Sorry, I forgot to divide rpm by 60 to get revolutions per second.

Here is (I hope) the correct calculation:

motor shaft is running at 11050rpm

That's 184.17 rotations per second

40 spokes, which I have to measure on and off, so 80 transitions per second.

80 x 184.17 = 14733 changes in state per second.

I think.

Which seems perfectly measurable. Or am I wrong...?