About the gear hubs with mid-drive ebikes:
I always lubricate the hubs with an oil sump filled with gear oil containing molybdenum:
https://www.molyslip.co.uk/2001g/
(The shell of hub contains permanently about 3 cm³ of oil).
Total weight with driver, bicycle and luggage = approx. 120 kg.
Dual...
One other solution to determine the air flow could be the hot-wire anemometer:
A thin wire, made from platinum or nickel or something else is heated up with constant current, and the voltage drop is a funktion of the temperature. And, in our case, the temperature is dependig on the air flow...
Hello everyone
I was confronted with the same problem: too little heat capacity of disc brakes. My solution is to increase the surface area.
Here a comparison of the pictures of an overheated brake disc and a new disc with additional cooling surfaces:
The material must not contain nickel...