Speedometer Calibration with Larger Tires

[RadoPhan]

So I was thinking about calibrating my speedometer but then this happened. I went from stock TB tires 275/65/18 to 295/70/18. When I was on stock, my speedometer always matched the speed that displayed on my Waze Apple CarPlay. Then when I got my new tires, I noticed that the speed was off 3-4 MPH at higher speeds, slower on speedometer than Waze, which was expected. This happened for about a week. Then suddenly, my speedometer speed is now matching with my Waze speed. Waze has never given me any issues before and it estimates speed based off of GPS tracking. Also, it feels like I’m going 75 MPH when the speedometer says it too but I don’t trust that. Does anyone know if the newer trucks calibrate on their own or am I crazy? I almost want to have someone drive next to me and tell me their speed to compare to mine.

 

 

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[Jav_eee]

You could also try a separate speedometer app to verify...


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[RadoPhan]

You could also try a separate speedometer app to verify...


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Any recommendations on an APP that has worked well?


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[BetaX]

Do you have an apple watch? We put my wifes on the bicycle app and it matched waze for me.

[Jav_eee]

I use one called speed box


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[MAK2013]

The new trucks do not have the ability to synchronize their speedometer if you switch tire sizes. It has no idea what size tire you put on there. Both Rough Country and Hypertech sell speedometer calibrators. I’ve had better results with Hypertech

[RadoPhan]

Do you have an apple watch? We put my wifes on the bicycle app and it matched waze for me.

Yeah I’ll give that a try as well thanks


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[RadoPhan]

The new trucks do not have the ability to synchronize their speedometer if you switch tire sizes. It has no idea what size tire you put on there. Both Rough Country and Hypertech sell speedometer calibrators. I’ve had better results with Hypertech

That’s what I was thinking too but just can’t explain why Waze was accurate for the 7 months I’ve used it then the day I changed my tires it was inaccurate for a week afterwards but now back to matching my speedometer. I was planning on using Hypertech but wanted to test a few things out before I spend $200+


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[MAK2013]

1 minute ago, RadoPhan said:

That’s what I was thinking too but just can’t explain why Waze was accurate for the 7 months I’ve used it then the day I changed my tires it was inaccurate for a week afterwards but now back to matching my speedometer. I was planning on using Hypertech but wanted to test a few things out before I spend $200+


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I mean even if the speedometer can somehow calibrate itself (which I find incredibly unlikely) you still need a calibrator to get your shift points correct and get your ESC set to a larger tire

[davester]

Just a note, but read through your warranty, as I believe you'll find at least part of your warranty is void if the odometer isn't calibrated properly.

[justanengineer]

If you have a Global B truck it has the ability to recalibrate for different size tires using the OnStar GPS signal, wheel speed sensors, and other sensors. I can't remember if it is ignition cycles and or distance but it's probably a hundred miles in a few ignition cycles before it implements the new Cal.

[M1ck3y]

11 hours ago, justanengineer said:

If you have a Global B truck it has the ability to recalibrate for different size tires using the OnStar GPS signal, wheel speed sensors, and other sensors. I can't remember if it is ignition cycles and or distance but it's probably a hundred miles in a few ignition cycles before it implements the new Cal.

 

Rough or smooth surface inside intake runners?