Re-program speedometer & tire pressure sensors for bigger wheels & tires?

Say When · July 17, 2020

GM-Trucks.com Members:

My 2020 GMC 2500HD came from the factory with 17-inch wheels & tires. I replaced them with 20-inch wheels & tires. My WAZE navigation app shows a ~5-mph difference with my speedometer. Can GMC mechanics re-program my speedometer for 20-inch wheels & tires? Also, are my tire pressure sensors calibrated for my factory 17-inch wheels & tires? Do my tire pressure sensors also need to be re-calibrated for my 20-inch wheels & tires? Thank you in advance for any guidance you can offer. Much obliged.

Edited July 17, 2020 by Say When
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sdelam · July 17, 2020

Your looking at this all wrong, if the truck thinks you have smaller tires than it is tracking less milage than whats actually being driven. I bumped from a 275 to 295 tire, the change is small (2-3mph @ highway speed) Its close enough for me. There are some aftermarket devices to reprgram tire size but I have not tried them. I do run a Banks iDash and it has the function to correct the speed for its read out (doesnt change truck dash) and that works great. As for TPMS, the dealer should be able to adjust that. Some folks on here have reported the dealer lowering the limits for a better unloaded ride so it is possible.