35" to 37" considerations

[jadmt]

Since you have and use both 35's and 37's do you notice much difference off roading between the two?

I'm not sure I could definitely say one has any more "traction" then the other but I think the taller 37's just seem to crawl up and roll up and over things noticeably easier with less effort. Mine has 4.88's so in 4L it's super low which helps make slow crawling easier but I still think I notice a difference between the two sizes.

I don't really want anything wider then 12.50 on my JLUR but if someone made a 40 12.50 I sure wouldn't complain.

so I have been to Moab with 35x12.5-17 bb mt's, bb at's in 35" and bb at in 37's and the 37's absolutely make wheeling easier...you can be sloppier with your lines and roll over big ledges easier....I was keeping one set of 35's when I got my 37's and I literally flipped a coin between the mt and the at...the at won but would have been just as happy if the mt won...

I did moab rim a few months apart with both so both were still fresh in my mind and 37's made it much easier.

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[Cips]

so I have been to Moab with 35x12.5-17 bb mt's, bb at's in 35" and bb at in 37's and the 37's absolutely make wheeling easier...you can be sloppier with your lines and roll over big ledges easier....I was keeping one set of 35's when I got my 37's and I literally flipped a coin between the mt and the at...the at won but would have been just as happy if the mt won...

I did moab rim a few months apart with both so both were still fresh in my mind and 37's made it much easier.

Did you lose any significant 'uptravel' in your suspension because of the taller tire hitting anything sooner?

 

[yokramer]

Did you lose any significant 'uptravel' in your suspension because of the taller tire hitting anything sooner?

Yea however much sooner you touch and the tire stops, or whatever bumpstop you add to keep it from touching. Unless you just let it hit the plastic and let it self clearance then you dont really lose anything.

 

[jadmt]

Did you lose any significant 'uptravel' in your suspension because of the taller tire hitting anything sooner?

no on my AEV 2.5 the bump stops stop the up travel before the tire makes contact with the fender.it is close but never rubbed once on Steel bender or Moab rim or flat iron mesa etc.. the AEV wheeloffset helps as well. know thephoto looks like it might be touching but it is not and the bumps are preventing any further travel.

 

[rickinAZ]

That's some good info. I do have a FlashPaq from SuperChips. Among a host of other settings, it does allow for tire and wheel size input. The tire size can get very specific, down to a 1/4". It also makes changes to the transmission shifting points as well. Now whether or not the transmission flash factors in tire/wheel size, I do not know.

I found that actually "measuring" the tire isn't as accurate as using your GPS to calibrate versus the speedo. Then use the tire size input on your Flashpaq to finetune it until they speedo/GPS match perfectly. I found that my tape measure provided a number that was .5" off.

 

[WXman]

I'm getting ready to buy tires for mine, not because I need them but just because I want them. I'm having a really hard time deciding between 35 and 37 myself. I've had 35s in the past on my Jeeps and was surprised at how civil they felt on the road. So thinking of upgrading a little more this time around. But I just don't know. I will be towing with the Jeep some, and commuting in it quite a bit. Off-road use will be occasional.

 

[jadmt]

fuggg i need 38's....guy just ask me if my jeep had 35's..........he was serious....

 

[2nd 392]

fuggg i need 38's....guy just ask me if my jeep had 35's..........he was serious....

I feel your pain .. 32 uhh 5’s

 

[scorpionsix]

One of the things I also have to factor in is buying 4 vs 5 new tires. I have a new 35" spare that is going to stay a spare if I do not go with 37s. The previous owner did not do 5 tire rotations and now the tread depth gap is just such that I'm not going to press it into service. I was considering aftermarket wheels as well but I would rather not off-road with custom wheels so sticking with just tires would keep the upgrade at just tires and a beefed up spare tire carrier.

 

[WXman]

One of the things I also have to factor in is buying 4 vs 5 new tires. I have a new 35" spare that is going to stay a spare if I do not go with 37s. The previous owner did not do 5 tire rotations and now the tread depth gap is just such that I'm not going to press it into service. I was considering aftermarket wheels as well but I would rather not off-road with custom wheels so sticking with just tires would keep the upgrade at just tires and a beefed up spare tire carrier.

Yep that's a big deal. Putting a 37 on the OE tire carrier is probably a bad idea. I have seen that a 35 will fit, but it's SNUG. In the past when I ran 35s I'd keep the 33" factory spare and just use a tire cover. My reasoning was that in my 31 years of driving I've only had two flat tires, and in the event that I really do need an emergency spare I can throw the 33" on, drop the pressure in the remaining three 35s down enough that the diameters are close at all four corners, and carefully drive back to the trailhead or to the nearest tire shop. But, playing those odds and not buying a 5th wheel/tire saves me $600.

 

[scorpionsix]

Yep that's a big deal. Putting a 37 on the OE tire carrier is probably a bad idea. I have seen that a 35 will fit, but it's SNUG. In the past when I ran 35s I'd keep the 33" factory spare and just use a tire cover. My reasoning was that in my 31 years of driving I've only had two flat tires, and in the event that I really do need an emergency spare I can throw the 33" on, drop the pressure in the remaining three 35s down enough that the diameters are close at all four corners, and carefully drive back to the trailhead or to the nearest tire shop. But, playing those odds and not buying a 5th wheel/tire saves me $600.

And then there's the omnipresent argument for regearing. I do have the 2.0L and it doesn't get driven like Miss Daisy. Regearing would no doubt "protect" the engine and allow me to continue to surprise people at stoplights. Reminds me of a time I was returning an empty U-Haul. Sitting at a stoplight, I watched a few cars switch lanes because they assumed I was going to be slow. When my second favorite shade of green appeared, I pulled a John Force and smiled the rest of the way to the store.

 

[yokramer]

One of the things I also have to factor in is buying 4 vs 5 new tires. I have a new 35" spare that is going to stay a spare if I do not go with 37s. The previous owner did not do 5 tire rotations and now the tread depth gap is just such that I'm not going to press it into service. I was considering aftermarket wheels as well but I would rather not off-road with custom wheels so sticking with just tires would keep the upgrade at just tires and a beefed up spare tire carrier.

The whole point of getting an aftermarket wheel is so you can run better/bigger tires, better offset, and if you go bead grip/whatever the icon thing is you can more reliably go lower air pressure. Why would you NOT off road with them?

 

[zouch]

i think you know the right answer, but just don't want to accept it yet; we all understand. tire lust is a strong force.

i'd make sure you have a tire carrier that will get a 37 out of the bumper before making that jump. some rubis stock rear bumpers will not clear a 37 with the stock carrier.

for now, get a set of good 35s and get your rig and your wallet ready for the 37s you really want. (i'd say get 5; throw away that aged spare you don't want to use, or if you think it's good enough for use, buy 4 more to match and rotate it through when the tread depth matches; that'll help to get the most value out of it.)
do your spare carrier upgrade while you wear out your 35s, and have a few $K ready for regearing when (not 'if') you decide you want it.

wheels only if you decide you need a different look, or are moving to beadlock/bead grips for off-pavé work.

FWIW, 37s rubbed in the normal place on the rear lower edge of my rear inner fender liners to the point they wore through; i wasn't willing to limit flex by using bump stops as i like a low (2-3") lift.
37s also rub the outer edge of my Antirock arms, but that's acceptable (to me) as it's only a little bit at full lock and could be minimized by spacing out the steering stops a bit. there is no rubbing on Control Arms, but i'm not using the stock arms.

The 2020 JLUR I purchased last summer came with BFG KO2s 35x12.5x17 riding on a 3" lift. They are wearing down and later this year will need replaced. I am considering going with Mickey Thompson Baja Boss EXPs in a 37x12.5.17. The weight difference is only 2lbs per tire. I would be going from an E rated to a C rated tire. Weight being very similar, the drive train being 4.10 & 4.10 and the engine being the 2.0L (tuned) what other aspects of this larger tire upgrade should I consider?

One of the things I also have to factor in is buying 4 vs 5 new tires. I have a new 35" spare that is going to stay a spare if I do not go with 37s. The previous owner did not do 5 tire rotations and now the tread depth gap is just such that I'm not going to press it into service. I was considering aftermarket wheels as well but I would rather not off-road with custom wheels so sticking with just tires would keep the upgrade at just tires and a beefed up spare tire carrier.

 

[stretch-bsn]

Went from 315’s falkin wildpeaks E rated to 37” KO2’s C rated. Axles geared at 3.73. It was a 9lbs drop in weight around each corner.

I’ve run it on road most but definitely wheeled it and it’s great. I love it.

 

[scorpionsix]

The motorcycle bug is biting again and that is no doubt going to impact the final decision on new tire size, wheels and regearing.

Went from 315’s falkin wildpeaks E rated to 37” KO2’s C rated. Axles geared at 3.73. It was a 9lbs drop in weight around each corner.

I’ve run it on road most but definitely wheeled it and it’s great. I love it.

I spent some time in NoVA/DMV. Have a Face Plant (Lost Rhino) or two for me.

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