How does one calibrate a speedometer?
The GPS and my bike do not agree. 120KPH on the bike speedo is 107 according to the Garmin , which happens to agree exactly with the speedo in my Toyota. The good news is that as long as I keep an eye on the needle, I should not be getting a speeding ticket. It could be a disaster if the error was the other way round.
On the other hand, according to my bike odometer, I rode 401 km from Bindoon to home, whereas Google says the distance is 362 km. That is quite a variation and I suspect it means I am adding mileage and depreciation to my bike at an excessive rate. What can be done about that?