Di2 doesn’t know or care what chainwheel/cassette you have* so davef’s theory seems more likely. (* except when setting up synchro)
Yes, but if you were designing a system to log/display Di2 gear data, you’d need it support everyone not running synchro too.I mean the only way to find out is to test it - e.g. log a ride without your cadence sensor and see if it still shows ratios. But my money is on it not using the Di2 data.
Kim, you are very bad!
It's presumably assuming the crank length, too. Speed and cadence only allows you to calculate development.
Quote from: Kim on 26 August, 2019, 11:11:48 amIt's presumably assuming the crank length, too. Speed and cadence only allows you to calculate development.No. It is only displaying the ratio of front chain ring to rear cog so 52/13 is shown as 4.00. This also means wheel is rotating 4.00 times for each crank revolution. Wheel rotation rate can be picked up from wheel sensor or calculated from speed and circumference. Although crank length affects overall gear ratio, this is not shown in this metric.