37 on sport s without lift

[Geekjeep]

So. Getting the itch for 37s. Problem is I don’t want to lift. I known 35s can be fit with no problem. Can 37s fit with just rim offset? Also has anyone put 37 with the 3.73 gears? It’s what a 250 rpm difference over the 4.10. Can’t imagine it’s noticeable 3.73 vs 4.10

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[Geekjeep]

I’ve done a ton of reading but still can’t find someone who’s put 37s without lift. Please help. Ready to pull the trigger

 

[XJ2JTChris]

Where are you reading this garbage? I have a Sport S with the 4.10's. I went with 35's so I can still have SOME sort of towing and hauling performance. It is DEFINITELY noticeable, so I can only imagine how much worse a 37 is, let alone a 37 with 3:73's. But then again, i've been building cars and trucks for over 10 years so i'm a bit more sensitive to performance loss and gains. Maybe all the searches are yielding results from people that really don't have a clue, even when behind the wheel first hand. Good luck with whatever you decide, you can always sell what you purchase if you don't like it!

 

[Geekjeep]

I think I didn’tnget my point across. My bad dude. I meant I’ve seen a lot of rubicons with 37 which have 4.10 gears. I’m sharing that 4.10 vs 3.73 shouldn’t a noticeable difference. I think the math is 250 rpm or so between those.
Agreed stock vs 37 tire will be a big difference. I’m on 35 now and am very happy with the performance. The 37s aren’t much heavier. So I’m just trying to get some feedback on running 37 with 3.73 with no lift/minimal lift.

 

[XJ2JTChris]

I gotcha, do you wheel at all? I can't say for sure on 37's, but my 35's were very close to rubbing during full flex on a recent off road trip I was on. And that's including 1.5" coil spacer up front and .75 in rear. It was the front that came very close to rubbing on the fender flares. Stock non-rubicon I think you'll have a clearance issue during articulation. Just an assumption. Hopefully you find some replies from first hand folks. Good luck!

 

[Geekjeep]

I do a host of activities from extreme mall crawling to driving down flat roads lol. I have another Jeep to beat on. This is still way too nice to beat on. I’ll keep up the search. But I guess it would be somewhat safe to assume that the power or loss of power would be similar to 4.10?

 

[Renegade]

You see this guy’s posts about running 37s without a lift? I haven’t read anything from him in quite a while...
https://www.jeepgladiatorforum.com/forum/threads/37s-on-my-stock-height-jt-sport.18259/

 

[PyrPatriot]

Where are you reading this garbage? I have a Sport S with the 4.10's. I went with 35's so I can still have SOME sort of towing and hauling performance. It is DEFINITELY noticeable, so I can only imagine how much worse a 37 i

My performance to 35s took a big hit. Then again, from OEM tires to 32 mud terrains took a big hit. Went from 19-21mpg, to 18mpg on the 32" Falken M/T (yes 255/75/17 not Rubicon takeoffs), and now down to 15mpg on the 35 versions. The 37s only weigh a couple pounds more than the 35s, and frankly going to 37" geolandar m/ts would be less weight than my 35s! So performance loss depends on the weight of the setup. My 35s on stock rims are only 7lbs per corner heavier than a Rubicon OEM tire on a steel wheel, 17lbs if on alloy wheels, but man does it make a difference.

I gotcha, do you wheel at all? I can't say for sure on 37's, but my 35's were very close to rubbing during full flex on a recent off road trip I was on. And that's including 1.5" coil spacer up front and .75 in rear.

I rub on full articulation but the trails I go on that is rare. JTs have A LOT of articulation capability even with sway bar connected. No spacers as a leveling kit or on the wheels. I'm betting once I get on the Rubicon fender flares there will be the same "close to rubbing" I have now on trails with 37s

 

[Jeeperjamie]

I'm running 35's on my Max tow with 4.10 gears and I haven't saw much of a hit in performance. I took about a 3 mpg hit as far as gas mileage goes, went from close to 21 to just over 18 MPGs. With that said a friend of mine has 35's on his Sport S non Max tow with 35's and 3.73 gears and he's getting around 14.5 MPGs, pretty much the same driving habits. His does ok but you can definitely tell a difference between driving mine and driving his. On 37's he would have a slug and I'm pretty sure there would be fitment issues especially at full turn because you also don't have the wider axles, like a Rubicon and Max Tow have. If it was me I wouldn't even entertain putting 37's on one with 3.73 gears even lifted. Just my 2 cents.

 

[Jeeperjamie]

Here is your answer. Your definitely going to rub unless you put some after market wheels on or spacers. He's pretty close on a Rubi, plus he has the higher fenders and sits about a inch taller stock than a Regular sport s. Your going to have clearance and rubbing issues on 37's.

 

[Blknblu]

37's will fit, just don't plan on turning or going over speed bumps. 35's rub on the fender extension to the bumper too.

Bruce

 

[Alabama Mud Machine]

I think I didn’tnget my point across. My bad dude. I meant I’ve seen a lot of rubicons with 37 which have 4.10 gears. I’m sharing that 4.10 vs 3.73 shouldn’t a noticeable difference. I think the math is 250 rpm or so between those.
Agreed stock vs 37 tire will be a big difference. I’m on 35 now and am very happy with the performance. The 37s aren’t much heavier. So I’m just trying to get some feedback on running 37 with 3.73 with no lift/minimal lift.

It’s not so much about the RPM numbers themselves, as it is about how well you keep the drivetrain happy by staying in its useable power band. There will be a noticeable difference in 3.73 vs. 4.10 gears and 37’s with as underpowered as the JT’s are. If they had the Hemi V8 with a very broad power curve, that would be one thing, but a small 285 BHP V6 is going to be a noticeable drop in performance with nearly a half a revolution difference in gearing.

Theres a reason most guys with factory 4.10’s go to 4.88’s with 37’s.

 

[PyrPatriot]

It’s not so much about the RPM numbers themselves, as it is about how well you keep the drivetrain happy by staying in its useable power band. There will be a noticeable difference in 3.73 vs. 4.10 gears and 37’s with as underpowered as the JT’s are. If they had the Hemi V8 with a very broad power curve, that would be one thing, but a small 285 BHP V6 is going to be a noticeable drop in performance with nearly a half a revolution difference in gearing.

Theres a reason most guys with factory 4.10’s go to 4.88’s with 37’s.

But if the weight between 35s and 37s is only a few pounds per tire, where is the greater strain coming from? My 35" falkens weigh 7lbs more per wheel/tire combo than the 33" falkens on steel oem wheels (an option you can order at the dealer). So it seems like the JT with 4.10 can handle the extra load.

OEM Rubicon Alloy Wheels: 23lbs (post 15 in this thread)
Falken Wildpeak M/Ts LT285/75/17 - 61.3lbs each (63.9lbs in said reference thread as on the scale but if those were the A/Ts those are stated to weigh 62.8lbs for the C load and 58.9 for the D load)
Falken Wildpeak M/Ts 35x12.5x17 - 79.6lbs each
Falken Wildpeak M/Ts 37x12.5x17 - 81.8lbs each

So stock Rubicon puts you at about 86lbs at each corner. 96lbs if on steel wheels.
35s put you at 103lbs at each corner. That is 17lbs more than factory, 7lbs more if you got the steel rims
37s put you at 105lbs at each corner, an increase of 9/19lbs depending on rim.

What am I missing?

 

[Alabama Mud Machine]

But if the weight between 35s and 37s is only a few pounds per tire, where is the greater strain coming from? My 35" falkens weigh 7lbs more per wheel/tire combo than the 33" falkens on steel oem wheels (an option you can order at the dealer). So it seems like the JT with 4.10 can handle the extra load.

OEM Rubicon Alloy Wheels: 23lbs (post 15 in this thread)
Falken Wildpeak M/Ts LT285/75/17 - 61.3lbs each (63.9lbs in said reference thread as on the scale but if those were the A/Ts those are stated to weigh 62.8lbs for the C load and 58.9 for the D load)
Falken Wildpeak M/Ts 35x12.5x17 - 79.6lbs each
Falken Wildpeak M/Ts 37x12.5x17 - 81.8lbs each

So stock Rubicon puts you at about 86lbs at each corner. 96lbs if on steel wheels.
35s put you at 103lbs at each corner. That is 17lbs more than factory, 7lbs more if you got the steel rims
37s put you at 105lbs at each corner, an increase of 9/19lbs depending on rim.

What am I missing?

It’s not all about weight. Weight has more to do with rotational mass and fuel mileage, but tire & wheel weight does affect overall performance of the engine and if underpowered it can really lug it down. But re-gearing is mostly about tire height. Taller tires travel less revolutions per mile, which is why you match gear ratios to your tire sizes to make up for that with taller gears, to recorrect the final gearing of your drivetrain. There is SOME leeway, but not that much. Which is why if you don’t correct your ECM and TCM for tire size, it throws everything out of whack. Which is why recalibration is so vital.

 

[jrb517]

But if the weight between 35s and 37s is only a few pounds per tire, where is the greater strain coming from? My 35" falkens weigh 7lbs more per wheel/tire combo than the 33" falkens on steel oem wheels (an option you can order at the dealer). So it seems like the JT with 4.10 can handle the extra load.

OEM Rubicon Alloy Wheels: 23lbs (post 15 in this thread)
Falken Wildpeak M/Ts LT285/75/17 - 61.3lbs each (63.9lbs in said reference thread as on the scale but if those were the A/Ts those are stated to weigh 62.8lbs for the C load and 58.9 for the D load)
Falken Wildpeak M/Ts 35x12.5x17 - 79.6lbs each
Falken Wildpeak M/Ts 37x12.5x17 - 81.8lbs each

So stock Rubicon puts you at about 86lbs at each corner. 96lbs if on steel wheels.
35s put you at 103lbs at each corner. That is 17lbs more than factory, 7lbs more if you got the steel rims
37s put you at 105lbs at each corner, an increase of 9/19lbs depending on rim.

What am I missing?

I'm no mechanical engineer, but I believe the issue isn't with the weight of the setup necessarily, but with the added stress you put on the drivetrain by running lower gear ratios.

https://www.fourwheeler.com/how-to/1211or-why-change-gear-ratios/

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