Originally Posted by markk900
The calculator bases everything off of a reading of indicated speed and indicated rpm from the creator of the calculator (ie. 5300 rpm in 6th at 60mph on a specific brand of tire). Everything else is a % of that single reading, so there is a great deal of variability that could be had.
Use it as an approximation only, though most readings should be reasonably close (ie +/- 500rpm).
There also appears to be one insignificant error - while the calculator deals with the primary ratio change, at least in comparison to my 95 SE the first gear ratio in the 94+ column is wrong. According to my manual it didn't change from the earlier bikes.
That's exactly how the calculator was developed. My bike, my instruments. It was intended as a predictive tool for the effect of sprocket changes.
The tachometer, being electronic is probably the more accurate instrument and we all know the speedometer is several mph optimistic. However, IF the observed speed and rpm cells in the spreadsheet are adjusted for YOUR bike (the tire is the biggest variable), the calculator should be very accurate since the mathimatical relationship of the gears is fixed. Keep in mind the indicated speed on the DR350's mechanical speedometer may NOT match up at all speeds but that will be due to the limitations of the crude rotating magnet instrument.