I own a 2010 Basic Silverado,
I went from the regular stock 17's to a 265/70/18
The difference is 5 miles.
How do I know?
When I use the Waze GPS app, the app shows the speed at 75, and the speedometer shows 70.
I did try my Ford Ranger and my wife's CRV and Waze is accurate.
I can manage so if the speed limit is 70, I'll drive 65, but it is annoying