Originally Posted by
FBinNY
In fact if you mount two identical bike computers front and rear, the front one will slowly pull away from the rear because the front wheel does in fact travel farther than the rear, though both don't actually pull apart.
I can't add anything regarding the OP's question, but I can confirm that this phenomenon does take place. It occurred when I began mounting a second computer on my wife's bars on our tandems. Had me confounded for a few rides. I now splice the wires together, running both computers off of the output of one magnet/sensor.