Bigb312

Thanks for the information, I wasn't sure if I had a defective unit or what.

I bought a Superchips Flashcal to calibrate my speedometer after putting new tires, 275/65/20, on my 2015. I've used the Flashcal as directed but according to the GPS app I downloaded on my phone I cannot get it to calibrate closer than 1-2 mph. Is that the best I should expect or should it calibrate dead on?? Superchips customer support has been no help so I was hoping to get some information/help here. Thank you