[Don Boles]

Yes, it's a matter of changing the tire radius on the display.
Sounds like you need to reduce it by 10% to get accurate reading.
I just played with mine until I got it to read the same as gps.
Sorry though I can't remember how to do it, but I'm sure someone here does.

Don

 

[Don Boles]

There was when 1100 45R/46 tires weren't on the chart.

1100's are the only tire you can fit on that takes over 1000mm radius,
I believe it was 1022mm for the correct speed reading.

Don

 

[Don Boles]

You COULD do that.
In the meantime I could try a setting, do a run to compare with gps and then final set it.
From the seat.

As accurate or more so then any other way.
Coarse if your not using gps your way would be the best way.

Don