Good day to all. I have a few questions that may spur a little debate and it has to do with Tire size. I recently bought a 2011 Wrangler Sahara 6spd Manual with RIPP Supercharger and 4.88 Gears that has a 4.5 Inch Icon lift (Springs and shocks), some Rock Kralwer adjustable control arms and track bar, a JKS Draglink flip kit, and JKS Lower control arm brackets. The original owner had just purchased some 37x12.5R17 Cooper Discoverer STT Pro prior to selling the jeep and they only have about 3,000 miles on them total. The pinch seam was never cut but it is quite obvious it will need to be done before going off-road or the rear axle needs to be adjusted back a little. I have read the many stories or opinions concerning jumping up to 37s and I can attest that I believe the previous owner drank the koolaid and felt like as long as he babied it on-road that the 37s would be fine.

I have only owned the jeep for about 2 weeks but I have noticed a few things that will need replacement and soon. The front drive shaft needs a new CV joint due to the high angle of the lift and tires, and the Draglink Tie Rod and the Draglink bar rubber boots have ripped and need replacement. The front Dana 30 axle has the C Gussets welded in place but no other modifications. My eyes began to get really wide when I started looking at prices of Adam's drives shafts, a Dynatrac Pro 44 and a JK44 35-spline axle shaft bundle kit. The upgrades seem never-ending to accommodate the larger tire. But is it truly necessary?

Now that you know a little background-

Is there really that much difference between a 35 and a 37 especially when comparing weight and the damage the weight causes? A 35 Nitto Trail Grappler rated 77lbs and my 37 STT Pro was 83 on the charts at discount tire. The Falken was 80lbs. To me both a 35 and 37 will cause some steering headache and possible require Assisted steering. The 315/70 STT Pro (34.57 inch) was rated at 68lbs so that is much better and probably would give some relief to the suspension components.

Would a 35 look foolish with a 4.5 inch lift? I am considering looking at buying 3 inch springs to bring it back down. I just need to speak with ICON to see what the possibilities are and what all I need to do. I am looking for the perfect fit without compromising the ability to go down the trail and looking good while doing it. I don't want to purchase an entire lift kit- just need to make a few adjustments.

Has anyone else dropped back down from a 37 to ease the pain on the wallet? If so, what other considerations do I need to be thinking about when doing so. I believe the 3.8L with a manual can still handle the 4.88 with 35s. So I shouldn't need to regear. It feels very peppy even with the 37s and all the extra weight of the poison spyder bumbers and winch.

Lastly, If anyone is interested in purchasing a nearly brand new set of 37's- I am looking to wheel and deal. I have 5 with your name on them.

Chris

 

Yes, if you want it to drive nicely on the pavement.

Meh, not that big of a difference IMO.

Yes, I think it would. That's a lot of open wheel well to fill. There's no reason you have to stay with Icon springs. If you want to go back to 35s, a good 2.5" spring would be a nice combo and would likely net you a bit more, maybe 3" of lift. No, you don't need to purchase an entire new kit. Will you lose a little performance off road? y, a little bit. You might run across some big obstacle where that bit of extra tire would make a difference, but 97% of the time you probably wouldn't notice it. Course, dropping down to 35s doesn't alleviate you from addressing your steering component upgrades.

What do you think you want for those?

It takes quite a bit to do 3.5"+ lift with 37s. Just kind of the nature of the beast and about everything needs to be addressed. Most people don't take the time to do it right, or are just ignorant in what really needs to be done. They just care about it looking cool. If driveshafts are giving you sticker shock, don't look at ball joints, tie rods and drag links. Does that jeep have adjustable rear control arms?

You obviously see the weakness in running 37s and a D30 axle. It's not the end of the world, it can be done, but it's more likely to not handle a beating very well. I would tell you that I've run 37s and a Rubi44 axle, which isn't a whole lot better, for years. Granted, I've done a lot of work on the axle.

I'm picking up new axles tomorrow. Come buy my Rubi44s!!

 

The extra lift was to keep factory flares and have 37's. I've got friends that drank the 37" koolaid and now they don't drive the Jeri because it's more work than fun to keep it driving nicely on the road. I've been hung up on 35's and wouldn't want to go up. They're big enough to get me into trouble without being so much work that I'm buried with maintenance or dread the thought of taking it anywhere.

I vote yes to downsizing, but I've always had more fun on 35's because it makes you work a little more than 37's rolling over everything.

 

My experience has been similar, but just up a step. Friends built to D60s and 40s, jeeps became trailer princesses and never get used. I love my 37s but have zero desire to go further. I'd build myself out of the garage. It's pretty much the same rule of thumb right on up the line. 35's will do about 95% of what 37s will do, 37s will do about 95% of what 40s will do. Guess what, if you have 40s, you'll run across people with 42/43s. I side with Karl that 35s are nice on multiple levels for most people, and pairing with a 2.5" lift is best IMO. That said, you can damage a D30 just as easily with 35s as you can 37s. You just need to use your head and be sensible.

Option 1) get some rear arms and scoot rear axle back, trim pinch seam, replace front DS and freshen up steering components, have fun with that axle keeping in mind a future upgrade.

Option 2) swap springs, go to 35s, replace front DS, freshen up steering components, have fun with that axle keeping in mind you might have a future upgrade.

There's really not a whole lot of difference, and your use of the jeep will dictate a lot.

 

You can also just swap out to flat fenders and lower your lift to a 2.5 inch one with some new springs from Rock Krawler, some new Falcon shocks too to make it ride nice.

You probably want an aftermarket drag link and tie rod, even if you go down to 35's.

You can still bend a Dana 30 Axle with 35's, I know from experience.
I had to replace my front drive shaft with a 2.5 inch Rock Krawler lift too.

 

I appreciate your thoughts on this. I know either way I have to spend some money to make it right. I don't have a lot of opportunity to wheel it very much so it will be utilized as a daily driver about 80% of the time with shared duty with my DRZ 400. I just want to avoid getting nickel and dimed to death and want to do it right from the beginning. That being said- I need to be conscious about how much I spend as I had convinced the wife that the Jeep was perfect as it was just before the purchase.

I do believe it has adjustable rear arms but I haven't gotten under there to try to adjust them. I know that may cause other alignment issues with the diff and the track bar so I will see what I can do to make it better. My goal is to eventually have a 44 on the front but that will probably be a year out. I was planning on updating the ball joints and add lockers at that time as well. Is there a best way to make the proper adjustment to the Rear arms? I don't have a service manual yet and don't want to make things worse just by scooting things here or there.

Other than the rear arms, It looks as though the only other thing I really need is work on the Draglink and Tie Rod (it was the JKS Drag link but I think I will go Terra Flex this time around) and add my high angle Terra flex RZeppa CV Joint on the front Drive Shaft. The High Angle CV should be here Friday. I know it is just a Band-Aid fix and I do plan on going 1310 or 1350 Adam's or Tom Woods on the Drive Shafts in the future. Again- Little upgrades over time.

Falcon is putting out a decent product for sure. I like the ride of my Icon 2.0 VS and everything seems to track very well down the road with no death wobble or bump steer. The jeep had an aftermarket JKS Drag link and tie rod but both boots ripped- I am not real familiar with it and was looking to see if they could be repaired but it looks like most just replace the whole bar. JKS only offers it in a kit but lacks the tie rod and comes with the additional Trackbar bracket. I don't really need those extra pieces just need the bar and a new tie rod. Or just spend $400 bucks and get the whole bar and tie rod from Terra Flex.

I do think my wife would appreciate the lower lift of the 2.5 to make it easier to get in the Jeep. It seems either way I go I have to chase a few new purchases chasing bump stop sizes, new shocks, flares and springs.

I just worry about what other items may start wearing out if I chose to keep those larger 37s.

I will suppose sticking with the 37s for now is the best choice with my light driving and start building up the other items around them to make it stronger. Choices Choices Choices.....

 

Thanks for the vote! I don't plan on keeping my rig in the garage in fear of breaking it. I don't mind maintenance but I don't want to keep chasing the worn out parts due to a heavier tire. I just questioned most of the response from other forums that is was all due to the weight of the tire and that 35s are the best option. The only problem I saw was many of the true 35 Nitto were just a few pounds shy of the 37 STT Pro. There was a 15lb difference in the 315/70 STT Pro so I could see where the 315 rolling mass actually play a factor in being easier on the components.

Back in the day when My mom would buy me new shoes, I always showed her how much faster I was than with my old shoes (Reality- I was never faster). Funny how "37" may give you a false sense of being able to overcome something that a "35" would have no issues with.

 

If you DO have rear arms, or ever plan to get some, it's not really an alignment thing. The waterfall issue moving axle back is typically then create a clearance issue with the rear sway bar links, so you move the rear sway bar back, which creates a clearance problem with the factory exhaust. Other than that, the axle isn't shifting side to side and the pinion angle gets corrected with the upper rear control arms.

I think Karl has rebuilt one of those TF rzeppas before. Not sure you have to consider it a band-aid. It could be perfectly suitable for your use. Aftermarket is typically better for playing in big rocks, but not everyone is doing that.

Some reason to not just replace the DL end on that JKS DL vs. the entire DL itself? Is that TR aftermarket? You may be able to just find some boots that will work. If it's factory, probably better off just replacing it. You can build a really nice TR out of 1.5" aluminum with 1-ton ends for right around $200. I say "build", but you're just ordering the aluminum which comes bored and tapped and then literally screwing the 1-ton ends in. Not hard at all and you end up with a nice TR. Bora Bora has a good thread on here about it.

 

IF you do decide to downsize the coils, don't forget that there might be a few other things to consider. Like the difference in the steering geometry between Flipped and Stock, and adjusting the trackbars to re-center the axles, and adjusting the CA brackets to lower the caster, and ...

So yeah, I agree with the others, 2.5" coils would be the better choice if you drop to 35's. Just a suggestion to think it through.

 

So I do not have adjustable rear arms. Bummer. But I will look to buy a matching set of Rock Krawlers that I have on the front.

As for the Draglink and TR, I was hoping I could just buy new boots..I am just not familiar enough on where to source them. I will call the local autozone for ideas. Here are the pics of the DL and TR.


DL side

TR end
.