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Discussion Starter #1
Trying to pose this as a straightforward question but there are a lot of angles to this for me. Interested in peoples’ experience/opinions.

Should I run 33’s and re-gear back to 4.10 (or live with running 2800 rpm in the slow lane) or up-size to 35s?

The Jeep:
2017 JKUR I bought used with 15k miles (dealer trade in)
Rock Krawler 2.5” lift with Bilstein 5100s
Fox ATS 2.0 steering stabilizer.
G2 Performance 4.88 gears
Tom Woods shafts f&r
Currently wearing OEM wheels and tires. Also have a partial set of 33” tires on JLUR wheels

My goals/philosophy of use:

The Jeep will be used to drive around town on occasion by both me and my wife and will be used almost every weekend for fishing, backpacking, and hunting trips. These trips will usually involve several hours of highway travel in each direction.

I’m 50+ years old and I’ve done the crazy “dump money into a hole chasing problems and then sell it” thing already more times than I should have with cars and 4x4s.

I want something that will be very reliable and well mannered, but will get me to my buddy’s place on a remote cove in Baja when the roads are washed out or get me deeper into a canyon so I can get a better head start on opening day of quail season. More so than my F-150, F-250, or Ranger FX4 LII can/could do. (But more comfortable than my FJ40, CJ5, CJ7, or Scout).

I’m not looking for rock-bashing, belly-dragging, wheel-bending, axle-snapping rock crawling just for the sake of rock crawling. (BTDT). I just want a cool Jeep that gets me places and keeps a smile on my face and doesn’t piss off my wife.

Very interested to hear from people that have gone from 33’s to 35’ and whether it affected reliability or general maintenance requirements. Also would love to hear from anyone that ran 35s and decided to go back to 33s and why.



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33's are basically the stock JK-sized tire. 35's fit very well and would match the 4.88 gears. With a JKU, you need a bigger tire. If I'm limited to those choices for a JKU going offroad, I will pick the 35's. I'll also recommend that you make sure you have a good belly skid.


Your axles should be perfectly fine, strength-wise to handle 35's with no reliability issues
 
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What Don said, you need 35s with a 4 door. A 2 door would be okay on 33s as far as ground clearance but not a 4 door.
 

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The problem with 35's...
I have 2.5 lift and 35's and wouldn't go back to 33's. The only problem is that with a 2.5 lift your up travel gets limited. I have high clearance fenders and have adjusted my bumps to get full stuff. If I had stock fenders then I would end up riding on the, or very close to the bumps all the time.
I assume you will have a 12.5 tire. with a 33 you could tuck it in a little more. Do you have fender laws?
If I started over I would go 2.5 lift and a 34x10.5 tire then after a year I would still upgrade to a 35. It would just be a dumb thing that I know I would do. I am 50 and still havn't learned about vehicles and money.
 

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Discussion Starter #5
Thanks guys. I like this forum - a little less activity than the general Wrangler forums, but the responses always seem genuine and well-considered. I appreciate it; thanks for welcoming me into the fold.

33's are basically the stock JK-sized tire. 35's fit very well and would match the 4.88 gears. With a JKU, you need a bigger tire. If I'm limited to those choices for a JKU going offroad, I will pick the 35's. I'll also recommend that you make sure you have a good belly skid.

Your axles should be perfectly fine, strength-wise to handle 35's with no reliability issues
I still have the 4.10 gears in a box and would be willing to spend the money to have them swapped back if the ride and reliability/longevity of suspension components is going to be noticeably better with 33's. I'm worried about all the extra maintenance and constant tweaking that might be needed when I go to 35's. (Now I need adjustable front UCAs to get the pinion angle right, need to replace the rear control arms with adjustable, etc. etc, etc,)

When you say "belly skid" are you talking about a skid plate that covers the entire undercarriage as opposed to individual skids for the various pieces? Can you point me to a good example that is popular?

The problem with 35's...
I have 2.5 lift and 35's and wouldn't go back to 33's. The only problem is that with a 2.5 lift your up travel gets limited. I have high clearance fenders and have adjusted my bumps to get full stuff. If I had stock fenders then I would end up riding on the, or very close to the bumps all the time.
I assume you will have a 12.5 tire. with a 33 you could tuck it in a little more. Do you have fender laws?
If I started over I would go 2.5 lift and a 34x10.5 tire then after a year I would still upgrade to a 35. It would just be a dumb thing that I know I would do. I am 50 and still havn't learned about vehicles and money.
All the time? As in riding down the street and pulling into driveways?:surprise: Or do you mean that you do so much extreme off road flexing that you would be on the bump stops "all the time" (while in heavier-duty scenarios off road)?

If I'm understanding you correctly, the thing I'd need to think about replacing if I go with 35's is the fender flares. Is the problem generally the outside lip making contact with the tire (because it extends outside the flare) and thus the need for "flat" fenders? Is there an option for a "wider" flare that will keep the mud from slinging all over the sides of the Jeep? (or are those all f'ugly?). I don't believe fender laws are really enforced here unless they really want to get you for something. Front license plates, however, are something people get routinely pulled over and ticketed for...

Just out of curiosity, why would you go with 34's first and then 35's?.

The crazy thing is that I'm sitting here with 2 complete sets of OEM Rubicon wheels, all of them with less than 2,000 miles on them. (5) JKUR with a full set of the OEM 32x9.5" BFG mud terrains and (5) JLUR along with three remaining OEM 33x11" BFG KO2s. But I've pretty much convinced myself that I don't want to run spacers, so i'm looking at new wheels (hopefully funded by selling all this stuff) and then either buy 2 new KO2s in 33x11" or try to sell those and go with 5 new 35x12.5's. My inner child of course wants the 35's but not if it is going to force me to always worry about issue with my suspension or lead me down a rat hole of constant tweaking to figure out why things are wobbling, scraping, grinding, etc...

I have a set of the Rock Krawler adjustable front UCAs in a box, so it would be just a matter of installing them and then finding a competent shop to set the pinion angle, right?

Sorry... so many questions. :)
 

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X4 on the 35's!

As for the gear question:
I'm running my TJ with a 5 speed stick and the 35's, with 4.88's and it is perfect around town and on the highway (65-75mph).

My gearing with the NV3550 is probably a little different that your JK. That being said, I would not pay good money for going back to the 4.10's. As you wrote, you're done with throwing money at vehicle problems, so don't do it! :)

On a side note, I have a lot of fun pulling away (for about 100 yards) from Beemers and Tesla's from a stop light. Once they figure out what is going on, they're gone but it is fun at least for a little while. lol

As for the other questions:
You've bitten off on quite a pickle. I would make a decision on 35's, then take one thing at a time as you discover how your rig responds to the 35's.
 

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Discussion Starter #8
Thanks again. So it looks like options in a 35x10.5 are limited (I prefer a skinny military look and less weight; I don't run deep sand dunes, so "flotation" from wide tires isn't really a decision criterion for me)

I just built a cart with 5 inexpensive (Mamba "M18") wheels and (5) KO2s in 34x10.5 and it was $2,700. Thats gonna be a tough one to sneak past the wife. 285/75's are a couple hundred less for 5, but they are load range E - not sure if that makes a difference...

OTH, I can get the wheels and a pair of 33" BFG KO2s to match the ones I destroyed for about $1,450. I figure I might be able to get $600-800 for the JKUR wheels + KM2s and probably about the same for just the JLUR wheels (I hope), which means I have $1,200-ish to play with. Perhaps I just live with that (and travel slowly on the highway) until I'm ready for the investment into 35's...

I guess I have to decide whether that extra inch is worth $1,300... (plus the $1,000 for flat fenders)

But I think the general consensus so far is "35's aren't going to be any more of an issue in terms of ride quality, handling, or reliability of suspension components than 33's would be..." (other than the fender issue pointed out by rlenglish, which is gonna cost an additional ~$1,000 to fix) . Am I right?

When I ran 4.88's & 33's on the CJ and 5.13's & 35's on the Scout I, I solved the freeway RPM problem with Warn Overdrives. That was a great solution. Does anyone make something like that for the JK 6-speed? >:)
 

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I've put about 50,000 miles on my JK with 35" tires, the first 12,000 miles were with stock suspension and flat fenders. I have had zero issues that I would blame on the size of the tires. Pinion angle will be affected by your lift not your tires. The bigger tires will move the axles and transfer case the same amount resulting in no change in angle. If the angle is currently correct and you have no drive shaft issues you won't need to change anything on that front. I don't remember if your lift came with upgraded steering components. If yes, don't worry about it, if no you might want to look into replacing the draglink, trackbar and tie rod with 35" tires. That's also something that you can wait and see to spread out the expense, but the heavier tires will wear down the components more quickly.


Do some googling on cutting the stock JK fenders. With a Dremel and steady hand you can have flat fenders for an hour or two's worth of work. I've seen some that were so well done they look like they could be aftermarket fenders.


When comparing the cost of 33s to 35sdon't forget to add in the cost of gearing back to 4.10. That won't be cheap either.
 

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I have the 34 X 10.50 X 17 BFG KO2's, I like the tires, but it was hard to find wheels with the proper offset that weren't too wide. Most of the wheels are designed for 11--12 inch wide tires. I think the ones that I got were 9 inches wide, they are a bit too wide for the tires IMHO. If I did it over again I would have run my stock Rubicon wheels with spacers to get the correct offset. I run SpyderTrax spacers on my LJ and have not had any problems. Just be sure they are hub and wheel centric. By the way, our 4-door has 3.73 gears, it hasn't been a problem so far, with the 5-speed automatic I just shift down a gear if I think the engine is lugging. Off-road you can control your low speed progress with left footed braking, so as to not lunge over rocks too fast.
 

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Discussion Starter #11
Thanks. I’m running 4.88’s in a 6-spd manual trans.

(Yea, I’m over 30 - when I say “trans” I mean “transmission”. Old habits die hard.)


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Yes JKs need 35s

After running 34s, (285/75-17) for 3 or 4 years and 45k I am switching to 35s which are marginally larger. In those 45k mles Ive had zero issues that would be tire size related from the stock 31/32 inch tires. The only thing I want is more gear, but you have that taken care of already.

If you have a lift existing and it is driving and behaving as it should now I wouldn't expect to see many problems related to tire size switch. If you don't already have one get a procal or something similar to adjust the engine/ trans parameters for the tire & gear combo.

Wheel choice and offset is key, taller wider tire needs more backspace to avoid problems, but not so much that the tires are way outside the fenders. The AEV back spacing on their wheels seems to work well with 35s I think its 4.625 off top of my head on a 8.5" wide wheel. Just remember that wheel width, tire width, back spacing and height are all related.

I too would love to find the elusive narrow 35/36 inch tire...super swamper makes em, but they are not appropriate for most uses.
 
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I too would like a narrow 35/36 tire. A 12.50 tire around here can be a hand full when changing lanes. The pavement grooves tend to pull you around.
I can be hitting the bump stops on most gravel roads. Your springs might be stiffer or your shocks can play a role also. If I had 33's then I could get another inch of up travel.
I think the important thing is to figure out where you are going to end up. Doing things twice is a pain. Heck I may end up on 40's. It just depends how bored a guy gets in the winter.
 

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Getting back to your question about the belly skid. The issue here is that the wheelbase on the JKU is so long, it has a more difficult time clearing rocks and other obstacles than a shorter wheelbase jeep on the same sized tires. Consequently the under carriage will pay the price with extra abuse.


Based on the plan you wrote for how you plan to use the jeep, you shouldn't need to put skid plates on immediately. Until you do armor up the bottom you'll need to pay attention to the lack of protection and drive over obstacles with extra caution. Still, for long-term piece of mind I recommend investing in armor. Even if you only planned to drive logging roads there will be rocks, logs, etc. that will try to bite the bottom of your jeep.


As far as specific suggestions, I leave that to others on the forum. As with many jeep products, you can buy piece-by-piece or all at once. Designs run the spectrum from Gucci (aluminum) to more simplistic with matching prices. If the aftermarket changes as it did when jeep went from the TJ to the JK, in the next few years, JK parts will become more and more difficult to find as the manufacturers concentrate on the JL/JT market. With that in mind, I'd recommend trying to buy sooner, rather than later.
 

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Discussion Starter #15
Getting back to your question about the belly skid. The issue here is that the wheelbase on the JKU is so long, it has a more difficult time clearing rocks and other obstacles than a shorter wheelbase jeep on the same sized tires. Consequently the under carriage will pay the price with extra abuse.

Based on the plan you wrote for how you plan to use the jeep, you shouldn't need to put skid plates on immediately. Until you do armor up the bottom you'll need to pay attention to the lack of protection and drive over obstacles with extra caution. Still, for long-term piece of mind I recommend investing in armor. Even if you only planned to drive logging roads there will be rocks, logs, etc. that will try to bite the bottom of your jeep.

As far as specific suggestions, I leave that to others on the forum. As with many jeep products, you can buy piece-by-piece or all at once. Designs run the spectrum from Gucci (aluminum) to more simplistic with matching prices. If the aftermarket changes as it did when jeep went from the TJ to the JK, in the next few years, JK parts will become more and more difficult to find as the manufacturers concentrate on the JL/JT market. With that in mind, I'd recommend trying to buy sooner, rather than later.
Thanks. About 20 years ago I switched from short wheelbase 4x4s to a 4x4 VW camper (that thing was a blast, btw) to double cab trucks (mostly to accommodate family) so I've gotten very used to dealing with a long wheelbase. The JKU feels like a nimble little cricket in comparison to my old F250! :D



I do plan to add some armor to the bottom - that evap box in particular looks very vulnerable. I just spent the afternoon yesterday re-routing some aux light wiring installed by the PO that was hanging inside the front fender well and under the frame to instead follow the stock loom down the pax side above the frame & gas tank for this same reason (I also added a 20 amp power feed to have aux power in the back). Boy, there is some close clearance between the pax side resonator and the rear bushing on the UCA - I would imagine that bushing needs to be replaced often if one spends a lot of at low speeds in hot weather...
 

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Discussion Starter #16
I too would like a narrow 35/36 tire. A 12.50 tire around here can be a hand full when changing lanes. The pavement grooves tend to pull you around.
I can be hitting the bump stops on most gravel roads. Your springs might be stiffer or your shocks can play a role also. If I had 33's then I could get another inch of up travel.
I think the important thing is to figure out where you are going to end up. Doing things twice is a pain. Heck I may end up on 40's. It just depends how bored a guy gets in the winter.
I think you guys have convinced me to go with 35s. Now I just need to figure out the wheel/tire combo. It looks like there are a couple of ways to get to a 35" tire. Looking at tire rack's web site it looks like the vast (and I mean VAST) majority of 5x5 17" wheels are 9" wide and offer a -12mm offset. According to them that will provide 4.5" backspace, but I'm not sure how they do that math.

I notice that AEV's wheels (a trusted name, to be sure) are all 8.5" and they claim 5.2" of backspacing and that 37" tires will fit with these wheels. However, Rock Crawler advises 4.5" backspacing for tires up to 35" and 3.5" backspacing for 37's and beyond.

I realize I am now drifting into a topic that has probably be covered 10,000 times already ("wheel and tire choice with xyz lift"), so if anyone has a link to a good and authoritative answer on this topic, I'd be grateful.

I want to avoid the mall crawler 'tires sticking out 4" past the fender' look
 
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....I want to avoid the mall crawler 'tires sticking out 4" past the fender' look
That is actually quite functional and not just to impress the mall crowd. Wider track mean more stability off-camber plus with minimal backspacing you won't have interference when making a tight turn (or not much interference.)
 

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Discussion Starter #18
Thanks John. Had a long (and great) conversation with Paul at AEV this AM about their wheels. They make an 8.5” (17) with 5.2” backspace and they say that it is the ideal geometry for 35-37” tires based on the concept of “scrub radius”. This keeps the wheels in tight but gives enough clearance for all the suspension components with a lift (2.5” to 4.5”). Sounds like a lot of thought went into their design for the JK.

I think I’m headed in that direction now... there’s a guy about 100 miles away from me selling a set of 5 AEV wheels and 315/70 BFG KO2’s with 10k miles on them for $1800. I might head down that path or buy new....


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The closer in your wheels the less stress on your axle and ball joints.
I have a 4.5 backspace and on turns (lock to lock) I have barely any clearance. If I went to a 5.2 BS then I would rub on the frame. I have not modified my steering stops.
Keep us informed.
 

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I think the AEV wheels are a good choice. I went with them because they were specific to the JK, designed with JK geometry and tire sizes in mind. An excellent value for what they are, JK specific wheels. I believe that extra design thought brings less wear and tear and better handling.
There are tons of wheel manufacture's but the back spacing and offsets are all compromises for the numerous applications that a 5x5 bolt pattern fits, not that most of them are bad they just are not vehicle specific.

Narrow tires and the wheels that fit them are just not popular, my ideal would probably be a 35/6 tire on a 7.5 or so wheel with 5 inches back space, no such animal unless I custom build a wheel and buy a container full of specially built tires...
 
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