I purchased the optional brake sensors from Paul so I could keep my original V rim brake handles. It would appear they sense the brake cable moving when applying brakes and cut motor power. I am unsure where to put the units, right up against the brake lever or down by the rim brake assembly. Maybe it makes no difference but I note the attached plug and play sensor cable is quite long. Makes me think they go are the brake assembly rather then the lever with a lot of cable to find a home for. I welcome your experience.