Another 37 vs 40 thread

Which LS3? 5.3?, 6.0? Or 6.2? 40s, including a spare, along with heavier wheels and the heavier axles will rob a bit of power from the V8. Much of that due to shear rolling resistance. You can feel the difference between 37s and 40s. Assume you’re at relatively low altitude as that can rob even more of that V8 “snappiness”. If you like to whip around and do burnouts the 37s will be more fun. If you like rolling over a lot of stuff while wheeling you’ll like the 40s.


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jdofmemi said:
That would be like going back to stock, except nearly unbreakable.

Sounds like a good challenge to pick your lines.
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Less clearance.


Basscat said:
Which LS3? 5.3?, 6.0? Or 6.2? 40s, including a spare, along with heavier wheels and the heavier axles will rob a bit of power from the V8. Much of that due to shear rolling resistance. You can feel the difference between 37s and 40s. Assume you’re at relatively low altitude as that can rob even more of that V8 “snappiness”. If you like to whip around and do burnouts the 37s will be more fun. If you like rolling over a lot of stuff while wheeling you’ll like the 40s.


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LS3 is a 6.2. 40s are liveable with a 3.6 Pentastar. With more than double the power, it’s plenty fine.


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You just pick the harder lines...all the time. Then you start thinking you can defy gravity, then do something stupid...
 
nothing wrong with rolling 37s. eddie ran 37s on one of his rides for a long, long time. is this daily driven? me personally. i've got short legs. i am on 35s right now and will eventually go to 37s. but, i wouldn't want to have to get in and out of 40s if i was daily driving.
 
To answer a few questions. The LS is actually a L94 which is a truck motor similar in specs to the LS3. 6.2L with 408HP w/o modifications. Another thing to note is that I would be going from 37” Nittos that weigh 86 lbs each to 40” Coopers that weight 92 lbs each. 6lbs per corner shouldn’t be as drastic as if I were going from 37” Nittos to 40” Nittos (almost a 20lb jump).

This is not a daily driver and I’m 6’ 2” so not worried about getting in and out. The question about where and who I wheel with is a great question. I’m Oregon and mostly wheeling in the Tillamook State Forest but we do annual trips to Rubicon, Moab, etc. Most of the guys are on 37’s but most have also talked about jumping to 40’s. I’d love to have 40’s for the Rubicon but i have heard a few people say they prefer Moab on 37’s.
 
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SLO said:
To answer a few questions. The LS is actually a L94 which is a truck motor similar in specs to the LS3. 6.2L with 408HP w/o modifications. Another thing to note is that I would be going from 37” Nittos that weigh 86 lbs each to 40” Coopers that weight 92 lbs each. 6lbs per corner shouldn’t be as drastic as if I were going from 37” Nittos to 40” Nittos (almost a 20lb jump).

This is not a daily driver and I’m 6’ 2” so not worried about getting in and out. The question about where and who I wheel with is a great question. I’m Oregon and mostly wheeling in the Tillamook State Forest but we do annual trips to Rubicon, Moab, etc. Most of the guys are on 37’s but most have also talked about jumping to 40’s. I’d love to have 40’s for the Rubicon but i have heard a few people say they prefer Moab on 37’s.
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this is easy in your situation. go 40s and don't look back.
 
Most folks who think about 40s and have 37s won’t stop contemplating until they have 40s. Then they either stay with them or go smaller again. You won’t shake that bug until you go 40s. Then you’ll know for sure.


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Basscat said:
Most folks who think about 40s and have 37s won’t stop contemplating until they have 40s. Then they either stay with them or go smaller again. You won’t shake that bug until you go 40s. Then you’ll know for sure.


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Solid advise! I think you pretty much nailed it. Maybe I’ll hold off on selling the 37’s for a bit.


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Hello all. I just picked up my JKU from Motech. I had an L99 crate engine put in along with a crate 6L80 transmission and a new Atlas transfer case. I am running 40'S on Currie RockJock VXR 60's and it drives great!!! +++ a lot more. Robbie at Motech is the way to go.
 
Rocralr said:
Hello all. I just picked up my JKU from Motech. I had an L99 crate engine put in along with a crate 6L80 transmission and a new Atlas transfer case. I am running 40'S on Currie RockJock VXR 60's and it drives great!!! +++ a lot more. Robbie at Motech is the way to go.
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CA emissions legal?


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fiend said:
Possible. L99 is the Camaro engine, so you’d meet the GVWR limitation.


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The classifications between car and truck are beyond stupid considering the block and head is the same. Robbie is pretty careful about what he does in regards to compliance so I’m sure it’ll meet emissions.

I personally don’t offer the car engines because they’re more expensive and there isn’t any power gain.


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Rocralr said:
Hello all. I just picked up my JKU from Motech. I had an L99 crate engine put in along with a crate 6L80 transmission and a new Atlas transfer case. I am running 40'S on Currie RockJock VXR 60's and it drives great!!! +++ a lot more. Robbie at Motech is the way to go.
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How much does that cost? $20k? I want a V8 someday.
 
Rocralr said:
Hello all. I just picked up my JKU from Motech. I had an L99 crate engine put in along with a crate 6L80 transmission and a new Atlas transfer case. I am running 40'S on Currie RockJock VXR 60's and it drives great!!! +++ a lot more. Robbie at Motech is the way to go.
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When did you drop it off? Curious if mine is close. What color is yours? I’m sure I saw it there when I dropped mine off?


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