Passed a speed check machine the other day(radar machine thats shows your speed on the side of the road) my speedo said 50mph, the machine showed 50mph, shouldnt it be off a little? 177mph run last summer, you think it was doing 177 actual mph? weeeee

Speedo's are usually accurate until about 60-65mph then they are off a little bit. The greater the speed, the more they are off.

I guess I should have passed that machine at 100mph, but it was in town in a 30mph zone. weeeeee

I was gps'ing both my cages and my bike and the bike was almost 100% accurate up till about 60mph then the % rate took over.
@45mph it was dead on
@55mph it was .5mph off
@65mph it was .8mph off
@75mph it was about 1.4mph off
so on and so forth