2020 GT speedo Calibration

2020 GT. Just swapped to 29.5 inch tall rear tires.

I see the editor and the scanner have options, I tried making the changes In the editor and my speedo did not change at all.

The scanner says my current gear ratio value is 494.08 I don't know what this number is or how to come up with my new one.

You need to switch to calibration. Normally taken from IPC.

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Originally Posted by veeefour

You need to switch to calibration. Normally taken from IPC.

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So I switch the "learn from BCM" to "use calibration" and just input the tire sizes? Do I have to do the change in the scanner also? I'll try it when I get home today.

The scanner now lets you adjust the bcm with special functions, or use Forscan.

Quote:

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Originally Posted by LastPlace

The scanner now lets you adjust the bcm with special functions, or use Forscan.

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+2018 is a different story, bcm changes with scanner are not so obvious...wont accept certain ratios.