Originally Posted by nova
Likly cause its very hard to get a accurate reading of speed off a bike. Its easyer witth old style radar guns the lazer ones tend to hit things lieke spokes or pedals
Hit the center of a rim and speed could be in the hundreds. Least thats what the cops told me. I can sort of see the reasoning. But am unsure of the physics.
I think you mean the outside of the rim b/c the spokes towards the rim have a much higher tangential velocity than the spokes near the hub. I think the officer means that if the laser beam hits the spokes near the outside of the rim, the velocity could be artificially high because that spoke is translating at your current velocity, but it's also rotating. So you would add the tangential velocity of the spoke to the translating velocity of the bike to yield a velocity that is artificially high. This is my interpretation of that, but perhaps I'm wrong.