[Harlan Ortiz]

I couldn't change it either. Here is a lifehack I did:
Convert your necessary speed limits with something like this: https://oneconvert.com/unit-converte...ter/kph-to-mph
Write them down on white tape and place them on or near your speedometer.
Seeing them every day will make you get used to both.

[morphomeman]

The two most important conversions (both very approximate) are as follows:

30 mph = 50 k/h
60 mph = 100 k/h

So if the posted speed limit is 50 k/h, keep her at 30 mph, a shade less than 50. Similarly for 100 k/h and 60 mph. Speed limits other than these two are quite rare.