37" BFG KO2 on stock axles.

Boverlin · Jan 5, 2016

Hey everyone. I'm new to wayalife and new to the jeep world. I bought my 08 JKU RUBI about 6 months ago and I would really like to get that aggressive 37"tire look. I already did the "c" gussets & HD ball joints but other than that axle shafts, drive shafts, gears, ect is all stock. I'm running a 4" lift and 33" KM2's now. I wheel maybe once every 2 months and my daily commute is all hwy. Other than driving my mpg into the earth, is it a bad idea to run this particular tire? I've been told that I could run a 35"KM2 with no problems. The 37" KO2 only weighs 3 lbs more than the 35" KM2. I'm not worried about clearance issues because I have flat fenders and can trim and weld any pinch welds that need to be modified. Any "real life" advice would be awesome! I feel like shops sometimes just want to sell you on everything, which in the long run is not a bad thing, all I want to know is if I would be ok daily driving this tire. Thank you

TennJK · Jan 5, 2016

37" BFG KO2 on stock axles.

You would have no real problems with running the 35 KM2 on your current setup. But with having a 4 inch lift you should begin to consider a new driveshaft sooner than later. Regearing for 35s wouldn't be a bad idea, but with yours being a rubi, it's not completely necessary. But going with the jump go 37s is where a lot more money comes into play. So if you have the money to do a good bit of axle work and definitely regear, then go for it. But welcome to WAL. Glad to have you here

hinrichs · Jan 5, 2016

I would say you would be fine on 37s, since you are driving mostly highway. What type of wheeling do you typically do? You may want to regear since the 4.10 are not terrible, but not ideal which you will notice rather quickly.

RageKage · Jan 5, 2016

I have 37" Nitto Terra's on my 2014 JKU sport. Every single piece of my driveline is stock. No C gussets, no ball joints, absolutely zip. I've had them on for a little over a year now and I would say I use my rig about the same as you. Never done any real hard wheeling but it's a daily driver. Besides the lack of power I really haven't had any issues to complain about. No breakage, squeaks, leaks or anything of that nature. I'm sure all the parts are being worn and stressed like a mofo but hey, Ima keep saving up until something breaks. And my MPG is about an even 10.

Boverlin · Jan 5, 2016

hinrichs said:
I would say you would be fine on 37s, since you are driving mostly highway. What type of wheeling do you typically do? You may want to regear since the 4.10 are not terrible, but not ideal which you will notice rather quickly.

I mostly wheel in big bear ca. With the occasional high desert camping trip. If you're familiar with deep creek in big bear, I did that about 2 months ago and I have to say, that's about as hard as I want to go for now. But like I said, I think 20 out of the last 8000 miles I've put on the jeep have been off road, maybe 10 of which were crawling.

hinrichs · Jan 5, 2016

Boverlin said:
I mostly wheel in big bear ca. With the occasional high desert camping trip. If you're familiar with deep creek in big bear, I did that about 2 months ago and I have to say, that's about as hard as I want to go for now. But like I said, I think 20 out of the last 8000 miles I've put on the jeep have been off road, maybe 10 of which were crawling.

I am not, but speed and skinny pedal is what tends to break things more than tire size in a lot of situations. Since you already had the HD ball joints and gussets thats about all you need for the front. You are more prone to bending a rear axle flange as well, but should be fine if you watch what you are doing.

Boverlin · Jan 5, 2016

hinrichs said:
I am not, but speed and skinny pedal is what tends to break things more than tire size in a lot of situations. Since you already had the HD ball joints and gussets thats about all you need for the front. You are more prone to bending a rear axle flange as well, but should be fine if you watch what you are doing.

Thank you so much for your time and input. I hate driving my jeep fast! In my opinion, they just weren't made for it. I've had full long travel trucks in the past that were built for speed. It's time for me to slow down and enjoy time with my family and just crawl. Looking over the list of things that could break due to running 37's, I think I'm willing to just run them and if something breaks, fix it. Aside from the actual housing breaking, all the other stuff( chromolly axles, trusses, RCV's ... More ball joints...lol) it's all relatively cheap stuff to fix along the way. Anyway, thanks again!

Ddays · Jan 5, 2016

14Kyle74 said:
I have 37" Nitto Terra's on my 2014 JKU sport. Every single piece of my driveline is stock. No C gussets, no ball joints, absolutely zip. I've had them on for a little over a year now and I would say I use my rig about the same as you. Never done any real hard wheeling but it's a daily driver. Besides the lack of power I really haven't had any issues to complain about. No breakage, squeaks, leaks or anything of that nature. I'm sure all the parts are being worn and stressed like a mofo but hey, Ima keep saving up until something breaks. And my MPG is about an even 10.

10mpg!? :icon_crazy:

hinrichs said:
I am not, but speed and skinny pedal is what tends to break things more than tire size in a lot of situations. Since you already had the HD ball joints and gussets thats about all you need for the front. You are more prone to bending a rear axle flange as well, but should be fine if you watch what you are doing.

^^ This. I drove mine with a C-gusseted D30 & 37's for over a year without issues but was always super cautious with the skinny pedal.

Boverlin · Jan 5, 2016

TennJK said:
You would have no real problems with running the 35 KM2 on your current setup. But with having a 4 inch lift you should begin to consider a new driveshaft sooner than later. Regearing for 35s wouldn't be a bad idea, but with yours being a rubi, it's not completely necessary. But going with the jump go 37s is where a lot more money comes into play. So if you have the money to do a good bit of axle work and definitely regear, then go for it. But welcome to WAL. Glad to have you here

Thanks for the warm welcome and the input!

TitoJk · Jan 6, 2016

Im wanting to do the same had the same question im running 35 bfg on stock front dana 30 im wanting to upgrade to 37 i was told that i only needed the c gussets and really didnt need to sleeve it im swapping my gears this weekend to 5.13. Sleeves or no sleeves thats my question

RageKage · Jan 6, 2016

Ddays said:
10mpg!? :icon_crazy:

Is that good or bad? Lol I haven't done anything to try and counteract the fuel mileage drop. But I'm not worried about it regardless. It's a jeep, the most unaerodynamic square on wheels. If I wanted good gas mileage I would've bought a Chevy volt.... Notice how I didn't say Prius... 'Merica!

shadowpaige64507 · Jan 6, 2016

14Kyle74 said:
Is that good or bad? Lol I haven't done anything to try and counteract the fuel mileage drop. But I'm not worried about it regardless. It's a jeep, the most unaerodynamic square on wheels. If I wanted good gas mileage I would've bought a Chevy volt.... Notice how I didn't say Prius... 'Merica!

You could lower your rig down about 3 inches. That might help with the MPG, but you already stated that MPG don't really matter to you. Just out of curiosity why should a tall lift on your Jeep?

Ddays · Jan 6, 2016

14Kyle74 said:
Is that good or bad? Lol I haven't done anything to try and counteract the fuel mileage drop. But I'm not worried about it regardless. It's a jeep, the most unaerodynamic square on wheels. If I wanted good gas mileage I would've bought a Chevy volt.... Notice how I didn't say Prius... 'Merica!

LOL, I'd have to say that's on the bad side...I'm running 37's with 5:13's and average bout 15. Honestly you'd have to run the numbers on what a gear change would cost vs just putting up with the mileage. The payback might not be worth it in the long run if you're happy with it the way it is. You would be surprised in the increase in power though, especially if you're running an auto. I really noticed a difference in just going from 4:88's to 5:13's.

RockyJk · Jan 6, 2016

TitoJk said:
Im wanting to do the same had the same question im running 35 bfg on stock front dana 30 im wanting to upgrade to 37 i was told that i only needed the c gussets and really didnt need to sleeve it im swapping my gears this weekend to 5.13. Sleeves or no sleeves thats my question

Don't sleeve it, the sleeves won't stop the housing from bending at the diff

RageKage · Jan 6, 2016

Ddays said:
LOL, I'd have to say that's on the bad side...I'm running 37's with 5:13's and average bout 15. Honestly you'd have to run the numbers on what a gear change would cost vs just putting up with the mileage. The payback might not be worth it in the long run if you're happy with it the way it is. You would be surprised in the increase in power though, especially if you're running an auto. I really noticed a difference in just going from 4:88's to 5:13's.

Yea I plan on regearing and upgrading the innards of the axels in the future. I would absolutely love the horsepower back and an increase in MPG. I'm leaning towards 5.13's and a locker. Everyone keeps telling me 4.88's are good enough but I don't like good enough. Lol Thought about a spool in the rear end but haven't really decided.

RageKage · Jan 6, 2016

shadowpaige64507 said:
You could lower your rig down about 3 inches. That might help with the MPG, but you already stated that MPG don't really matter to you. Just out of curiosity why should a tall lift on your Jeep?

Honestly it's just what I wanted. It's only a 6.5 inch lift [emoji23] I see a lot of rigs on 37's and 40's that only have 4 inches. I just like being different and doing things my own way and in my own direction. I've always been that guy that goes against the masses.

Ddays · Jan 6, 2016

14Kyle74 said:
Yea I plan on regearing and upgrading the innards of the axels in the future. I would absolutely love the horsepower back and an increase in MPG. I'm leaning towards 5.13's and a locker. Everyone keeps telling me 4.88's are good enough but I don't like good enough. Lol Thought about a spool in the rear end but haven't really decided.

5:13's all the way. Ran 4:88's but went with lower ratio when I did axle swap. Puts rpm's more in the sweet spot. Very little negative impact on mpg.

OverlanderJK · Jan 6, 2016

14Kyle74 said:
Honestly it's just what I wanted. It's only a 6.5 inch lift [emoji23] I see a lot of rigs on 37's and 40's that only have 4 inches. I just like being different and doing things my own way and in my own direction. I've always been that guy that goes against the masses.

Are you really a mechanic? You haven't said many smart things in this thread.

RageKage · Jan 6, 2016

37" BFG KO2 on stock axles.

OverlanderJK said:
Are you really a mechanic? You haven't said many smart things in this thread.

So because I have my personal preferences about the things I like and how I'm building my jeep makes me not a mechanic? What exactly have I said that "wasn't smart?"

Good to know... I forgot I was here trying to impress or convince people about what I do for a living.

WJCO · Jan 6, 2016

14Kyle74 said:
....upgrading the innards of the axels in the future.... I'm leaning towards 5.13's and a locker. Everyone keeps telling me 4.88's are good enough but I don't like good enough.......

Are you talking front OEM D30 axle? 37s......5.13.......locker.....

14Kyle74 said:
So because I have my personal preferences about the things I like and how I'm building my jeep makes me not a mechanic? What exactly have I said that "wasn't smart?"

See above. Just curious.....

37" BFG KO2 on stock axles.

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