I do not think the weight is a problem. The magnet is tiny and very light as with most common bike speedometers. like the Bell F20 computer. Compare this to the weight of a car tire. That is very heavy compared to a bike and they only have to use a small amount of lead to balance it. I use the Bell model and have never had a problem with it. I would think if the company knew there would be a common problem with this small weight they would not have used this design for the speedometer.