40's on 392?

[richk225]

This was a 6-figure build I did a bunch of things to clear the 40’s… but only mentioned what was cut away. For the front shocks, I changed my spring rates, added AGM sliders, notched the frame and moved the lower shock mounts. I also needed to replace a few boots and install an HD Antirock in the front… but I tacked those at home.

It's A shame that a 392 delivered with tax is already a 6 figure build

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[richk225]

Well it’s a really good thing that I’ve never encountered one, which was really my point!

Mall crawlers stay on the pavement and, when they do go off-road, they avoid the hard trails. This doesn’t make them ‘less-than’ anyone else out here just because they’re too scared/smart to scratch up their 100k+ jeep.

Maybe they are smart enough not to get in over their heads?

 

[richk225]

He’s a flat-lander that retired doesn’t make him an authority on anything. He’s a guy that that simply gets his kicks by showing everyone how special he thinks he is by putting down the people with better toys and a lot more money than he has. I’ve also noticed that he is followed by a small group of guys that are dumb enough to believe him… likely because they want to be him.

But what do I know… but I bet my education, pay check, and Jeeps are bigger than yours, combined

Just another flatlander who doesn't throw a bunch of negative crap back at you

I often lead group ride of 30 to 40 Jeeps and have lead a 60 or so Jeep ride. I have also been an instructor for Overland Expo. I teach how to plan multiple month off roading adventures and how to use mapping software like Gaia, Google maps, Onx. How to find dispersed camping and so on.

I had applied to be an instructor at Overland Expo West this year, but because of my father in laws death, I cancelled out. Sadly.

So not trolling, we just wheel a lot with a lot of Jeep people from all over. We have seen a thing or two

 

[Mudduck]

Maybe they are smart enough not to get in over their heads?

@richk225 Ya know man, some fathers raise amazing men that become amazing fathers… And some apparently just beat off into a flower pot and raise blooming idiots… That is what we have all witnessed here in this thread, thanks to Phillip.

 

[richk225]

@richk225 Ya know man, some fathers raise amazing men that become amazing fathers… And some apparently just beat off into a flower pot and raise blooming idiots… That is what we have all witnessed here in this thread, thanks to Phillip.

Well said!!

 

[SSWIM]

Wow just WOW. This thread went to pooooo in record time.

Sam

 

[Tank2112]

Just keep in mind that if you go to 40” tires on 392 Wrangler, you will seriously change the on-road drivability. I don’t care what anyone says. I’ve been off-roading Jeeps for 20 years. Been down the road of trying to build on on-road Jeep that can run buggy trails.
Can’t have both.
The weightrotating mass and stiffer side wall of tires will dramatically affect the power and ride quality. Steering parts, knuckles, ect…will wear much quicker. It will vibrate after a few thousand miles if not right away.
If you off-road very difficult trails you risk breaking ring/pinion gears, drive-shafts. Questionable how long clutches in factory transfer case will hold up.
If you’re good with all that… go for it.

If you want larger tires for hard-core off-roading…. build an older Jeep so you don’t trash a $90k-$100k stock Jeep. Don’t forget a full roll cage.

There is so much more to it than simply fitting 40” tires to a Jeep.

 

[Zandcwhite]

Just keep in mind that if you go to 40” tires on 392 Wrangler, you will seriously change the on-road drivability. I don’t care what anyone says. I’ve been off-roading Jeeps for 20 years. Been down the road of trying to build on on-road Jeep that can run buggy trails.
Can’t have both.
The weightrotating mass and stiffer side wall of tires will dramatically affect the power and ride quality. Steering parts, knuckles, ect…will wear much quicker. It will vibrate after a few thousand miles if not right away.
If you off-road very difficult trails you risk breaking ring/pinion gears, drive-shafts. Questionable how long clutches in factory transfer case will hold up.
If you’re good with all that… go for it.

If you want larger tires for hard-core off-roading…. build an older Jeep so you don’t trash a $90k-$100k stock Jeep. Don’t forget a full roll cage.

There is so much more to it than simply fitting 40” tires to a Jeep.

The wife's 39s have been holding up great to daily driving and wheeling for 10k miles so far. No vibrations, road trips at 85mph for hours at a time, not taking buggy lines but running trails like the rubicon, John Bull, etc without issues. People act like 37s are good to go but going any larger and the jeep will just disintegrate in weeks. Obviously there's more wear and tear the bigger you go but do we really think there's that big a difference between a 37 and a 40?

 

[roaniecowpony]

Well played! Your arguments are simply too good for me to continue ?‍?. I surrender and bow to the infinite/collective wisdom of this supremely experienced and extraordinary group.

Obviously I'm stupid because I mistakenly interpreted his post, from 2 days ago, where he said “…I just installed a rear Fusion 60 on my Jeep…” If there was any doubt left, I showed my stupidity again when he said he bought this new trailer (pictured below), in November 2023, and a noticed 5-lugs without a sign of any locking hubs or a drive slug. Golly, how embarrassing!

My bad, I forgot where I was and should have never brought facts into the conversation. All of your arguments have convinced me to immediately sell my Jeeps, grow a mullet, get a ? enlargement, and reevaluate my entire life.



Huzzah!

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[SSWIM]

Just keep in mind that if you go to 40” tires on 392 Wrangler, you will seriously change the on-road drivability. I don’t care what anyone says. I’ve been off-roading Jeeps for 20 years. Been down the road of trying to build on on-road Jeep that can run buggy trails.
Can’t have both.
The weightrotating mass and stiffer side wall of tires will dramatically affect the power and ride quality. Steering parts, knuckles, ect…will wear much quicker. It will vibrate after a few thousand miles if not right away.
If you off-road very difficult trails you risk breaking ring/pinion gears, drive-shafts. Questionable how long clutches in factory transfer case will hold up.
If you’re good with all that… go for it.

If you want larger tires for hard-core off-roading…. build an older Jeep so you don’t trash a $90k-$100k stock Jeep. Don’t forget a full roll cage.

There is so much more to it than simply fitting 40” tires to a Jeep.

To say there is no change would be erroneous. But to say seriously changed is also a tad inflated, I believe. Absolutely if not done properly it would change drastically. Done properly and especially with what is available in today's market the change would be minimal.

My 392 with 40s goes down the road extremely well. At 85 it drives great. No vibration. No shake. Just point and go. As far as being reliable. I will venture to say it is every bit as reliable now as stock.

No disrespect. I also have been off roading for a fair bit. Things have progressed rapidly in the off road world and it has been very beneficial to the end user.

Sam

 

[Tank2112]

Stock 35” (33.75”) K02 tires are light weight (65lbs) and load range C for a reason. Adding a 90lbs, much larger tire with stiffer side wall, will definitely change on-road performance.
I’m just putting it out there for guys that haven’t had experience running larger tires.
Dana 44 can fairly reliably handle 37” tires over the long run. Sure, you can bolt on 40” tires, but it will effect braking, steering, stress on running gear… No way around that.
Remember lifting Jeep to accommodate larger tires also increases drive-shaft angles (wear quicker).
If I were going to dedicate to 40” tires, I’d install at least Dana 60/70 with manual locking hubs and 2wd option clutch-less transfer case.

Guy's running 40” tires, wonder what new 0-60 time is?

All depends on extended use of Jeep.

 

[JMP]

Well said! I don’t believe even I am capable of spewing this much hot garbage and venom in one nonsensical rant.

This is the issue with “Smashsmorshmins” ….On occasion, they find a way out of the garbage can.

Leaving someone for dead is a bit of a rabid statement…

Phenotypic variation exists among individuals and the variation is heritable. Those individuals with heritable traits better suited to the environment will survive….You have successfully thwarted Darwins plan.

This may be the best/funniest thing I’ve read on the website.

Good form dear sir. Good form.

 

[MSparks909]

I’ve got 40s on my 392. Running Dynatrac XD60s and PSC hydro assist. Put it this way…while I *can* drive it on the highway for long distances I choose not to. It’s been professionally aligned twice and even yet the steering is very twitchy above 45. Definitely due to the PSC kit. So I just trailer it when I go wheeling now. Tow rig is way more comfy than the Jeep ever was, including stock. So my Jeep is a trailer queen but that’s fine by me. At least I can get back home if I break something on the trails. I do wheel it pretty hard so that is a good peace of mind for me.

If your goal is a do it all daily driving 392 I’d leave it on 37s and call it good.

 

[SSWIM]

I’ve got 40s on my 392. Running Dynatrac XD60s and PSC hydro assist. Put it this way…while I *can* drive it on the highway for long distances I choose not to. It’s been professionally aligned twice and even yet the steering is very twitchy above 45. Definitely due to the PSC kit. So I just trailer it when I go wheeling now. Tow rig is way more comfy than the Jeep ever was, including stock. So my Jeep is a trailer queen but that’s fine by me. At least I can get back home if I break something on the trails. I do wheel it pretty hard so that is a good peace of mind for me.

If your goal is a do it all daily driving 392 I’d leave it on 37s and call it good.

That's interesting. I have portals and 42" tires. Plus the PSC steering also. I was rather suspect at installing the PSC kit. I had it on my JK with 42"s and Curries. It was like herding a snake down the road. The unit on my 392 is very very good. No twitch at all. Is it as good as stock, no, I would be a liar to say that. 42" on anything will change the dynamics of steering. I will say that it is a 9.5 out of 10 when compared to stock with 37"s (brother has one and we have done side by side comparisons). I can drive 85mph with confidence.

Possibly talk to Austin at PSC. Maybe you have, but he is a great resource.

Sam

 

[Infidel09]

Ha, I’d leave you broken on the trail if I saw you on 40’s with stock axles, on Pritchett. You have to ‘pay to play’ on the big-kid trails?

I've been keeping for a long time and never ran 40s... I have a 392 stock axels and want to go 38s... My wheels weigh 29lbs and the tires are 81lbs. Is it more of the weight being a factor or is it the diameter and wheel spin???

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