front wheel size 21" vs 23"

[Cartman_tp]

Couldn't a new abs plate be fabricated with more slots? Circumference of 16" rim is 50 1/4", circumference of 21" rim is 66", the new rim is 1.31% larger. So if the stock abs sensor has 30 slots (just a estimate, I haven't counted yet). Then take 30*1.31= 39. Then new abs would need to have 39 slots. I understand that these figures do not take tire size into account, would actually have to make the sensor off of there circumference. Am I off in my thinking here? This shouldn't be too tough to fabricate.