JL/JT’s on 40’s

RCC

Active Member
I’ve got question for you guys/gals who run 40’s on your JL/JT’s and use a taser.

Is there a relearn process with the trans? My JT seems to really like cruising in 6th gear at 65mph and 3,000 rpms. It will eventually shift to 7th but it seems to hang in 6th for a good while.

My taser is set to 39.5“ tires and 5.38 gears. Is this normal?
 
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OverlanderJK

Resident Smartass
So it’s normal?

I figured it was slightly over geared with 5.38’s but I guess I need to up my math skills.
I know my JK was different but 5.38’s and 40’s was third gear all day. Needs more gearing in my opinion. Somewhere around 6.00 but nobody makes anything like that.
 

RCC

Active Member
This the math I used to figure 5.38’s with 40’s is lowered geared than 4.10’s and 33’s.

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MericaMade

Active Member
As far as tire size on the Tazer I notice you need to run a small number then tire size you have. For my JK not JL I set Jscan to 39.25 on tires and 5.38s and at 80mph I am at 3k rpm.
 

Ddays

Hooked
Regearing and resetting with the Tazer doesn't make the 40" tires and wheels weigh less. Tha'ts a lot of extra rotational mass to keep moving
 
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WJCO

Meme King
No 40s here, but for the speedo, I found the Tazer to work damn near perfectly setting it to what the tire manufacturer says on their website for diameter. I messed around with it lower and higher but found the tire manufacturer's printed info on the website was perfect. Did this with two different manufacturers. Not sure if that would affect the rpms and shifting though.
 
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