Regret 37s?

[DavidArmen]

Been running small 35s (315/70R17 KO2s) since July and I honestly don’t regret it. The C Load 37” ko2s weren’t released yet so I’m happy with my setup! Running them with the dynatrac Endurosport with the mopar front LCAs and a set of Teraflex 1/2” front coil spacers for leveling. My jeep is way more capable than I am and I have zero regrets. Having said all that, it is in the back of my mind to upgrade to the new, aforementioned 37” ko2s in a few years, especially since they’re quoted by Bfg as only being 1-2lbs heavier than my current 35s.

Screenshots from BFG’s website:

^ 315/70R17 Load Range C ^

^ 37x12.50x17 Load Range C ^

Only 1.44 pounds heavier. I’m not sure how accurate that actually is and if it is, how they managed that.

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[Rodeoflyer]

I love everything about them except the price tag

 

[Hercules]

Good looking jeep...I have a similar setup and know of a few people on here who offroad and daily drive jlur's that regretted going from 35s to 37s and sold them at a sizeable loss to go back to 35s. It's not cool to admit in this thread, so you won't find them posting here. Their reasons were...37s made the jeep noticeably more sluggish during braking, acceleration, offroad down low power, lost top gearing on the hwy. They were going to spend another $3k on regearing/spare tire carrier and could run 90% of the trails on 35s that they were doing on 37s. All things considered, it wasn't worth the total cost to gain 1" of clearance with 37s.

I have a 6 speed, rubi axles/fenders on 315/70/17 KO2's and would eventually like more agressive, lighter weight 37s bc I bought a used honda accord daily driver and enjoy wheeling(like load d Yokohama G003 or km3)for another inch of clearance and to fill the fender gap. However, it's realistically going to cost $5k going to 37s bc I'd want to regear, upgrade tire carrier, get wheels with less backspacing + cost of 37" tires. I'd also be very tempted to get the AAL fender chop kit and upgrade tie rod/draglink. I'm still very tempted if I could somehow find a deal on used 37's and sell my ko2's.

Those 35s then in these pics? I'm assuming with a 2.5 in lift?

 

[Nerdflex]

I'm seeing people with Mopar lifts and 37's, with the rear axle perfectly centered in the wheel well. Mine seems to be too far forward. Are people adding different control arms and just not mentioning it, or did I do something wrong? I seems like there is no way to get it centered without longer arms.

 

[Rodeoflyer]

I told my installer to lengthen the rear lowers 1/2'' over stock.. He kinda argued with me and finally said he would lengthen them 1/4'' over stock. My rear wheels look pretty centered with the 37's. I also have an adjustable trackbar and have my rear centered laterally. If you don't adjust your axle center that could be a problem as well.

What's the passenger side look like?

 

[mgroeger]

I'm seeing people with Mopar lifts and 37's, with the rear axle perfectly centered in the wheel well. Mine seems to be too far forward. Are people adding different control arms and just not mentioning it, or did I do something wrong? I seems like there is no way to get it centered without longer arms.

That def does not look right. Did you tighten the control arms to spec while the Jeep was up on a jack or jackstands? If you did that's the problem. You need to have everything loose (upper and lower front and rear bolts) with the Jeep sitting on level ground THEN tighten everything to spec. If you tighten them while up in the air you will get a "false lift" and I believe what you are seeing with your axle.

 

[jessedacri]

That def does not look right. Did you tighten the control arms to spec while the Jeep was up on a jack or jackstands? If you did that's the problem. You need to have everything loose (upper and lower front and rear bolts) with the Jeep sitting on level ground THEN tighten everything to spec. If you tighten them while up in the air you will get a "false lift" and I believe what you are seeing with your axle.

This is good advice but I'm not sure that should make too too much of a difference on wheel/axle position - the Mopar lift uses all stock control ams in the rear so the more lift you get the closer the wheel moves to the front of the vehicle. In the scenario where they're torqued too tightly while on a lift it'll create binding but I don't know if it'll create so much binding that the weight of the vehicle won't overcome it. I would highly recommend getting a set of adjustable control arms from Metalcloak or something to bring it back into spec. I just did so and my wheel moved to the center of the wheel well in the rear.

 

[Nerdflex]

Passenger side is the same. I do have adjustable trackbars to install, but I can't see how that will help front to back.

Thanks mgroeger. I will try what you said, but I'm thinking that I will need to look at some adjustable control arms as jessedacri suggested.

 

[BamaJeep]

Been running small 35s (315/70R17 KO2s) since July and I honestly don’t regret it. The C Load 37” ko2s weren’t released yet so I’m happy with my setup! Running them with the dynatrac Endurosport with the mopar front LCAs and a set of Teraflex 1/2” front coil spacers for leveling. My jeep is way more capable than I am and I have zero regrets. Having said all that, it is in the back of my mind to upgrade to the new, aforementioned 37” ko2s in a few years, especially since they’re quoted by Bfg as only being 1-2lbs heavier than my current 35s.

Screenshots from BFG’s website:

^ 315/70R17 Load Range C ^

^ 37x12.50x17 Load Range C ^

Only 1.44 pounds heavier. I’m not sure how accurate that actually is and if it is, how they managed that.

I’ve heard part of the reason the C load KO2s are so light is they are skinnier than other 37/12.5 brand offerings. The tread is the thickest and heaviest part of the tire. By reducing the width they can save a good bit of weight.

 

[dougrobling]

So I’ve read through all of these posts (several others as well) and I would like to hear opinions on my current plan…..

I have ordered a 2023 Rubicon Unlimited with the Xtreme Recon package. I had intended to just buy BMG KM3’s in the same 315/70R17 that comes from the factory, but after reading these posts I have been convinced to move up to 37’s….

Assumptions:

The 4.56 gearing that comes on it will be more than adequate. (Based on the consensus here that seems to be that 4.10 is doable, with 4.88 being ideal)

It will come with the Rubicon high clearance fenders and a Mopar lift (1 1/2”) that falls just short of the Mopar 2” that everyone here says has ample clearance. So I’m thinking that BFG KM3 (smallish 37’s) will clear in the front but probably still rub on the plastic bump in the rear.

If I do have rubbing, my plan would be to first heat and flatten the bump. If that doesn’t do it, I would have the options of either an addition to the rear bump stop, or fender chop/high clearance fender set….(depending on where and how much contact I have)

If I’m going big I would also like to go with the wider 37x13.5R17 tires. The Mopar bead-lock wheels that are a part of the package are 8”, but become the recommended 8.5” minimum when used with the optional beadlock rings. With a backspacing of 4.4” I think these should work as well.

I would plan on the Tazer for tire size change and stop-start disable.

I am looking for the best of all worlds. Great performance off-road, and tame enough for long highway trips….

My only other concern is garage clearance. These posts show 75” as full height with 37’s and a 2” lift, but I have ordered the one touch sky top and can’t find anywhere how much more it sticks up when open. It looks like 4”-5” additional which would just clear, but if it’s 6” or more I would have a problem….

Thanks, and any advise is welcome as I would prefer to do this only once….

 

[Rodeoflyer]

You'll be fine on 4.10's and those lightweight BFG 37's and 13.5's on an 8'' wheel in TN atmosphere. I can tell you that much. You're on your own with the other concerns. We can't let you get it right the first time when we all had to change everything 4-5x

 

[damageinc321]

View attachment 624516 View attachment 624516

I'm seeing people with Mopar lifts and 37's, with the rear axle perfectly centered in the wheel well. Mine seems to be too far forward. Are people adding different control arms and just not mentioning it, or did I do something wrong? I seems like there is no way to get it centered without longer arms.

I'm seeing people with Mopar lifts and 37's, with the rear axle perfectly centered in the wheel well. Mine seems to be too far forward. Are people adding different control arms and just not mentioning it, or did I do something wrong? I seems like there is no way to get it centered without longer arms.

I'm seeing people with Mopar lifts and 37's, with the rear axle perfectly centered in the wheel well. Mine seems to be too far forward. Are people adding different control arms and just not mentioning it, or did I do something wrong? I seems like there is no way to get it centered without longer arms.

Yeah yours look kinda pushed forward I had mine dealer installed but added front and rear adjustable synergy track bars, not that that should have an impact. Mopar lift with 37x12.5x17.

 

[kah.mun.rah]

So... anyone regret their 37s?

Nope

 

[kah.mun.rah]

I'm seeing people with Mopar lifts and 37's, with the rear axle perfectly centered in the wheel well. Mine seems to be too far forward. Are people adding different control arms and just not mentioning it, or did I do something wrong? I seems like there is no way to get it centered without longer arms.

Something looks off. This is the JL I had with 37s and the Mopar lift for comparison:

 

[Rodeoflyer]

Yeah yours look kinda pushed forward I had mine dealer installed but added front and rear adjustable synergy track bars, not that that should have an impact. Mopar lift with 37x12.5x17.

Oh man I wanted a white JLUR.. couldn't find the right one in the timeframe I wanted it.

I absolutely love your jeep.

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