Larger tires and speedometer

Just got my 2023 Platinum a few weeks ago and it is at the tire place get some Goodrich KO2's put on. Since I went from a 265 tire to a 285 tire, I had someone at work tell me I needed to take it to the dealer to adjust the speedometer and odometer.
Is this accurate?

 

Maybe. When I went from a 275/65 to a 275/70, or a 32” to just over 33” tire, my gps speed matched the speedo. It was off before. With just the tire width you provided, can’t answer your question. Plug your numbers in here, but before you do anything verify your current indicated speed to a gps or another source to verify the accuracy of your trucks Speedo.

Mine is a 2019, not sure if the new gen has the same internal speedo works or not. Be nice if they used gps so tires would not matter.

 

Thank you. Went from a 265/60R20 to 285/60R20. I plugged it in the calculator but I am pretty tire ignorant. Looks like the Revs dropped by 17 so that probably means it effects the speed and distance traveled.

 

The difference is not material, what you need to look at is the difference between Reading and Actual, meaning, what you see in your speedometer as 70 mph you will really be at 72.2, but you can check that through the GPS/Phone, etc.

 

It does impact both. But won’t know how accurate your speedometer is until you take a drive with your phone on a navigation app that shows speed. I use Waze. Compare that to your dash speed. In my case the larger tires fixed the factory error. But odds are you will be going a little faster than your speedometer indicates.

 

No matter the difference ... Will the dealer correct the speedo?