Originally Posted by
ItsJustMe
That thing looks like it would be dangerous at any kind of speed. I usually get up to 30 MPH or so on my commute, I would think that anything with that kind of weight on it at 30 MPH would make the bike a bit unstable.
I've seen the Monkeyletric and Hokeyspokes ones on bicycles doing 35 mph down a hill and they didn't seem to be a problem.
The key is to get two or three and make sure they're all at the same distance from the center and arranged as evenly as possible across the wheel. If you do that, you won't have any problems with balancing.
If you try and do it with just one, yes, it'll cause balance problems and your tire will vibrate as you ride.
Note that the forces involved become pretty significant at speed. If you've got a bicycle that's going 35 mph and the tires are 26" in diameter, that corresponds to
a centrifugal force of 75 g's at the outside of the tire. The acceleration gets smaller as you get closer to the center, but now that I've done the math, I think I might have to agree with you that I wouldn't want one of these on a wheel that goes that fast. I've seen them on bicycles going that fast and nothing bad happened, but that's a lot of force (well, mass * acceleration = force), and if something did break, all sorts of exciting things could happen. (And in this case, I mean
exciting in a bad way.)