I think these units basically measure rotational speed and I don't think cup
size would change that. The length of the arms might be important though.
Is there a calibration adjustment for your unit? If so you could install
anything and then adjust the reading to be the same as your neighbours.

"Steve Inglis" wrote in message
...
The Anemometer cup assembly has flown way from my old Plastimo masthead
unit
and I cant get a direct replacement.
If I manage to fix a similar sized alternative will it read wind speed
correctly even if it is a slightly dissimilar cup size and weight ?

Hope you havent read this thinking I'd posted to the wrong NG ...