PR 60/Pro 60 Combo Gearing Question.

LO_Rex

LO_Rex

New member
I am in the process of ordering the hardcore 60 axle combo and I am on the fence between 5.38 and 5.13 gearing.

My JKUR is a 3.6L manual and my plan is to go with 37" tires to start. It is not my only daily driver but is driven on the road. The gear charts show like 150RPM differance between the two.

Anyone have real world feedback on the performace diffrence between the two?



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WJCO

WJCO

Meme King
I'll bet Eddie could answer that. I believe Moby is running a similar setup. 6.2L Manual with D60 front and D80 rear.
 
jesse3638

jesse3638

Hooked
Motech had a lot of info on gear combos. They consider trans and t-case as well in determining what the gears should be. One combo was running 488's on 40's if I remember correctly.
 
LO_Rex

LO_Rex

New member
jesse3638 said:
Motech had a lot of info on gear combos. They consider trans and t-case as well in determining what the gears should be. One combo was running 488's on 40's if I remember correctly.
Click to expand...
Sorry my mistake I should have wrote 3.6L Pentastar in my intial post.

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SDG

SDG

Caught the Bug
5.38 is what I would do if you ever want to go bigger tires, it will still be fine on 37's, but a little higher in the rpm range. You get 513 and 40s would be a dog always, since it isnt primary vehicle i would still do 5.38. Irishjk ran 5.38 with 3.6 auto for a while while he waited for 40s off backorder. Maybe he will chime in.

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tgoss

tgoss

New member
jesse3638 said:
Motech had a lot of info on gear combos. They consider trans and t-case as well in determining what the gears should be. One combo was running 488's on 40's if I remember correctly.
Click to expand...

Robbie recommended 4.56 for mine. (40's, LS3, 6L80, Atlas 2).
 
J

JKDream

Guest
LO_Rex said:
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Click to expand...
Personally I would go 5:13. I run them now on 37s and to me - it feels like too much gear. My RPMs are a bit higher on the highway than I would like. Adding 40s would be more tolerable. Had I do it over again sticking with 37s I would have gone 4:88.
 
wayoflife

wayoflife

Administrator
Staff member
LO_Rex said:
I am in the process of ordering the hardcore 60 axle combo and I am on the fence between 5.38 and 5.13 gearing.

My JKUR is a 3.6L manual and my plan is to go with 37" tires to start. It is not my only daily driver but is driven on the road. The gear charts show like 150RPM differance between the two.

Anyone have real world feedback on the performace diffrence between the two?



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Click to expand...

As mentioned, if you think there's a chance you'll run 40's someday, I would go 5.38. Otherwise, 5.13 is a better ratio for 37s. 5.13s is what I used to run but bumped up to 5.38 in anticipation of going 40 but really don't like it with 37.


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Basscat

Basscat

Member
LO_Rex said:
I am in the process of ordering the hardcore 60 axle combo and I am on the fence between 5.38 and 5.13 gearing.

My JKUR is a 3.6L manual and my plan is to go with 37" tires to start. It is not my only daily driver but is driven on the road. The gear charts show like 150RPM differance between the two.

Anyone have real world feedback on the performace diffrence between the two?



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Click to expand...

I've run both tire sizes but not your exact engine / transmission combo which really is the key to this thing. That said I'd recommend 5.13s for 37" and 5.38s for 40". You can maybe cheat taller or deeper depending on altitude and terrain ( mountainous vs flat).


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LO_Rex

LO_Rex

New member
Thanks for the advice everyone. I think 5.13 is my best choice for my 37" setup. 40s wont be coming for a long time.

I will be installing EVO coilovers with my axles and my understaning is that they are not suited well for the weight of 40s.

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aermotor

aermotor

Member
I'm sure there are at least hundreds if not thousands of JKs that run King coilovers on 40s...

I don't really know about sprung vs unsprung weight but would imagine 40s should not have as much of a direct effect on coilovers.
 
Basscat

Basscat

Member
LO_Rex said:
Thanks for the advice everyone. I think 5.13 is my best choice for my 37" setup. 40s wont be coming for a long time.

I will be installing EVO coilovers with my axles and my understaning is that they are not suited well for the weight of 40s.

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Click to expand...

As for the EVO coil overs and 40s that really depends on what you do with the Jeep. If the intent is high speed desert racing or running fast off road and you've got your 40s paired with big axles assemblies then yes you'll need the extra dampening of a larger shock (2.5 or 3.0) which is harder to make work but not impossible on a JKU so hence the triple bypass shocks that come with the Double Throw Down set up. BUT if that's not in the cards and you're primarily talking about running trails and/or crawling the EVO coil overs will work just fine both on and off road with 40s. It's amazing how well they can be tuned (shim stacks and spring rates) to suit your needs. Even more amazing is how close EVO gets right out of the box for the average JKU (6k lbs total / 4K to 4.5k sprung) with their tuning. Coil overs will work.


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Irish JK

Irish JK

Caught the Bug
SDG said:
5.38 is what I would do if you ever want to go bigger tires, it will still be fine on 37's, but a little higher in the rpm range. You get 513 and 40s would be a dog always, since it isnt primary vehicle i would still do 5.38. Irishjk ran 5.38 with 3.6 auto for a while while he waited for 40s off backorder. Maybe he will chime in.

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Click to expand...

As others have said. 5.38s with 37s is completely fine, even with an 80 rear. I wasn't particularly fond of the rpm needed for freeway speed but with that being said if there's even a slight chance of going to 40s, go 5.38, you don't want to be regearing those if you don't have to be.

As for Evo's bolt on coilovers, there is no reason you can't run with 40s and makes for an awesome crawling setup. Just remember like any shock, they do eventually wear, but with a quality one like King, you rebuild them and can make slight tuning adjustments at that time to fit your needs.
 
jorgelrod

jorgelrod

Hooked
aermotor said:
I'm sure there are at least hundreds if not thousands of JKs that run King coilovers on 40s...

I don't really know about sprung vs unsprung weight but would imagine 40s should not have as much of a direct effect on coilovers.
Click to expand...

“Unsprung weight” moves when the wheel moves. “Sprung weight” moves when the chassis moves.
Weight controlled by the suspension, and usually below the suspension, which forces it into contact with the road surface or other components, is unsprung weight.
Weight supported by the suspension, and usually above the suspension, which separates and isolates it from the road surface and other components, is sprung weight.
 
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