Electronics, Lighting, & Gadgets - Going 47 MPH Standing Still

I recently locked my bike to a bike locking posts just outside the hardware store. I was surprised to see that my cateye vectra wireless told me that I was going 47 MPH. I looked around and saw no other bicyclists.

What do you think was triggering the sensor or the computer?

The bike post probably is near an underground electrical cable. I am more surpised that it didn't tell you, you were going 60mph. A neon sign transformer can do that or any reasonably high voltage electrical source can trigger the sensor.

torgrot

I am more surpised that it didn't tell you, you were going 60mph. Well, the computer might be getting a signal that tells is that the wheel is rotating either 60 or 120 times a second (it could go either way -- it depends on the specifics) but how many mph that translates to would depend on the tire circumference you programmed into it.

Though 60 cycles per second on a 28" (roughly 700c) tire would work out to 300 mph. Obviously not all of those cycles are coming through as valid.

I have the same thing happen if my bike is in the car or past buildings, it jumps to 70mph or so.

I have plastic railings around my porch and my wireless typically reads about 90 mph when I lean my bike against it. I can get some really high average speeds for my trips unless I reset the computer before I start. I once had an average speed of 48 MPH for a 10 mile ride and I thought Tour de France here I come, then reality hit and I realized there is no way I could do it after I got passed by real old gentleman who looked like he was riding to his own funeral. I attribute the erroneous readings to static electricity.