We did WHAT??! How far can you go on 37s with Sport axles?

Have we lost our ever-lovin' minds? 37" tires on a Dana 30 & 35? We know what the internet will say, but we are on a mission to push our Jeep Wrangler Sport Unlimited to its limits with these giant Mickey Thompson tires! Drop a comment below and let us know what YOU think. Have you experienced this? Do you have regrets?
Check out our other videos in the link below to see just how hard we can wheel. And be sure to subscribe to follow along and see what happens next!
• 4x4 Madness: Off Road ...

[@GypsyJeepin]

Well, you both know full well some of the crazy shenanigans Gypsy has been involved in and how much I can yeet! She was on stock D30/35 axels/gears and open diff with 4in lift and 37s for 75k miles before we did the axel swap. No bending or damage. Only upgraded because I wanted lockers!

[@johnnastevens2640]

You can do ittttttt! 😂 We ain’t skeered

[@smileyguyz]

I absolutely agree that it's all about the driver. If you try to drive it like a rock bouncer with the 37s, yeah things are gonna break and bend. Driver mod above all else

[@Expedition-FullSend]

100%! I try really hard not to send it unless there is no other option, and even then, there are usually options. ;)

[@donniepitts1646]

I've been running 37's on sport axles, dana 30 and dana 44 with 4.88 gears. I do rock crawling about 4 times a year. I have broken two axles but in reality, that's not too expensive compared to going to 1 tons and everything else required. I have a 6 sp manual and it crawls great with all my friends with 40's and 1 tons.

[@Expedition-FullSend]

Definitely agree! Our thoughts exactly! Dozens of axle shafts replaced before paying for tons.

[@jeradmiller4575]

Fun fact: all four door JKs (JKUs), except early 07 models, came standard with D44 rear axles

[@Expedition-FullSend]

WELLLL, clearly we did NOT know that, and I am mortified. I swear I saw that when I looked up my VIN after I bought it a few years ago. We are so grateful to you for bringing that to our attention! I guess it's only HALF as bad an idea as we originally thought. 😜

[@WBOS72]

As long as common sense stays in the pic, you will be fine. Subscribed.

[@Expedition-FullSend]

We appreciate you following along!! We're looking forward to bringing you some quality content. :)

[@ghernandez6457]

Damn I thought I was crazy runnning 38s on JLUR D44s with RCVs.

[@Expedition-FullSend]

That’s not crazy in our book!!

[@sixpest]

Its the same housing as the dana 44 so its been there and done that; the actual difference is that the dana30 axles have no real gears inside of them so they can blow up

[@jonaathansimons7938]

If you're not locked, the D30 will live with a moderate skinny pedal. The first weak link is the axle U-joints. There are ways of addressing this: inner full circlip joints, Almost alloy weld on caps, or of course RCV shafts. A high spline count carrier (GrizzlyLocker, etc.) combined with axle shaft mods nets great results. The next weak link becomes the ring and pinion. Again, a moderate pedal greatly extends the lifespan of your parts. Bending the housing on a D30 generally only happens with high abuse; a truss or inner sleeving the tube (I pressed in and rosette welded hot rolled tube inside my XJ axle tubes) alleviates much of that worry. If you don't sky it out you should be OK.

[@Expedition-FullSend]

Thank you, this confirms what we were thinking as well. Truss and sleeving has been discussed, and may happen. Honestly though, with the 5:13 gears, I rarely have to gas it. I just take my foot off the brake and she'll crawl pretty much anything. Hope you'll follow along!

[@clanrubicon]

Run it! You won’t know until you do. I’ve never run 37s on a 30. Largest size tire was a 35. Axle was in my XJ. Broke both axle shafts on the Rubicon before getting to any of the hard obstacles. In my experience, it’s just a matter of time before a Dana 30 lets go. I wouldn’t dump money into building up a 30 for 37s. You’ve got free 5.13 gears and 30s of today are an improvement over 30s of yore. Run what you got and start putting money towards a better axle in the meantime. You’ve got nothing to lose and the experience will make you a better Jeeper.

[@Expedition-FullSend]

Thank you! That is precisely our line of thinking. It's likely that the weak spot will be the U-joint/axle shaft, and that can be replaced fairly cheaply. We talked about doing chromoly shafts, but that shifts the weak point to the ring and pinion, and we'd like to avoid breaking that if possible. That leaves the axle housing as another weak spot. I think a truss might help give us a slight advantage on that end, but it will eventually give out, as you said. We're going to have fun trying to make it last as long as we can!

[@st5637]

Why don't you sell the existing axles while they are still good and unstressed.

[@BlueOxDiesel]

Yes when you measure the height after at the trailer hitch you can see the rear axle it’s a Dana 44

[@Expedition-FullSend]

DOH. 😅We've got another video coming out soon that addresses this.

[@mikemay7134]

I have a 13 two-door sport I've been running 37 bfgs for over 7 years, Dana 44 in the rear with a mini spool Yukon chromoly axles and Dana 30 in the front Yukon axles lock write Locker 488 gears Adams Drive Shaft CV delete, had a guy here in Florida break into the computer unlock it and create 18 so that I can run the Spool in the rear no lights or limp mode I will the hell out of my Jeep, yes every once in awhile I break something but it's usually an Axel not a big deal the Yukon chromoly axles can take pretty good punishment, don't underestimate a Dana 30 I know people will laugh but when it's all said and done my Jeep is extremely lightweight and that's the thing I was really trying to achieve mostly flat trail riding in a lot of mud here in Florida

[@mikemay7134]

People will also say that you cannot run a spool on a JK in the rear you can if you get the delete in the computer there's a guy in Middleburg Florida tuners Inc. Does mostly Fords my jeep was the first one that he experimented with it took a long time but he was able to break into the computer and create a tune to run a spool, now that he has the program he's done a few more

[@FahimibnDawud]

​@mikemay7134 care to post his info?

[@mikemay7134]

@FahimibnDawud his name is Tony his business is tuners ink. Middleburg Florida

[@79staceface]

I need to know.. how do you drive 70mph and take your hands off the wheel? My ‘14 JK is all over the lane at that speed 😅.

[@Expedition-FullSend]

I am forever wondering the same thing. I think mine is the exception to the rule! HAHA I know for a fact you are not alone. Our other Jeep is like yours - it's scary to drive sometimes!! Add that Oklahoma wind and you could be blasting off to the moon if you hit a pothole wrong. Coincidentally, it's also a '14. Wonder if there's something to that?

[@jchildress3476]

Where at in Oklahoma are you? I'm OKC and haven't seen y'all.

[@Expedition-FullSend]

We're also in OKC, and we actually were at Axcel's even on Saturday! We're even friends on FB. LOLOLOL We just haven't had a chance to wheel with y'all yet, so that's probably why it doesn't click. Soon. :D

[@Lefishn]

I'm new to jeeps and just bought my first Wrangler. So you went to 37" tires and are getting 4mpg better than the 35's???? How's that possible

[@Expedition-FullSend]

Hi there! We have 5:13 gears in this Wrangler. That killed the MPGs when we were running 35s. When we went to 37s it brought the ratio down which brought the RPMs down which then brought the MPGs up. With 35s the RPMs ran about 3300 at highway speeds but going to 37s brought that down to around 2700. That's a HUGE difference in effort hence the increase. Does that make sense?

[@shanevanorder2644]

Do jeeps come standard with the engine light on

[@Expedition-FullSend]

HA! It sure seems that way. It's okay though - it makes them go faster! ;)