I have a 2006 2500 diesel and would like to know how to recalibrate the speedo if I go up in tire size. my truck has a 410 rear end and I woul like to lower my rpm at highway speeds Thanks randy

 

You can take it to the dealers and they can program it for your new tire size or a programmer like the Smarty will let you reprogam your tire height.

Ken

 

You will hear from the smart guy here soon enough. . but the 06 like mine has very limited choices to adjust for bigger tires. I think 285 is the biggest. My Smarty arrives tomorrow, I finally get to set mine right.

 

smarty allowed me to adjust my 37's i'm sure it can go bigger as well