Gears for 37" tires

[hjdca]

Question for the gearing group. If one has plans to do a supercharger at a later date, is it wiser to wait and do that first and then re-gear, to re-gear first then blower, or it doesn't really matter? I'm also at elevation out in CO.

I have gone through both processes. If you are lacking on power, my advice would be to get the 5:13 gears first, then, reassess if you really need a supercharger. You will be super impressed with the torque with the 5:13 gears.

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[StingyJT]

75mph on 5.13s on 37” Cooper ST Maxx. I don’t think 80mph would too busy.

 

[Tufelhundin]

@mellendic and @AZCooWhip, @StingyJT thats incredible!!!

You can see my signature with what I’m running in flatland Louisiana.

The picture is no wind and flat road with cruise. This is why I can't see decent mileage... it won’t get it.

I swear some JT’s do extremely well and others are like mine. Very disappointing

 

[j.o.y.ride]

ugh. now maybe I will do 5.13s. It'll be spinny on the 35s until I do 37s.

 

[mellendic]

I have gone through both processes. If you are lacking on power, my advice would be to get the 5:13 gears first, then, reassess if you really need a supercharger. You will be super impressed with the torque with the 5:13 gears.

My next jump is a supercharger, but this —-^ is totally correct

 

[mellendic]

Question for the gearing group. If one has plans to do a supercharger at a later date, is it wiser to wait and do that first and then re-gear, to re-gear first then blower, or it doesn't really matter? I'm also at elevation out in CO.

Someone that is smarter than me should chime in. But gears have to do with rotational physics and resetting the rotational physics to normal so the engine can work as designed. So a supercharger will just give more power to what is the changed baseline.

 

[EstoJTR]

Understood, however now I'm wondering if I should still only go up in equivalency to factory (i.e. 4.88's for 37's) if I plan to supercharger. I'm still on 35's right now but will be going to 37's once I lift hopefully later this year. I'm just enjoying the step by step money sink at this point . I'd love to move up my timelines, but got to put the money elsewhere for now .

 

[duvinclunk]

Quite interesting opinions at the beginning of this thread. just bought a 21 Rubicon and it will be seeing new gears before 100 miles on the odo.

 

[Jeeperjamie]

4.10 gears and I'm dead on at 72mph and averaging 17.2 mpg, had it almost to 18 a few times. I have 2 5" Readylift installed with Rubicon take-offs on a Max Tow, got almost 3,000 miles on it since putting the 37's on. My shift points are pretty much spot on and it doesn't feel likes it's dragging and it gets up to speed great as well. I normally stay around 70-75 mph on the interstate, my driving is a 60/40 mix of city/hwy.

 

[Jlmckinney]

ugh. now maybe I will do 5.13s. It'll be spinny on the 35s until I do 37s.

I’m right there with ya, I know I’ll be doing 37s after I lift , may as well do it right the first time

 

[iGlad]

ugh. now maybe I will do 5.13s. It'll be spinny on the 35s until I do 37s.

What do you mean by spinny?

 

[j.o.y.ride]

What do you mean by spinny?

Higher rpms than wanted at high speeds

 

[Silvertruck]

4.10 gears and I'm dead on at 72mph and averaging 17.2 mpg, had it almost to 18 a few times. I have 2 5" Readylift installed with Rubicon take-offs on a Max Tow, got almost 3,000 miles on it since putting the 37's on. My shift points are pretty much spot on and it doesn't feel likes it's dragging and it gets up to speed great as well. I normally stay around 70-75 mph on the interstate, my driving is a 60/40 mix of city/hwy.

Yes, but you are in 7th not 8th.

 

[Jeeperjamie]

Yes, but you are in 7th not 8th.

True, but I'm also going up hill in that picture.

 

[duvinclunk]

Does anyone getting a high pitched hum coming from the transfer case with 5.13s? We originally thought it was the gear installation but we've gone back twice now and that's spot on. I'm the only one that can notice it but was told that it is likely to do with the driveline spinning much faster than before. I test drove 2 other 5.13 JTs this weekend and they had the same hum. What is it?

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