Transmission that can change gears while stopped?

[ice109]

i know on my bike i can't change gears if I'm not spinning the wheels and i know in a manual transmission you can't change gears really unless you're moving. anyone know of a transmission system that can change gears while stationary?

 

[Danger]

With an automotive tranny, it depends upon what position the gears are in when it stops. If you try on any parked (standard) car, there's a good chance that you can shift to at least one other gear selection... assuming that you can get out of the one that you're in.
I take it, though, that you mean consistently shift from any gear to any other. I don't know of one right off, but there's a lot of new stuff out there. Maybe some of the CVT's or dual-clutch units can do it.

 

[AlephZero]

When the engine is running and a manual transmission gearbox is in neutral with the clutch up, one gearshaft is rotating. So there is no practical difference between pressing the clutch pedal and selecting any gear you want when the car is stationary, and changng gear when driving.

If the engine is off and the car is stationary, then it can need a little "gentle persuasion" to select any gear, but it's usually possible.

 

[ice109]

When the engine is running and a manual transmission gearbox is in neutral with the clutch up, one gearshaft is rotating. So there is no practical difference between pressing the clutch pedal and selecting any gear you want when the car is stationary, and changng gear when driving.

If the engine is off and the car is stationary, then it can need a little "gentle persuasion" to select any gear, but it's usually possible.

there is a difference, if the the input shaft is spinning then the synchros can do their job, otherwise you grind the dogteeth of the collar and the gear. if you're stopped then then synchros don't synchronize the gear and the output shaft and you are grinding teeth.

i'm curious about a tranny being designed to be able to switch gears at a stop

 

[chroot]

The internally-geared hubs on some bicycles are capable of changing gears while stationary. I don't know much about their design, other than that they are based on planetary gears.

http://en.wikipedia.org/wiki/Hub_gear
http://en.wikipedia.org/wiki/Rohloff_Speedhub

- Warren

 

[turbo]

In most manual transmission vehicles (that's all I have owned for many years) you can shift from one gear to another while parked. Even if there is some gear-lash, that can be relieved by depressing the clutch. At the age of 10, I learned how to drive in a late 40's Willys Jeep with no clutch (throw-out bearing could not disengage) by starting in in low and speed-shifting. Later, my father got the clutch fixed so it was easier to drive, though I could always speed-shift that rascal without a hitch.