I did the air ride linkage mod and put on 35 inch tires. (2016 Ram Rebel) No surprise I have lost about 3-4 mpg on highway, and RPM's are higher now at 60 mph. I was thinking of getting the Hypertech Speed Calibrator, http://shop.hypertech.com/speed-cali...-p/3020218.htm, has anyone used this and did it work?

 

I used the hypertech speedo calibrator, and per two GPS units, it worked.

I'm running 37" tires.