02-05-2018, 02:48 AM
(02-05-2018, 01:57 AM)Guth_imp Wrote: As I recall, back when the CB1100 was first released here in the States, road tests showed that the speedometer was surprisingly accurate. That would have been with a fairly fresh set of tires. As tires wear and become smaller, I would imagine that the speedometer reading would become a bit faster over time but I have no idea to what degree.
My 2014 standard has the most accurate speedo of any vehicle I have owned.
The speed sensor is on the rear.
If a new tire is 26" OD, the circumference would be 81.64" (pi x D)
If worn is 25.5", the circumference would be 80.07"
If 60 MPH is indicated with a new tire, then a worn tire (based upon 1/4" less tread on the radius) would indicate 58.84 MPH.
81.64/60 = 80.07/X
A new tire indication of 100 MPH, would be be 98.08 with a worn tire...again, that is based upon a 1/2" difference in diameter between new and old.
81.64/100 = 80.07/X
Not a big difference, about 2% regarding circumference, which is proportional to speed.