Which wormgear ( speedometer ) do I need for the VNB6T with 10" wheels pls

This is for techtip sip; can you pls advise which wormgear do I need for the VNB6 with 10" wheels; there are currently 4 or 5 that seem to be OK: green, blue, black, red, white etc. Can you advise which one or what is the method to chose the right one to ensure it works properly and measures the correct speed. THANKS
Mig

hi ...

 

i think that you need the red one with 8 teeth Art Nr. 9446000

THANKS!!!!

Mig