Problem with Cateye Velo8

[potsy]

Have had an intermittent problem lately where it doesn't seem to be registering anything,display is on but sometimes when I glance down it's showing speed as zero,magnet and sensor are very close together so what could it be? Battery? sensor?
It's about 9 months old,and used in all weathers.

 

[mattsccm]

The sensors on those are not the best. Water and dust gets in where the wire enters. if its got wet dry it out. If its dusty try and clean it. Water?? then see above. Not a certain fix but it reflects my problems with them

 

[rh100]

Check the magnet has not slipped down/up the spoke, I think the vertical alignment affects it. Also, check the contact points of the bracket are not covered in anything.