I was under the impression that most wired cyclometers with a magnetic pick up, especially the ones from Sigma Sport could be set up to run a pair of cyclometers from a single sensor. I have two Sigma BC906 cyclometers that I have tried to set up this way. I carefully spliced in the extra length of wire to go to the stoker, and I know it is done properly, as a cyclometer works well in either position. I made sure the polarity was the same for both units as well. My set up works fine when the bike is rolling. I get the same speed on both cyclometers. However, when I stop, there seems to be some cross talk. Initially both computers read 0 mph, but then one or the other reads 4.5 mph. I find that it is not always the front or the back, nor is it always one unit or the other. The problem with this is not so much the 4.5 mph when stopped, which we could ignore, but it totally messes up the odometers. I tried putting identical fresh batteries in both cyclometers, and this did not change it. I also tried swapping the polarity, but that was even worse, not surprising. Any ideas? If not, my next plan is to unsplice the two and mount the second sensor on the other side of the fork, but that feels like admitting defeat.
Thanks for any insight you can provide.