Downtown 300i odometer error

[TANWare]

I finally got to pace off the mile markers. at 13 miles per the odometer I paced off 12.8 miles on the mile markers on the GSP. So it comes up as aprox 98.5 miles traveled for every 100 indicated on my bike. Not too bad for a bike but tire ware will increase the inaccuracy............

Edit; this test was done trying to hold 60 MPH the entire time. I add this comment as tires at speed have a minimal expansion to them...........

[axy]

I finally got to pace off the mile markers. at 13 miles per the odometer I paced off 12.8 miles on the mile markers on the GSP. So it comes up as aprox 98.5 miles traveled for every 100 indicated on my bike. Not too bad for a bike but tire ware will increase the inaccuracy............

Edit; this test was done trying to hold 60 MPH the entire time. I add this comment as tires at speed have a minimal expansion to them...........

17 years in e- media, involved in BBS/Internet/forums and all the time there are new people that will try to quantify cars/bikes to 0,0000x of a liter, second and meter.

Btw. this only shows error of the odometer on your bike, around 60 mph mark. It varies across the range (0-top speed) and cumulative one would not be 1.5 % but more like 10-15 %, usually reported by Kymco owners. At the top it will usually show 10-15 % higher speed, across the range 6-10 %.  In the end: who cares?

To show you how not important this is, closing to 0.1 mile on your odo that was not shown increases your calculated error roughly 50 %. In extremes, if 0.1 was just turned and in the final 12.8, 12.9 was just about to show up, your error DOUBLES. So, when you measure things and use a small sample (range), you have to be very careful when interpreting results.

Btw. to take it to extremes, what about GPS accuracy? ) It can vary due to satellite positions, noise in the radio signal, atmospheric conditions, and natural barriers to the signal.
Not to mention that usage of synthetic oil might influence odo accuracy. (I simply had to add this one and you saw it coming, admit it!!!   )

[TANWare]

I have looked at the speed accuracy and it is fairly accurate accross he board. 25 MPH indicated reads 24 MPH on the local radar, have to slightly bump it over 25 to get the radar to see 25. GPS again can be inaccurate as well but for indicated it seems to be not much further off than my car at indicated speeds. My cousins son has to do 55 indicated to actually do 50 where I do almost 51 MPH (counts on the angle you are looking at it). Error on mine seems minimal, so I am happy.

Actually we are front wheel speedo/odo driven with these. So with enough tweaking we can burn all the rear tires off the rims we want without adding a single mile........................

Edit; I was interested not for long term but short term. I am looking at my present MPG from indicated and what the real MPG is. My measurment was done as at the exact point of turning 952 miles I was at mile marker 93.8 going down in markers. at turn of 965 indicated I was right at marker 81.0 instead of at 80.8. Now yes there could be a few feet plus or minus but well within acceptable error.