How does it work? Is it some kind of centrifugal clutch that shift the driving to the next gear? It looks real simple but i cant understand how they work really.

Any drawbacks with them comparing to normal a gearbox such on a car or motorcycle? What about variator as used in snowmobiles? Wouldnt they be great?

if u take of the second gear u will see that there is a little wedge in the gear going in closer to the center of the gear.[img][/img]

As the engine gains speed the gears turn faster and faster .

as this happens the force pulls out a little bit of metal (not on the gear ... what the gear is attached to) which attaches and hooks onto the second gear where the wedge is. the car will now being running in second gear. as the engine slows down the force isn't as big and the spring has the bigger force than the engine and the little metal bits moves back into its original place which puts the car back into 1st gear.

[&:]

Thanks, i think i get it.

Will i notice a rpm drop in the sound when it change gear? I heard you shouldnt have too much difference between the gearings but thats maybe model related. How big gearing difference is used normally? I personally have a 23cc 1/6 scale FG marder so i think it should be able to have pretty big difference in matter of engine power cause of its high torque.

any change in gearing would not be any larger than from 5:1 to 6:1 or so. yes you will notice a drop in the rpms of the engine because of the suddenly increased load on the engine. but you need to remember that i am talking about nitro engines that run at insane rpms but mith nearly no torque. gas engines are much more powerful not in horsepower but in torque. are you talking about a 2speed in a large scale gas car or smaller nitro car?

1/6 scale 23cc gas car.

neap38-
Is what you mentioned above a "finger type" 2 speed?

ermmm [&:] im talking bout the centrifugal force type gears.

all it is is a centrifugal clutch and a one-way bearing. as the shaft turns faster, the clutch engages the second gear and the one-way bearing stops the whole thing twisting to shreads.

There are 2 types of 2 speed trannys. One is called a "finger type" and the other is called a "shoe type". The finger type was mentioned above but the shoe type wasn't. As you can guess the shoe type is almost exactly like the clutch on the engine. Instead of using an interlocking peice of metal, it uses plastic shoes that grip the bell on the second gear.

thats what i meant. forgot to put the shoe bit.