Just a week ago I wouldn't have known what you are talking about. But I followed a thread on this site about gauge restoring and I went to some site. I think some people are offering to retrofit speedometers to run by GPS. However, I'm not sure and can't remember what site is was. And I don't know if they could connect up the odometer, but it was something I wanted to look into.
If somebody could make a GPS device that would connect to the factory speedometer and odometer I'd be interested.
No more worries about the bouncing needle, speedometer gears, or lubricating the speedometer cable. Just a thought.
