How much of a speedometer change

[GasolineCowboy]

Wanting to go with the larger side wall tires on my Ram sport currently the stock tires (275/55/20) how much will the speedo/odometer change going too a 275/60/20 and if it’s worth too flash it?

 

[Bobbybob]

So...have seen this pop up on a few other posts. I just installed my larger set last night (285/65r20) and my speedo recalibrated itself using the onboard GPS! I used Waze to verify it. As I said, I read somewhere in here that some models will do that. I did not believe it myself but sure enough it did. Super cool.

 

[Bullitt02797]

Wanting to go with the larger side wall tires on my Ram sport currently the stock tires (275/55/20) how much will the speedo/odometer change going too a 275/60/20 and if it’s worth too flash it?

With the sizes you give your speedometer will be off by approximately 3%. It will read ~3% slower than your actual speed If you go with the taller tire.

 

[GasolineCowboy]

So...have seen this pop up on a few other posts. I just installed my larger set last night (285/65r20) and my speedo recalibrated itself using the onboard GPS! I used Waze to verify it. As I said, I read somewhere in here that some models will do that. I did not believe it myself but sure enough it did. Super cool.

Really? That’s awesome.

 

[1Zach1]

So...have seen this pop up on a few other posts. I just installed my larger set last night (285/65r20) and my speedo recalibrated itself using the onboard GPS! I used Waze to verify it. As I said, I read somewhere in here that some models will do that. I did not believe it myself but sure enough it did. Super cool.

Did you use Waze connected to UConnect or unplugged from the truck?

 

[Bobbybob]

Did you use Waze connected to UConnect or unplugged from the truck?

You know, I actually had it plugged in. But shouldn’t it still show the speed based on my phone GPS and not the vehicle? Will have to try unplugged and see if that makes a difference.

 

[Bobbybob]

Ha! Glad you asked that question. So the app reads the speed off the vehicle and not the GPS on the dev when plugged in. I just went out and used a handheld GPS and then my phone not connected to CarPlay and sure enough, it was off. Dang it! Wishful thinking. There are others on here that are saying It will do that and has done that, even showing pictures with handheld devices. Oh well...thanks again for asking that question!

 

[5thGenLoco]

The Rough Country calibrator is super easy and quick to use. Many dealers won't "flash" the ecm. Plus, it may take a few tries to get it correct. Nice part with the RC, it doesn't mess with other systems.

 

[Bobbybob]

The Rough Country calibrator is super easy and quick to use. Many dealers won't "flash" the ecm. Plus, it may take a few tries to get it correct. Nice part with the RC, it doesn't mess with other systems.

Thanks! Going to go route of DT Tazer

 

[dantheman]

Cool speedometer calibration calculator. https://tiresize.com/speedometer-calibration/ But it would be nice to have speedometer recalibrated to new set of tires.

 

[Bobbybob]

Tazer DT did it with no problem. It was really easy to do too!