CBR 600 Gear Shift Force

[Davidimurray]

I was just wondering if anyone here had tested how much force it takes to get the CBR 600 to shift gear. If so would you mind sharing that info and the length of lever arm you used.

Cheers
Dave

[Brett Neale]

On our F4i with a 40mm lever arm, a entire upshift/downshift action took about 110N. It was the same both ways.

[Davidimurray]

Excellent. Thanks for that info

Cheers

Dave

[Davidimurray]

Hello Again

Out of interest, does anyone happen to know the force for the clutch. Shifter is coming on well, but clutch may be a challenge!

Cheers

Dave

[drivetrainUW-Platt]

Put a spring scale on it and pull it....

[Davidimurray]

I will do - seems stupid reinventing the wheel if someone already has the data to hand!

[repeatoffender]

Originally posted by Davidimurray:
I will do - seems stupid reinventing the wheel if someone already has the data to hand!

No it doesnt

How do you know they didnt fuck the wheel up in the first place??
http://failblog.files.wordpress.com/2008/01/squarewheel.jpg

[Davidimurray]

Ahh well - not much point asking anything on here - I will just go and do it all myself!

[Grant Mahler]

To me the point of this board is to ask How and Why, not What. What is merely an artifact of How and Why, and tells you nothing more than that specific situation.

[repeatoffender]

Originally posted by Davidimurray:
Ahh well - not much point asking anything on here - I will just go and do it all myself!

Thats a pretty lame comment. My point being is that you dont learn much by being spoon fed. Think of the classroom as an example, unless you went to a followup tutorial and did example after example, how much of a lecture would be able to regurgitate?

How would you answer a design judge who asks for an explanation and backup material on how you designed your shifter linkages / cables or your quickshifter system to accommodate the actuation force?

Also, just because someone here claims something to be true doesnt make it so. This forum is rife with missleading garbage.

Not trying to put you down, just trying to wake you up. It would make you a better engineer to either go directly to honda and ask for the information, or test for it yourself http://fsae.com/groupee_common/emoticons/icon_smile.gif

Yes the easy option is always alluring.

[Davidimurray]

Thats a pretty lame comment
And your childish, foul mouthed one wasn't?


My point being is that you dont learn much by being spoon fed

Who asked to be spoon fed? I simply made any enquiry as to whether other teams had any data on this subject? I supervise students myself and actively encourage them to find data
themselves. Unfortunately a lot of posts on this forum nowadays seem to be met by unhelpful comments of 'find it yourself' or 'we're not doing your work for you' rather than encouragement or at least some leading suggestions.


How would you answer a design judge who asks for an explanation and backup material on how you designed your shifter linkages / cables or your quickshifter system to accommodate the actuation force?

You explain to the judges your design methodology and how you collaborated with other teams to get suitable design data. There is nothing wrong with getting data from other sources, but as an engineer you must be able to judge the validity of that data. The same argument could be made about the TTC data!


Also, just because someone here claims something to be true doesnt make it so

No, that's why you must take it on its own merit. I have received 3 sets of values for the gear shift which all tally well. Of course, if you do test the item yourself, what's to say your results will be correct? Really, you need independent validation data.


Not trying to put you down, just trying to wake you up. It would make you a better engineer to either go directly to honda and ask for the information, or test for it yourself

I've now been involved with FSAE for over 4 years, and before that I have worked in the railway industry working as a designer, draughtsman, project manager - working, designing and building everything from carriages to whole railways. Unfortunately, in industry it is often impractical to test everything so you have to use external data supplied by partners, suppliers etc.

There is not enough time to do everything in life - hence why I am collaborating with another university on our engine front.

Out of interest do you have a contact at Honda http://fsae.com/groupee_common/emoticons/icon_wink.gif

[Pete M]

Yeah, i'd say asking for data on an engine is no different than sharing complex CAD models of bought parts or sharing tyre data, etc.

I think it's fair enough to complain when someone asks you to design their car for them but he's not asking that. He just wants some data on something that you didn't design either. I'm sorry, but measuring how much force it takes to change gears does not take a genius and is hardly top secret data. It didn't exactly take us long to do.

But why should he do it if someone else has already done it? If you don't want to give him the data, don't, but just because he's not masochistic enough to want to test every minor little thing himself doesn't make him a bad engineer. If he just goes on a single number some random person gives him and the thing he designs doesn't work as a result... well, that's a different story. But still, that's his decision to make.

For what it's worth, we got numbers similar to Brett Neale but slightly higher, on an F4.

[Brett Neale]

FWIW, our clutch force was 25kg over about 13mm of actuation at the lever.

I don't mind giving out data like this (it's all pretty simple, no point hiding it) as it also serves to verify other data that you may have collected from other sources.