Originally Posted by Jeeperforever
I've heard many rumors about this but i don't know if it's true. I'm about to put a 4" lift, 37" tires, and a 6.1l hemi in my 2011 jeep wrangler unlimited Rubicon and I heard that your dash will read wrong with all those parts on it. Is it true that your dash could say your going 50mph but really going 60mph? Please help
Yup, it's the truth. You can ask the tire shop if they can flash your Jeep to fix the discrepancy...some will, some won't.
Or you can buy an AEV Procal for $150 and do it yourself. The Procal will also allow you to adjust the sensitivity of your TPMS sensors, if you keep em, and turn off the warning light and chime if you don't. And it'll allow you to adjust to a higher idle speed when running a winch (if you've got an auto). And change the shift points on an auto after installing bigger tires, etc.
Handy little gizmo.
Get one here:
ProCal Module - Electronics - Shop By Category