Elaine wrote:
Thanks for moving this thread - I had thought that it should be in the motorcycling thread, but I guess this is the best place for it.
Re stability, I think that the comments from Duncan MacKillop, advanced motorcycle trainer, are my best response to that question.
"I too was involved in the initial consultation for the Saferider project and like the other trainers, I could immediately see that there was a serious problem with trying to achieve safety through interfering with the throttle. At my riding school, the very first thing we do is to get the students to understand what the throttle actually does and not what they think it does.
The primary function of the throttle is to turn our bikes from something that is statically unstable to something that is statically and dynamically stable. Few of us can keep our feet on the pegs and balance a stationary bike simply by using shifts in bodyweight, but this all changes once we open the throttle when the task of balancing on the bike becomes immensly easier. This change in stability state comes from the forward motion of the bike and nowhere else. Unless we ride in a land that is on a permanent downhill slope, then the throttle is the only thing that can give us the stability we need.
The secondary function of the throttle is to control our suspension. Most riders know that the forks extend when we open the throttle, but around 90% of my students think that the rear suspension compresses at the same time. Few riders appreciate that the rear suspension also extends when we open the throttle. This extension of the suspension when we open the throttle gives us lots more ground clearance which is essential in any corner as well as putting the suspension in its sweet spot.
Finally, the throttle does the relatively simple job of changing the speed of the bike.
With an open throttle, a bike is more stable, has better ground clearance and has improved suspension function. With a closed throttle a bike is less stable, has less ground clearance and reduced suspension function. Of these two states, which is the safest?
Most government agencies like to believe that the throttle only makes bikes go faster and therefore safety can be improved simply by closing the throttle and slowing things down.
Helping these agencies to understand the somewhat counterintuitive relationship between throttle, stability and ground clearance will go a very long way to improving motorcycle safety rather than the somewhat dubious functions envisaged in Saferider".
Hope this helps
Nobody had been talking about closing the throttle, until now. Are you really claiming (now) the plan was to completely kill the power? If not, what you are saying does not apply, does it?
I think the best way to fight a bad suggestion is for the comments to be well targetted on exactly what that suggestion would mean, rather than general statements, which do not exactly apply to what is being talked about.
I really do have a very good understand of the dynamics of a motorcycle, but wanted a very clear statement of what instability would be caused by the suggested proposal.
On a technical point, a motorbike is never statically stable, but as you point out under power is dynamically stable.
So, what exactly is the proposal again?