I have 2009 Dodge Ram 1500 Crew Cab SLT 2wd which came with the 17" rims. Well I just came across some OEM 20" with new OEM tires so I slapped those on becasue I like the look. Once installed with rebuilt TPMS I began driving and noticed my speedo was off. I later confirmed it with a radar gun. For example if my speedo reads 72 mph im clocking at 80mph. Since the 20" were an option for this truck why is the speedo going stupid. If anyone has had the same problem or knows a fix please help!!!

 

Go to a dealer or tire shop and have it calibrated, maybe that will fix your issue.

 

Any time you add a larger or smaller tire the speedo will be off. The 20 inch tires (if stock) are taller then stock 17s. You now have to have the dealer flash your computer with the correct tire size if you want your speedo to work right. It will cost about $80 or you can buy a programmer for $350 and do it yourself. What did you do with the factory 17s ? I am looking for some 17 wheels myself.

 

Thanks for the help Jason2922 and sking i figured it would take going to dealer for a program was trying to prevent it since my dealer is full of yahoos lol

 

Id like to get rid of them PM sent sking