3.0L Eco Diesel and 35s

BuffaloBill

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I’m in the minority, having regeared for 35s.

I agree the stock 3.73 was not bad with the 35s (actually mine are 315/70/17 K02). The Ecodiesel and awesome transmission combination never failed to get the job done. But it did, understandably, run 7th gear more often than with the stock 33s, at 2-lane road speeds of 55-60mph, depending on slope and/or headwind. That’s what the transmission‘s for, right?

Well, during this past winter I ran the stock 33s. That spoiled me, for the more pleasurable shifting behavior and how more load could be applied (wind or slope) without initiating a downshift. I had driven it stock very little, before putting on the 315/70/17s.

I enjoy wrenching on my own stuff but hadn’t done a gear swap before. So it was something I wanted to experience. I bought a used set of 4.10s (and one new set also…), spent many hours on the install, but came out the other side with a Jeep that feels more like mine now.

It’s now geared effectively, a few percent deeper than stock, and is so to my liking. My mpg has been creeping up it seems, as it accumulates miles (currently have just under 9K miles on it). Traveling 60mph roads and local small towns, I average 26.5-27mpg (evic) when it’s not too windy. So can’t really tell if I lost any mpg.

I would not have paid a shop to do this, as the 3.73 wasn’t bad. But I do prefer the 4.10s.
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guarnibl

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Yeah, the thread is about running 35s so I made an assumption.

I also wish you could get 4.10s with the diesel. Maybe not necessary for 35s but 37s would benefit for sure.
Agreed. And it seems they offer axle ratio options for trucks — bummer they don’t for the Wrangler unless you get the new XR package for $4k.
 

houseofdiesel

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Weight is a secondary consideration. The bigger impact is the change in the tire diameter. Going from 33's to 35's roughly cuts around 6% of the effective power from the engine to the ground. Adding a few dozen pounds of tire is well under 1% extra weight. Even as additional rotational mass, that impact is clearly secondary.

Weight does play a minor role though. If you regear for larger diameter tires, you should always round up your gear choice to compensate for the additional weight, as well as the increased rolling resistance of a larger contact patch of the wider tire. But weight is not why you regear.

The thing about the 3.0 diesel is that it makes tons of power where it counts (low end torque). So the 6% loss in effective power due to the larger diameter tires just cuts into the ample margin of extra power that the engine produces over the 4 and 6 cylinder gas engines.
6%? On a 500 rwhp comp truck I'd only lose 5 hp per inch. That's 2% not 6%. Maybe on a gasser someone will lose 6% but not on a diesel.
 

AppleJacks23

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Bfg ko2s 315/70/17 on a stock jlurd for over 10k miles now and would never go back to 33s! Will update when my Clayton lift arrives late this month..

DSC_0289.JPG
 

SolarWizard

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What’s the purpose of lighting up the wheel wells?
 

SilverBug86

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BFG 35’s no lift. AEV wheels with slightly more offset. No problems.
Please don’t use wheel spacers!

4754D201-F7B3-4A5F-9DC1-D204B9A46DDD.jpeg
What is the minimum offset to clear any rubbing? I may just buy new wheels. Definitely not going to put spacers on the steers.
 

NCJL

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What is the minimum offset to clear any rubbing? I may just buy new wheels. Definitely not going to put spacers on the steers.
The AEV wheels have about 5.75 offset. Verify on their website. I also have aftermarket fenders.

image.jpg
 

SilverBug86

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Bfg ko2s 315/70/17 on a stock jlurd for over 10k miles now and would never go back to 33s! Will update when my Clayton lift arrives late this month..

DSC_0289.JPG
I have the EcoDiesel Rubicon on the way. I understand that it sits a little higher than the rest.
Do the 35" KO2s rub with low psi? Say 20psi? Full flex, steer locked in either direction? I don't really want new wheels or lift, while under the 3 year warranty. Been searching all throughout the forum to find this answer.
 
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CWRUYOTE

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I have the EcoDiesel Rubicon on the way. I understand that it sits a little higher than the rest.
Does the KO2s rub with low psi? Say 20psi? Full flex, steer locked in either direction? I don't really want new wheels or lift, while under the 3 year warranty. Been searching all throughout the forum to find this answer.
I ran my stock JLURD at Uwharrie last weekend and had no problems with the stock 33" BFG KO2s at 15 PSI. My only problem was being a little too low and scraping my pumpkins and crossmember occasionally.

I hope to solve that slight problem with a lift and more armor underneath.

Pic for attention ;)

IMG_0793.jpeg
 

SilverBug86

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Should have clarified, 35", not stock.
 
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