and think that 4.56 is recommended for my new 35 inch tires when that isn't the case for a lot of Jeeps.
 
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I gave examples of why the QT chart is a poor guideline. It is a "math" chart that only takes into account tire size and mph. It doesn't make adjustments for gas vs diesel, 4 cyl vs V8, 3 spd auto vs 6 spd manual, etc, etc. It is simply a one size fits all, which doesn't work.
 
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reddvltj said:
You and a few others seem to have taken offense, in one form or another ...
Click to expand...

puts on kid gloves ... We merely offered that the Q-tec chart isn't the best reference and I suggested another. 😉
 
jodomcfrodo said:
You are forgetting that the chart makes recommendations along with just giving RPM. The "optimal gear ratio" that the chart gives is misleading because it doesn't take into account a lot of relevant variables. If I was new to Jeeps, I'd look at that chart and think that 4.56 is recommended for my new 35 inch tires when that isn't the case for a lot of Jeeps.
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It does say that.... but it also shows they would be at the bottom side of the "optimal" ratios... leaning toward fuel economy... it also shows 4.88 on the upper side of that range.... To me that's where it leaves the decision up to you the owner of the vehicle to determine if you want more power and better crawl ratio or lower RPMs on the highway.
 
L J said:
puts on kid gloves ... We merely offered that the Q-tec chart isn't the best reference and I suggested another. 😉
Click to expand...
No kid gloves needed, you're right Qt's chart is a complete generalization... I concede that... I'm not trying to change anyone's mind as to that fact. Grimm's chart is way more in depth... that's a given. I didn't know Grimm's chart existed when I found the Qt chart.
 
Gear ratio selection usually brings out much debate, which is a good thing. I agree with what was said in a previous post. First step. Figuring out exactly the type of wheeling your really going to be doing and how your going to be driving the rest of the time. I see lower end ratios being recommended which may be better suited for hardcore off-road use but not optimum for a daily driver. The Quadratec chart is a good generic starting point and is geared more towards people that will mostly be driving on the road and maybe some light wheeling. It will get you back in range of what stock gearing was from the factory. The hardcore off-road people will definitely want to be geared lower than what the Quadratec chart lists. My 05 4-cly 6-spd came with 3.73 gears. For a daily driver running 33’s and 4.56 gears with some moderate off-roading. It’s fine on the road. Easily pulls 6th gear, off the line, hills etc. I’ve used this combination before and it did well on moderately difficult wheeling. 4.88’s would be good for the 4-cly on 33’s that will be more trail oriented, but is still mostly a daily driver. 5.13’s definitely more off-road oriented. There is no definitive one size fits all ratio. General statement here. Take Quadratec’s chart and shift it to the right one row and it will be a decent starting point for the majority of people that don’t wheel hard.
 
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