CBR F4i - Shifting/Clutch Questions

[Mikey]

Hey Guys,

I was wondering if anybody knew how much force is required to engage the clutch, as well as how much force is required to engage a gear. Any help would greatly be appreciated,

Thanks
Mikey
Shifter/Clutch Team Leader

[Mikey]

Hey Guys,

I was wondering if anybody knew how much force is required to engage the clutch, as well as how much force is required to engage a gear. Any help would greatly be appreciated,

Thanks
Mikey
Shifter/Clutch Team Leader

[Sam]

Stick a big bar on the gear and clutch, hang weights off it. wait for click.

Sam Graham
Engine Group Leader 2003
UQ Racing

[boss451t]

I used a fish scale and pulled on the shift lever that is on our car. By measuring the difference from where I pulled to the pivot and then from the pivot down to the shift cable node I was able to calculate the force to pull the cable as we have it on the car. SO friction of the lever bearing, friction in the cable housing, and force at the engine to shift were all accounted for. I calculated 44 lbf. FOr the clutch I did something similar and pulled on the clutch handle a certain distance from the pivot. Got that to be 15.25 lbf in the handle. Hope that helps....and you may want to try some similar testing to get your own numbers.

Mark Thompson
Virginia Tech
Engine Team Leader

[-]

I have not done the calcuations myself for the forces need to move the shifter, but I remember that people in the past calculated the force and it turned out that with the motor running it was somewhat different from when the motor is not running. You might want to take this into consideration. As for the clutch, I have no idea, good luck.

[Ryan Schoffer]

the heaviest shifting force is going to be with the motor stopped - if you spec the system to shift then, it will have no problem when the car is moving

Vehicle electronics leader

www.ucalgary.ca/fsae (http://www.ucalgary.ca/fsae)

[Mi_Ko]

I think the force is specific for every engine. You'll have to measure it yourself.

Just my feeling for our engine:

For engaging gears should be 30N enough.

Our clutch is pretty difficult to engage. Over 200N I think...seems to be the biggest problem for automatic shifting. Maybe there is something wrong with it... we will fix it this year.

2002/03 University of MARIBOR - Team Member

[vern]

Every clutch will be different but our F4i clutch required a maximum of ~175N to fully engage measured with a spring balance.
Joe

[Chris Boyden]

We did the same thing as Mark (VT)and used a $5 fish scale that went up to 50lbs. It's probably not the most accurate way of measuring. But definitely helped size and select the linear actuator that we used for our push button shifting. We came up with 30-35lbs initial force with about 35lbs final on an F4i. We also tested a 99 R6 which seemed to require less force initially ~20lbs, but had a final force of 35-40lbs. The friction of the shift lever and cable could add about 5-10lbs additional force.