Experience with 39” BFGoodrich KM3’s Mud Terrain Tires

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I’m still in the fence!!! Get $110 off on them through Costco right now, but dammit do I get 37 D rated or 39 C rated!?!?!?!?!?
If you get another set of 37's, you'll always think of the 39's. If you get the 39's, you'll forget all about 37's the moment your Jeep pulls out of the shop.





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Is anybody running these KM3 39s with Rubicon stock gearing and axles?????

I currently have 37s and I here about 37s needing to be geared but I can’t tell any different in power between my 37s and the stock 33s.
I will also not be doing any hard off-roading.
 

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Welp, I’m joining the 39” club! I ordered from Costco.Should be here in 10 days or so. I’ll be running them on the stock rubicon wheel, with 1 1/2” wheel spacers, 2” rear lift, 2 3/4” front lift, plus a 1 1/4” body lift on the stock axles. Fenders are chopped and wheel wells are massaged.
 

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Is anybody running these KM3 39s with Rubicon stock gearing and axles?????

I currently have 37s and I here about 37s needing to be geared but I can’t tell any different in power between my 37s and the stock 33s.
I will also not be doing any hard off-roading.
I've been using them for close to a year now while doing the Hard Lines and keeping it operational for my daily driver. I just upgraded axles to tons as of this week however I was using OEM D44 axles. I had them built to the max with truss, gusset, RCVs, Dynatrac ball joints, PSC hydro assist steering, RPM 2.5 ton aluminum tie rod and drag link and geared to 5:13. Well, let's just say that fate caught up with me. Started as a minor rear pinion seal leak and ended with broken rear ring gear. The teeth of 5:13s just didnt have enough meat on them and to still be able to fit into a D44 housing, so eventually a few teeth decided they couldn't go on. I pushed the envelope to see how long a built D44 would last running 39s and it can be done, just keep an eye on the clock. Because it wont stop ticking.......

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Welp, I’m joining the 39” club! I ordered from Costco.Should be here in 10 days or so. I’ll be running them on the stock rubicon wheel, with 1 1/2” wheel spacers, 2” rear lift, 2 3/4” front lift, plus a 1 1/4” body lift on the stock axles. Fenders are chopped and wheel wells are massaged.

Any updates?
 

Glamisfan

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Not in yet. Fingers crossed they show up soon!
 

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No, I bought a set of used Goodyear MTR‘s 37 x 12 50 x 17 a few months back and have been running those. It’s a JLUR and I really can’t tell that I’m running 37‘s on this thing. The thing I don’t like about my current tires is they just ride too rough. I’m hoping that going from a D load range to a C load range will help the ride at least a little bit. And with my small lift and chopped Fenders the 37‘s just don’t look big enough to me anymore. I just put a 1 1/4 inch body lift on this past Friday so I won’t have any rubbing issues. I also cut out the pinch seam on the rear wheel wells. I do a fair amount of off roading, but it’s honestly pretty mellow. I’ve done two rides with Jeeps and literally had no more than two minutes total of rock crawling over eight hours. Mostly just medium speed desert roads. I’ve got 50 years of off-road experience so I’m counting on my knowledge of tire placement to keep me from breaking things? Fingers crossed!
 

DLW

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So for everyone on these 39's I assume you need to trim the rear pinch seam for proper clearance? Mainly in the rear lower front/back area?
 

DLW

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Thanks 4xnaz for the quick feedback!
If that is the only piece that needs trimmed, that is not bad at all.
Looking at the final result, seems like you trimmed off about 2" or so.
I have the AAL inner liners and I think if I had to trim up further I would have to remove them and opt for something different.
 

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Thanks 4xnaz for the quick feedback!
If that is the only piece that needs trimmed, that is not bad at all.
Looking at the final result, seems like you trimmed off about 2" or so.
I have the AAL inner liners and I think if I had to trim up further I would have to remove them and opt for something different.
That was with 38's but since moved up to 39's but didn't need additional trimming.
 

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I’ll be putting my 39‘s on this evening at Costco. I’ve got a custom shocks set up so I’m only running 3/8 inch bump stop in the rear so I had to cut all the pinch seam. For anybody that’s got 2 inches of bump stop added, I think just those lower corners would be the only trimming needed?
 

Glamisfan

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WOW WOW WOW! I am absolutely floored at the improvement and ride quality! I drove down a section of road that my extremely worn Goodyears felt like riding in a big rig. These tires felt like I was in a brand new vehicle again! Night and day difference!

I did have one little issue at Costco that they said they could not mount and install the tires with me running wheel spacers. then they told me that if I let them remove the wheel spacers that they could mount everything up and I would just have to put the wheel spacers on myself at home. I said great do it! I’m gonna flex it out like this just to see what it looks like but I am 99% sure I need the spacers back on. I’m run stock wheels still.. Pictures below.. If you see something a little off it’s because the rear wheels have vinyl overlays on them that I’m trying to decide if I wanna run with those or take them off?

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