35's vs 37's??

Smess · Jun 19, 2021

So well all know now that the 392 can accomodate a 35 or 37 with no change other than to the spare tire carrier for the 37 and an upgrade to the 35 if you didnt get the factory option.

Historically a 3.73 and a 35 run perfect together all around and a 4.10 was the option people got when they knew they we going bigger.

I am on the fence as I have run both and obviously the 37's look perfect but I also noticed the 392 tends to drop in to 4cyl mode which helps fuel economy quite a bit. I am an around town driver and it is hard to measure fuel economy when not on highway as there are so many variables around town stop and go.

I did do an instant economy at 60mph on both but since that instant fluctuates much every seconds it is really hard to make a determination but I will say that I notice the difference was null but that 4cyl light is what is making me wonder.

On other forums I have read that guys are noticing the same thing and we all know that taller tire takes less revolutions so is there any way possible a 37 could use no more fuel?

I think the 3.73's might be borderline with 37's but with all the power maybe pushing on the gas pedal might solve that. Most people dont like the wrong gearing because of all the upshifting and downshifting on the highway but thats when the motors power is borderline.

37's average weight is high 70's to low eights. Stock tire in the 50's and 35 I would imagine in the middle.

I know this is a crazy question because the 392 is no new who has had a chance to do the testing or wants to spend the money but you never know.

Anyone know? Heard?

Left pic 35's on AEV Borah Wheel, right pic 37x13.5 also on AEV Borah

Jeepn4x4 · Jun 29, 2021

Smess said:
So well all know now that the 392 can accomodate a 35 or 37 with no change other than to the spare tire carrier for the 37 and an upgrade to the 35 if you didnt get the factory option.

Historically a 3.73 and a 35 run perfect together all around and a 4.10 was the option people got when they knew they we going bigger.

I am on the fence as I have run both and obviously the 37's look perfect but I also noticed the 392 tends to drop in to 4cyl mode which helps fuel economy quite a bit. I am an around town driver and it is hard to measure fuel economy when not on highway as there are so many variables around town stop and go.

I did do an instant economy at 60mph on both but since that instant fluctuates much every seconds it is really hard to make a determination but I will say that I notice the difference was null but that 4cyl light is what is making me wonder.

On other forums I have read that guys are noticing the same thing and we all know that taller tire takes less revolutions so is there any way possible a 37 could use no more fuel?

I think the 3.73's might be borderline with 37's but with all the power maybe pushing on the gas pedal might solve that. Most people dont like the wrong gearing because of all the upshifting and downshifting on the highway but thats when the motors power is borderline.

37's average weight is high 70's to low eights. Stock tire in the 50's and 35 I would imagine in the middle.

I know this is a crazy question because the 392 is no new who has had a chance to do the testing or wants to spend the money but you never know.

Anyone know? Heard?

Left pic 35's on AEV Borah Wheel, right pic 37x13.5 also on AEV Borah

Can you post photos of the 37s front and back shots im curious how far the stick out. also what size wheels are you running, do you know the offset? thank you looks awesome with 37s

Smess · Jun 30, 2021

Jeepn4x4 said:
Can you post photos of the 37s front and back shots im curious how far the stick out. also what size wheels are you running, do you know the offset? thank you looks awesome with 37s

Sorry had an iPhone iCloud photo meltdown and lost most pics. Wheels are AEV Borah's which are pretty conservative compared to most AEV wheels. Unlike other wheel manufacturers that have "one size fits all" AEV makes the Borah for the JK and JL/JT with different specs so they dont stick out beyond the wheel wells like most other wheels do and they took in to consideration that there are two different width axles on the new Jeeps. Therefore all previous backspacing and offset numbers are out the window. Thats why I run AEV products and if I buy others I base my decision off what specs AEV is using, because they do the R&D that other companies dont do and AEV is the reason why the Gladiator and 392 are in our garages today.

AEV has been doing Hemi conversions (since 2004-5 on TJ's) and installing 6.4's since 2011 and the AEV Double Cab Brutes popularity is what made Jeep decide to build the Gladiator. They were the only company in the history of America to be able to take a vehicle off the assembly line, put a lift, Hemi, and other mods and then put it on the Franchise dealers lot and get 3/36 warranty, financing, and insurance. As a result the Gladiator and 392 were built and now AEV is not allowed to build certain things because they were paid for their R&D.

The wheel is 17x8.5, Offset is +25 and backspace is 5.72"

American Expedition Vehicles - AEV Off Road Parts Store

Visit American Expedition Vehicles (AEV), the leading store for high-quality off-road vehicle parts. Discover the essential products for your next adventure.

www.aev-conversions.com

Pictured below is a Double Cab Brute which was last produced in 2018 and a 2017 6.4 JK Wrangler.

If you are not familiar with AEV and you have a 392, you should be. Check it out

They also make the Ram Prospector, Colorado Bison, and a smaller modded Ran Rebel.

AEV badged products have a pedigree, they are stamped with a year and production number. Until the 392 showed up a used Jeep with AEV lift and wheels and bumpers would bring higher re-sale value than Jeeps with other after market products because unlike other manufacturers of after market products theirs are tested and meet US safety standards or they would not be allowed to do conversions and then sell the vehicles as new with warranty.

The vehicles shown below were quick photos I grabbed, most AEV vehicles are much nicer. Those two are not the best examples of what they produce. I have owned them since 2008 but between the Diesel and the 8 speed paired with the 6cyl and now the 392 there is little demand for a Jeep brand new and then torn apart and a Hemi added for 20k up.

Asuperheat · Jun 30, 2021

I don't think you can compare the 392 with other motors in the lineup. It has massive TQ. Closest thing would be the diesel when it comes to the gearing/Tire size but it has more TQ available at any given RPM than the diesel looking at Livernoris post of the dyno run. I expect it will be fine with 37's but you will will loose MPG's. That's just physics. Larger heavier wheel takes more power to move, more power = more fuel. gearing gives you some More Tq to the wheel but there is other variables to consider on the exact match up when comparing MPG.

Smess · Jun 30, 2021

I noticed for the short period of time that I was running the 37's the 4cly light seemed to come on a lot more often which means I am saving fuel.

Doesn't matter now, I put on the pedal commander now and am now averaging 7-8mpg down from 12 but it sounds so good and is so much more fun to drive I dont care about the fuel. Jeep left a lot on the table and the Pedal Commander brings it back to the table.

rbarton · Jun 30, 2021

Asuperheat said:
I don't think you can compare the 392 with other motors in the lineup. It has massive TQ. Closest thing would be the diesel when it comes to the gearing/Tire size but it has more TQ available at any given RPM than the diesel looking at Livernoris post of the dyno run. I expect it will be fine with 37's but you will will loose MPG's. That's just physics. Larger heavier wheel takes more power to move, more power = more fuel. gearing gives you some More Tq to the wheel but there is other variables to consider on the exact match up when comparing MPG.

I went with 35's on mine. I didn't want to lose the torque to the pavement with going all the way to 37's. I also think even though the 392 is higher than a regular rubicon, it could stand another inch or two with 37's. So I decided to wait for lifts appropriate for the 392 and do 35's for now.

I am happy with the 35's but there was some loss of acceleration. Ride quality is still really good. And the existing tire carrier works with it. In fact the 35 kind of rests on the stock bumper so the tire weight is partially supported by the bumper. So there are no rattles due to the tire. That was an unexpected bonus.

Jjirish · Jul 25, 2021

rbarton said:
I went with 35's on mine. I didn't want to lose the torque to the pavement with going all the way to 37's. I also think even though the 392 is higher than a regular rubicon, it could stand another inch or two with 37's. So I decided to wait for lifts appropriate for the 392 and do 35's for now.

I am happy with the 35's but there was some loss of acceleration. Ride quality is still really good. And the existing tire carrier works with it. In fact the 35 kind of rests on the stock bumper so the tire weight is partially supported by the bumper. So there are no rattles due to the tire. That was an unexpected bonus.

So my 35s and dirty life wheels are being put on this week….. please expand on your loss of acceleration.

Jjirish · Jul 25, 2021

Smess said:
I noticed for the short period of time that I was running the 37's the 4cly light seemed to come on a lot more often which means I am saving fuel.

Doesn't matter now, I put on the pedal commander now and am now averaging 7-8mpg down from 12 but it sounds so good and is so much more fun to drive I dont care about the fuel. Jeep left a lot on the table and the Pedal Commander brings it back to the table.

Ok. Pedal commander. Tell me everything.

Smess · Jul 28, 2021

Jjirish said:
Ok. Pedal commander. Tell me everything.

Pedal Commander says they take the lag out of the sky by wire. In other words the pedal has some slop in it (applies to all fly by wire vehicles of which almost all cars are today) so a little old lady that touches her gas pedal does not drive through the garage door accidentally because the pedal is too sensitive.

I call bs, yes the pedal commander does take out the slop but it sure does act like a tune in every vehicle I put it in. It is very effective in turbo diesels but what it did to the 392 was unreal.

If you want to pass you normally push on the pedal and the vehicle downshifts and accelerates. When you have the PC you barely have to push on the pedal depending on how you have it set.

I have installed one in my Diesel Gladiator and 392 and I would not waste the money on a chip or tune or any claim to increase hp or performance. Its hard to explain words but just try it, I have yet to meet anyone that I have installed one in their vehicle and they were anything but thrilled.

on the 392 I would not give it all it has, I think you should not go over Sport 0 setting which will make sense to you when you get it. Otherwise I think you might leave the front axle and transfer case sitting on the ground at the stop light you just left.

I would recommend if you like hp and can handle it, get the tazer mini and force the 2wd only mode and then you can get aggressive with the PC. If not then stick to that Sport 0 which is like 50% of what it has to offer.

The sound alone of the engine compared to stock is worth the money.

Like the old Life Cereal commercial "try it you will like it"

Two friends that have driven my 392 with the PC and Tazer and the PC turned up to max both said that the 392 was one of the most retarded things they have ever driven.

Be careful its a handful if you have larger tires etc, you are up there and now you have a lot of hp up there.

the PC with 35's is great, the PC with 37's is needed and I hate to say it but probably time for a re-gear with 37's to get the best response and fuel economy.

Jjirish · Jul 28, 2021

Smess said:
Pedal Commander says they take the lag out of the sky by wire. In other words the pedal has some slop in it (applies to all fly by wire vehicles of which almost all cars are today) so a little old lady that touches her gas pedal does not drive through the garage door accidentally because the pedal is too sensitive.

I call bs, yes the pedal commander does take out the slop but it sure does act like a tune in every vehicle I put it in. It is very effective in turbo diesels but what it did to the 392 was unreal.

If you want to pass you normally push on the pedal and the vehicle downshifts and accelerates. When you have the PC you barely have to push on the pedal depending on how you have it set.

I have installed one in my Diesel Gladiator and 392 and I would not waste the money on a chip or tune or any claim to increase hp or performance. Its hard to explain words but just try it, I have yet to meet anyone that I have installed one in their vehicle and they were anything but thrilled.

on the 392 I would not give it all it has, I think you should not go over Sport 0 setting which will make sense to you when you get it. Otherwise I think you might leave the front axle and transfer case sitting on the ground at the stop light you just left.

I would recommend if you like hp and can handle it, get the tazer mini and force the 2wd only mode and then you can get aggressive with the PC. If not then stick to that Sport 0 which is like 50% of what it has to offer.

The sound alone of the engine compared to stock is worth the money.

Like the old Life Cereal commercial "try it you will like it"

Two friends that have driven my 392 with the PC and Tazer and the PC turned up to max both said that the 392 was one of the most retarded things they have ever driven.

Be careful its a handful if you have larger tires etc, you are up there and now you have a lot of hp up there.

the PC with 35's is great, the PC with 37's is needed and I hate to say it but probably time for a re-gear with 37's to get the best response and fuel economy.

Very perfect reply!! Thank you!

392Stinger · Jul 28, 2021

Just added 35” to mine today… Went with Wicked off road wheels and Goodyear Ultra terrain tires from DT.
Really like to stance now and 35”’s are perfect for my needs.

YukonCornelius · Jul 28, 2021

Smess said:
Pedal Commander says they take the lag out of the sky by wire. In other words the pedal has some slop in it (applies to all fly by wire vehicles of which almost all cars are today) so a little old lady that touches her gas pedal does not drive through the garage door accidentally because the pedal is too sensitive.

They actually increase the voltage to the TB relative to your foot position. Here’s probably the best explanation and VISUAL demonstration of how they work out there:

(also laughed at the little old lady and garage door remark

)

ScrappyCoco · Jul 28, 2021

YukonCornelius said:
They actually increase the voltage to the TB relative to your foot position. Here’s probably the best explanation and VISUAL demonstration of how they work out there:

(also laughed at the little old lady and garage door remark )

Very true. Had a 99mm Fastman TB in the HC and had to be opened to 102mm. I would definitely upgrade the TB with the PC.

ScrappyCoco · Jul 28, 2021

5.7L 6.1L 6.4L Hemi V8 Throttle Bodies - The Fastman

DOTCOM · Jul 28, 2021

Wait…

We can fit 37x13.5’s without any additional mods?

DOTCOM · Jul 29, 2021

I really want to fit 37x13.5’s but all the local shops are saying it’s not possible with the stock 392 lift.

has someone here done it without any problems?

ScrappyCoco · Jul 29, 2021

DOTCOM said:
I really want to fit 37x13.5’s but all the local shops are saying it’s not possible with the stock 392 lift.

has someone here done it without any problems?

BenLandry · Jul 29, 2021

DOTCOM said:
I really want to fit 37x13.5’s but all the local shops are saying it’s not possible with the stock 392 lift.

has someone here done it without any problems?

I did it, only rubbing is on big dips in the road with other people or weight in my Jeep. The rubbing is on the back inner fender, towards the back of it. I’d already planned a fender chop job, just waiting on brackets.

DOTCOM · Jul 29, 2021

BenLandry said:
I did it, only rubbing is on big dips in the road with other people or weight in my Jeep. The rubbing is on the back inner fender, towards the back of it. I’d already planned a fender chop job, just waiting on brackets.

Thank you for chiming in!

If I go with the 13.5's - do I need to do anything with changing the gears / timing / adding a stabilization bar to prevent the death wobble on the highway?

BenLandry · Jul 29, 2021

DOTCOM said:
Thank you for chiming in!

If I go with the 13.5's - do I need to do anything with changing the gears / timing / adding a stabilization bar to prevent the death wobble on the highway?

I put a fox stabilizer. These are on 20x10 -18 offset, fuel rebel wheels, lots of weight. I have a pedal commander also, I’m sure it slowed down some but not much, it’s scary fun to drive. I’m sure flexed it would rub here or there but I’m not a rock crawler, mud and sand and malls for me but I drive it like a race car. I’m pricing 4:56 gears just to make the universe right but not because it’s a significant power loss. If you run a spare you’ll need a relocation bracket, i went with Teraflex which came with a third brake light relocation bracket also. You also need something to correct the speedometer, if not you will be way off and even your mileage will be not measuring correctly. I have a JL Tazer, it will also allow you recalibrate for gears of you choose to do so down the line…it has a few more secrets also. Lots of guys are running it on this forum.