Do I need to Regear?

rubi_vette

rubi_vette

Member
It is time for me to get new tires... Local Jeep dealership is running a special (starting March 1st) for Buy 3 get 1 free. So... me being curious, currently on a 3.5" lift with 35s; a Rubicon JLU (4:10 gearing). Ultimately, for street driving... Do I need to regear? I would like to fill the gap a little bit using 37s, but do not want to spend money on regearing.

I've been reading forums and watching videos, some say yes, and others say no. Overall, it is not a deal breaker if I DON'T go to 37s, just while I'm here going to order new tires, I'm trying to see if it's worth it.

I find 35s on the stock gearing is more than enough, so it is my winter daily but not my summer. Now the question really is, do I need to regear moving to 37s? Or will everything be fine? Figured I'd ask a reliable resource place such as this one.
 
You can technically get away with 4.10’s on 37’s BUT you will be hard pressed to hit 8th gear. So other than that, yes you can. Of course going to a ratio of 4.88’s would be ideal for daily driving and 37’s or 5.13’s if you want that little extra. Also worth noting that with proper gearing, your shift points will be much better and of course getting 8th gear back. Hope this helps.
 
Disciple Off Road said:
You can technically get away with 4.10’s on 37’s BUT you will be hard pressed to hit 8th gear. So other than that, yes you can. Of course going to a ratio of 4.88’s would be ideal for daily driving and 37’s or 5.13’s if you want that little extra. Also worth noting that with proper gearing, your shift points will be much better and of course getting 8th gear back. Hope this helps.
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Couldn’t have said it better myself 👍🏻
 
Disciple Off Road said:
You can technically get away with 4.10’s on 37’s BUT you will be hard pressed to hit 8th gear. So other than that, yes you can. Of course going to a ratio of 4.88’s would be ideal for daily driving and 37’s or 5.13’s if you want that little extra. Also worth noting that with proper gearing, your shift points will be much better and of course getting 8th gear back. Hope this helps.
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It seems like I'll stick with 35s! I don't want to get too complicated. Just figured I'd look and double-check before ordering on Wednesday! I will say, even 35s are huge! I'm used to the traditional 33's in my other ride. Lol! Thank you for the advice!
 
Since this thread is not to old - I will revive it. I just got back in to the jeep game with a Rubicon EcoDiesel. I ran 37s on my 2013 JK - which I think also had the 3.73 gears like the EcoDiesel if I am not mistaken. I seems although not great, it wasn't that horrible on the JK.

It seems the EcoDiesel with the added torque is fine to run 37s from what I have researched so far. I have a 3.5 Long arm with 37" Mickey Thompson Bajas on order.
 
silversmoke said:
Since this thread is not to old - I will revive it. I just got back in to the jeep game with a Rubicon EcoDiesel. I ran 37s on my 2013 JK - which I think also had the 3.73 gears like the EcoDiesel if I am not mistaken. I seems although not great, it wasn't that horrible on the JK.

It seems the EcoDiesel with the added torque is fine to run 37s from what I have researched so far. I have a 3.5 Long arm with 37" Mickey Thompson Bajas on order.
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Does the Jeep utilize all the gears and hold 8th at highway speeds?

My 3.6 ran fine with the stock Rubicon 4.10 gears but I rarely saw it shift into 8th, regeared to 4.88 and can now set the cruise control at 75 and run in 8th gear.

IMO since the diesel has much more torque, 4.56 would be the ratio I'd run with 37s
 
jeeeep said:
Does the Jeep utilize all the gears and hold 8th at highway speeds?

My 3.6 ran fine with the stock Rubicon 4.10 gears but I rarely saw it shift into 8th, regeared to 4.88 and can now set the cruise control at 75 and run in 8th gear.

IMO since the diesel has much more torque, 4.56 would be the ratio I'd run with 37s
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Same…. Another impact on gearing is weight if you’ve added a ton of heavy parts and carry tools and gear all the time gearing will really pay off
 
jeeeep said:
Does the Jeep utilize all the gears and hold 8th at highway speeds?

My 3.6 ran fine with the stock Rubicon 4.10 gears but I rarely saw it shift into 8th, regeared to 4.88 and can now set the cruise control at 75 and run in 8th gear.

IMO since the diesel has much more torque, 4.56 would be the ratio I'd run with 37s
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I have zero issue running 8th gear with the diesel. There is no reason to gear the diesel unless you’re going to 40s. I’m not sure many people appreciate how powerful the 3.0 is.
 
onlyone said:
I have zero issue running 8th gear with the diesel. There is no reason to gear the diesel unless you’re going to 40s. I’m not sure many people appreciate how powerful the 3.0 is.
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On my 2013 with the 3.6 Pentastar I went to 5.13 gears. That really helped on that engine. I am with you...with over 400 ft lbs of torque I will be surprised if it needs a regear once the computer knows the tire change.

I have owned many diesel HD trucks and currently own a 2022 Powerstroke DUally, so once I found a Rubi with the EcoDiesel I bought it before they go away. I will never own a gas truck again, I am sure if people owned a EcoDiesel they would feel the same way about owning a gas or diesel Jeep. A test drive cant really appreciate the Diesel.

The videos' I have seen so far indicate that the EcoDiesel really doesn't see any change going to 37s.
 
silversmoke said:
On my 2013 with the 3.6 Pentastar I went to 5.13 gears. That really helped on that engine. I am with you...with over 400 ft lbs of torque I will be surprised if it needs a regear once the computer knows the tire change.

I have owned many diesel HD trucks and currently own a 2022 Powerstroke DUally, so once I found a Rubi with the EcoDiesel I bought it before they go away. I will never own a gas truck again, I am sure if people owned a EcoDiesel they would feel the same way about owning a gas or diesel Jeep. A test drive cant really appreciate the Diesel.

The videos' I have seen so far indicate that the EcoDiesel really doesn't see any change going to 37s.
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I agree. I have had a gladiator and my current wrangler with 37s and the power of them still put a smile on my face. I can easily roast those tires with little effort. I still average 25 or better with 37s every fill up. My brother has a diesel gladiator on 37s and just installed the banks kit. He says it’s just nuts how much power it has now.
 
onlyone said:
I agree. I have had a gladiator and my current wrangler with 37s and the power of them still put a smile on my face. I can easily roast those tires with little effort. I still average 25 or better with 37s every fill up. My brother has a diesel gladiator on 37s and just installed the banks kit. He says it’s just nuts how much power it has now.
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My wife has a 2023 Chrysler 300 and has about an hour drive to work everyday - she has been getting around 27MPG driving 75-80 mph.

She had to use the Jeep last week when hers was at the dealer for couple days. She was getting around 25MPG...will be interesting to see how the lift and tires affect that.
 
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