Force needed for shifting

[ahmad sanad salim]

Hello

How can I measure the needed force to make the drum rotate , for Honda CBR600rr engine .

And thank you so much.

Ahmad

[ahmad sanad salim]

Sorry,

The needed force and ANGLE in order to shift.

Ahmad

[jd74914]

Force can be pretty easily measured with a spring scale attached to the factory shift arm and angle can be measured simultaneously with a protractor. Note that this force/angular displacement will be approximate. If building an automated system to do this you need to allow for some "tunable parameters" for tweaking once everything is built.

For what its worth, if you need to ask how to do measure shift force/displacement, I would strongly suggest using a very simple mechanical linkage. The electronics you refer to in your other thread are infinitely more complicated and it does not seem like you have a good handle on the basic fundamentals.

[Charles Kaneb]

They're small enough to allow the use of 3/16" rod ends at each end of the shift tube.

Going from a cable to a tube shifter was the biggest single improvement I've ever seen on a car's driveability.

[dprmb]

Charles, can you elaborate on what you mean by a tube shifter?

[jd74914]

I'm not Charles, but I would venture a guess that he means a shifter with solid (tube) linkage as opposed to one with a morse (push-pull) cable.

[Charles Kaneb]

Jim,

Exactly.

If you do it right, you do not need any spherical bearings and can just have yokes with oilite bushings.

If you're not THAT careful, even a bent tube with two sphericals in single shear is preferable to any cable shifter.

[LuizOliveira147]

Wouldn't you be worried about the tube buckling under a shift? And what material are these tubes made of, if I may ask?

I love the idea!

Thanks!

[Charles Kaneb]

1) Yes. You have to calculate the force on the tube and the critical buckling force for it.
2) Steel. Think about how hard your driver will push on the gear lever when the thing's not shifting right, then do an FBD on the linkage and find how much force that puts on the tube, then go look at what size tube you need.