Bigger tires and power questions -
LinkBack Thread Tools
post #1 of 5 Old 01-15-2020, 02:00 PM Thread Starter
Registered User
Join Date: May 2007
Location: New York
Posts: 39
Bigger tires and power questions

On a rubicon, going to run 38x13.5 tires. With the stock 4.10s will it have a decent amount of power. Should I change the gearing. I had a 2017 with 37's and changed to 5.13. Jeep ran nice not to powerful, i guess almost the same as stock. Do the JL's have alittle more power "feel". I was going to do a magnuson supercharger but worried about warranty.

JSG1518 is offline  
Sponsored Links
post #2 of 5 Old 01-23-2020, 02:29 AM
Registered User
Prot's Avatar
2014 JK Wrangler 
Join Date: Feb 2007
Location: Lafayette
Posts: 8,624
Automatic or manual transmission? I assume you have the V6.

2014 JKU Copperhead Pearl
Too many mods to list. Too awesome to sell.
Prot is offline  
post #3 of 5 Old 01-23-2020, 07:56 AM
Registered User
JIMBOX's Avatar
2018 LJ Wrangler 
Join Date: Oct 2008
Posts: 7,628
If you're "going to run" 38"s without changing gearing---doesn't matter if you have a stick ot auto---

You're going to have a "DEAD DOG"--

You've done this before with ALMOST THE SAME ENGINE--

You could run all day in 4lo-



Firecracker Red 2dr RUBICON--2018
Stinger Yellow 2016 RAM/Hemi/8spd auto 4x4

JIMBOX is offline  
post #4 of 5 Old 01-23-2020, 08:30 AM
Registered User
222Doc's Avatar
2012 JK Wrangler 
Join Date: Sep 2011
Location: Lake Havasu City
Posts: 9,518
super charger would kill the power train warranty as would 38s....38s on d44 even gen 3 ones plan on things wearing out fast. Other issue will be that electrical steering pushing 38x13.5s. In a jk that would need Min. Big bore steering box and hydro would be better. JLs? they dont use the same steering as the past so i have no idea how simple or cost to make that have more power to steer.

this a street jeep for looks then stopping it might be the bigger issue. Other then why one would need 38s for street.......

Jl has the 8 speed i think the first gear in that is a step lower then the Nag1s that was a step lower then the 42l in the older jks and tjs. This will help a lot out of the whole. i would say its close to how your jk was nag1 and 5.13. The Jl on 4.1s would be close to the same on 37s both. Now you dont gear things for 1st gear most times. The Zf8 has two overdrives if i recall. .76 and .87? The nag1 had only one over drive at .87. the .76 is like a 42le's overdrive.

So to make use of that .76 means a lot of gear for 37/38s or the .76 wont be useful. Not sure but i would bet if it dont ever see 8th or it will "hunt" it. Now say you had 5.13 in the JL with the 37s and a zf8 . your old jk would get smoked in a 1/4 mile. do to the zf8's what is it 4.5:1 first gear and 5:13 rear gears would have some fast shifts out of the whole. Might break something. Would be best 35s and 5.13 with that .76.. bet it would smoke tires through a few gears if you turn off the TC on 35s......would use 8th well as well.

Home of the Parker Desert Splash

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
222Doc is offline  
post #5 of 5 Old 01-29-2020, 06:35 AM
Registered User
2020 J-Series Truck 
Join Date: Jun 2003
Posts: 3,687
The new 3.6L engine with it's lower RPM torque mated to the new 8-speed trans. is a game changer. Handles 35s with ease and guys with 37s are generally happy. Having said that, with 38x13.50s you're going to have well over 100 lbs. of mass per corner and that's really starting to push it for ANY vehicle. You'll probably want to regear it after you drive it for a while.

Current Jeep: '20 JT Gladiator Max Tow w/ mods

Prior Jeeps/trucks/cars: Too many to list
WXman is offline  

Quick Reply

Register Now

In order to be able to post messages on the forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome