[SUB]A seized gearbox is no joke and can lead to severe or fatal injuries, as a solo bike with a locked rear wheel is hard to control.
For example, see the experiences of Roger & Kay Lord:
http://www.vincentownersclub.co.uk/showthread.php?5121-Roger-amp-Kay-Lord
and also the accident of P C Vincent, described in P E Irving's Autobiog pages 358 and 364.
A seized engine can be similarly dangerous, but if the rider realises what is happening there is the chance of operating the clutch which allows the rear wheel to turn normally.
But with a seized gearbox there is not much the rider can do except look for a soft landing area.
I was wondering what, if anything, could be done to remove or reduce this hazard.
As far as I can tell, the most promising change would be to add a 'free wheel' to the rear hub.
That would allow the rear wheel to continue to rotate normally, even if the gearbox or engine seized solid.
The bike could be ridden normally to a standstill without the rider having to do anything heroic.
Only normal steering and applying the front brakes would be required.
There are many successful applications of 'free wheel' or overrunning clutch devices on pedal cycles, cars and automatic transmissions.
See, for example:
http://en.wikipedia.org/wiki/Freewheel
On the Vincent it would be necessary to abandon the drive side rear brake, and have the rear wheel drive sprocket connected to the hub through an overrunning clutch.
Not particularly difficult, though careful design and manufacture would be needed to ensure long term reliability with low maintenance.
A different riding style would be needed to cope with the lack of engine braking.
Effective front brakes [ disk? ] would be worthwhile.
But can anyone come up with a better way of overcoming the hazard associated with a seized gearbox?
I am looking for constructive suggestions, not 'reasons' why an overrunning clutch 'would not work'.
[/SUB]
For example, see the experiences of Roger & Kay Lord:
http://www.vincentownersclub.co.uk/showthread.php?5121-Roger-amp-Kay-Lord
and also the accident of P C Vincent, described in P E Irving's Autobiog pages 358 and 364.
A seized engine can be similarly dangerous, but if the rider realises what is happening there is the chance of operating the clutch which allows the rear wheel to turn normally.
But with a seized gearbox there is not much the rider can do except look for a soft landing area.
I was wondering what, if anything, could be done to remove or reduce this hazard.
As far as I can tell, the most promising change would be to add a 'free wheel' to the rear hub.
That would allow the rear wheel to continue to rotate normally, even if the gearbox or engine seized solid.
The bike could be ridden normally to a standstill without the rider having to do anything heroic.
Only normal steering and applying the front brakes would be required.
There are many successful applications of 'free wheel' or overrunning clutch devices on pedal cycles, cars and automatic transmissions.
See, for example:
http://en.wikipedia.org/wiki/Freewheel
On the Vincent it would be necessary to abandon the drive side rear brake, and have the rear wheel drive sprocket connected to the hub through an overrunning clutch.
Not particularly difficult, though careful design and manufacture would be needed to ensure long term reliability with low maintenance.
A different riding style would be needed to cope with the lack of engine braking.
Effective front brakes [ disk? ] would be worthwhile.
But can anyone come up with a better way of overcoming the hazard associated with a seized gearbox?
I am looking for constructive suggestions, not 'reasons' why an overrunning clutch 'would not work'.
[/SUB]