# Shifting Torque

Hey there! I have been working on a servo shifting for Yamaha WR450-F for which I have to evaluate the average shifting torque? And the critical factors on which its value depends?

How would we know that, if there no reason to know that until you invent the device you are talking about.

I am assuming you are talking about linear movement torque to overcome the shift drum detent.

How would we know that, if there no reason to know that until you invent the device you are talking about.

I am assuming you are talking about linear movement torque to overcome the shift drum detent.

I am working for Formula student car.Yeah I am talking about the linear movement torque or the amount of rotation in degrees needed for a single shift. I just wanna know that on what factors it depends? And if any of you guyz have idea about that, please share..

Thanks

Get an angler's scale, or any other that can weigh something hanging on a hook, and see how much force is required to accomplish a shift into gear with the engine idling.  Then correct for the shift lever length.  Figure you will need about 3-4 times that much torque for a good positive shift.

I don't mean to be a jerk, but it seems like this is an extremely easy problem you have.  Force x Distance = Torque.  Go shift the motor in question at different angle speeds and measure the force needed at a specific distance.  Like Gray said, a solid factor of safety is good too.

Make sure the actuator applies the force over enough time to complete the shift as well, not just an impact, include a dwell time at the peak.

Thanks for attention!

Well, I know how to evaluate the torque..The question is on what factors it depends?  When engine rpm is high , will there be any change in the required force? Does downshifting force is exactly equal to that for up shifting?

Most air shifters I've seen for drag bikes kill the ignition for a bit so it can shift.

Otherwise the trans is almost locked in gear.

I think that you should look into Ducati's " Quick Shift" technology. I had the pleasure of riding the 1299cc street bike so equipped .

It allows full throttle shifts without touching the Throttle or Clutch! It works on down shifting as well. That v twin was a beast and the shifting was amazing! That said I don't see this happening on a dirt bike.

YES, engine rpm and load will effect shifting torque.  I would expect LOAD is your most prominent factor, once you get past idle (too slow and you risk not engaging the dogs).  Killing the engine momentarily (or clutching/blipping the throttle) will be necessary to shift well with this setup.  I assume the driver is still controlling the clutch/throttle, so some driver training can overcome this.