View Full Version : Question about transmission.

05-12-2006, 11:07 AM
Hey guys.

I was wondering how a 2 and 3 speed gearbox in an rc works. As I don't have any rc's with two or three speed gearbox (I only have a couple of electric cars and an Inferno mp 7.5) soo I can't find out myself. I do understand how a car transmission work, but not an rc's. What I don't understand is, how does it shift to second/third gear without any help from a servo or anything? How does the mechanism work? and what happens? I was just very curious ;)


05-12-2006, 04:56 PM
Please... somebody say something....

05-12-2006, 05:53 PM
it is a piece of cake really. Inside any regular 2/3 speed tranny are 2 gears ( simple breakdown) and inside of the second gear is a little clutch pawl with an allen screw to adjust shift points. as the said car accelerates the centrifugal force from the spinning force the claw outward, thus grabbing second gear and going faster!!!!!!!!

05-12-2006, 06:15 PM
Joose there are 2 types of automatic rc tranny designs. The first design uses a pawl that must overcome the resistance of a spring , so it can swing outward and engage 2nd gear. While this is happening the oneway bearing in 1st gear acts like a clutch and disengages 1st gear so it freewheels creating less resistance in the drivetrain. The second design mostly appears on highend on road racers like the Serpent 950 etc. This tranny is based on two giant sized clutchshoes these shoes are connected togather with 2 springs which keep the clutchshoes from flying out engaging the 2nd gear housing. But when the rpms get high enough and the cluthshoes overcome the springs the shoes fly outward and engage 2nd gear housing ,that the 2nd gear spur is attached too causing the tranny to shift into third. This tranny also uses a oneway bearing in 1st gear so 1st gear freewheels when second is engaged.

05-13-2006, 03:02 AM
Thanks guys...

05-14-2006, 12:00 AM
the second type engages smoother, and has a better power transfer to second gear, and any car from a R40 to a MRX-4 has them

basically any car that was built to race