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Discussion Starter #1
Jeepers, will the AEV Procal adjust the gear geometry settings along with the speedo settings. Seems third gear on my auto trans is running higher revolutions then when I had stock tires.
 

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The one in bold below? I think that's what you are asking.

Large tire recalibration (Restores the vehicle's speedometer/odometer accuracy following the installation of larger-than-stock tires)
Axle gear ratio recalibration (Resets automatic transmission shift points to maximize the benefits of an axle gear ratio change)
Tire Pressure Monitoring System recalibration
Note: Lowering a vehicle's tire pressure below that specified by the vehicle/tire manufacturer may create unsafe handling characteristics. AEV assumes no responsibility for a vehicle's handling characteristics or the safety of the vehicle's occupants.
Daytime running lamp activation/deactivation, and lamp location selection
One-touch turn signal activation/deactivation
Engine idle speed options (Improves winch performance and battery charging capabilities by temporarily increasing engine idle RPM)
Steering wheel centering (Provides for spot-on steering alignment)
Clears Engine Diagnostic Codes
Reprograms TCM for gear change in 2012+ models to prevent "limp mode"
 

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If you just put bigger tires on you just need to do the tire size re calibration . That in turn will
Correct speedo and shift points for tranny. You would only use the axle gear ratio calibration if you actually
Changed the ring & pinion gears in the diff's
 

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as long as you are calibrating for proper tire size. It won't work trying to calibrate for 37" tires if you have 33's
 

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Calibrate to the true size of the tire as it sits on your Jeep too. I have 35" BFG KM2s at 30 PSI so when I measured them they were actually somewhere close to 34".
 

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^ This. I calibrated mine to the height of my tires when they were new, and it was great. Over two years the tires wear down, and when I went back and retested the speedo vs the gps, I found it was off about 2mph. That doesn't seem like much, but it adds mileage to your odometer. I remeasured the tires and they were a half inch shorter. Recalculated the Procal setting and I'm on target again.
 

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Discussion Starter #10
Thanks again. Another question. I am running 285/75/17 and ran cold psi from 30 To 40psi currently at 33. What are you running the psi at? I will do a chalk test as soon as the weather breaks but am curious.
 

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Thanks again. Another question. I am running 285/75/17 and ran cold psi from 30 To 40psi currently at 33. What are you running the psi at? I will do a chalk test as soon as the weather breaks but am curious.
I ran toyo 285/75-17 for 20,000 miles and ran them between 26-28psi on my jkur I gave up on the chalk test because it looked the same no matter if I had 16psi or 34psi. 10% is what lots of experts like ie measure cold and then go for a 10 mile drive and psi should rise 10% if less then too much psi if more to little. use 33" to set your procal and you will be close maybe 32.75" or 33.25" but start with 33" and adjust up or down if speedo is off still.
 

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I like 29psi with warmed tires, that said, my psi fluctuates a lot with weather temps. Anywhere between 26 cold, to 34 hot. I had a day in the past few weeks where it was freezing in the early morning and my tires were at 26 or 27 psi first thing. We had a warm front and sun come out and it was in the 70's later that day, or maybe that was the next day. At any rate, the psi got up to 34 in the afternoon sun that day. I would normally have dropped it down a bit, but the weather is too fickle to do that this time of year. Heck, tonight, we're cold again.
 
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