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Discussion Starter #1
I have some questions about this stuff on my 2019 R3.

I've always used this gearing calculator (or similar) and had great success with it (it's been accurate and super useful), with many different motorcycles over the years: Gearing Commander ⚙ .

At a speedometer-indicated 85 mph in sixth gear, my tachometer shows about 9,200 RPM. However, the gearing calculator I've referenced above says it should be at about 8,600 rpm [but at 8,600 rpm indicated, I'm doing an indicated 80 mph]. Is the displayed RPM simply derived from whatever value this model's speedometer displays, or is it actually measured separately? I assume it's not tied to the speedometer value, because if it were, it should read about 8,600 (unless the calculator is wrong, but I've checked all the numbers in it, and it looks like they're all correct). It doesn't make sense that the tachometer is actually accurate, because that would mean my speedometer is actually reading LOW (showing 85 mph when I'm actually going 90 mph...which I should be when the engine is ACTUALLY turning 9,200 RPM with stock gearing).

So basically... how is the indicated tachometer reading measured or obtained by the instrumentation unit?

Related to that^^...will the indicated RPM be different at a given indicated speed after a gearing change (e.g. 14 to 15 tooth front sprocket)? In other words, will the display unit still show 9,200 RPM on the tach when the speedometer shows 85 mph after a gearing change, or will the displayed RPM be different (at the same indicated speed) after a gearing change?

I'm looking at buying a 12oclocklabs SpeedoDRD and programming it to indicate actual speed after I figure out what gearing I want to run and what the speedometer should display at any given speed after that (the % discrepancy between indicated speed and actual speed) via GPS. That part is easy enough for me to figure out, but I'm not sure about the indicated RPM.

I guess that, assuming the gearing calculator is correctly calculating the relevant values, I can always just figure out what the tach should be reading after I recalibrate the speedometer to display accurately (after gearing changes). Then it would just be a matter of also recalibrating the tachometer to match whatever the then-accurate speedometer displays (e.g. if I were to change to 15/43 gearing and then program the tachometer to read 8,100 RPM -- if necessary, and if possible...). I'm not sure if the SpeedoDRD is capable of altering the tachometer value.

Sorry for all these questions and the disorganized nature of this post...it's late, and to be honest, I'm having a hard time wrapping my mind around some of this stuff.

Any input is appreciated.
 
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