Lever Pivots Mechanical advantage ??

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Gary B
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Lever Pivots Mechanical advantage ??

Postby Gary B » Wed Dec 26, 2012 11:08 am

Howdy all,
Here's a question that I'm hoping someone can answer for me.

I have bought several different brands of Levers to suit both Gasser's & Sherco's, But when we change them the clucth quite often will be heavier / lighter.
I've done some measurements and the distance between the pivot hole (for the mountinhg bolt) and the pin hole that works onto the back of the master cylinder can vary by 2 - 4 mm. Does anybody know which brand has the biggest distance here :?: . The bigger the distance between these two points the greater mechanical advantage you will get, so the clutch should be lighter, or you can get more pressure onto the front brake.
I've got AJP levers, Apico levers & V levers. As of yet I haven't bought any S3 levers.
I've attached a picture below for the measurements I'm looking for.

Hoping someone can advise me here.

Thanx in advance & have a Great New Year.

Cheers,
Gary B. 8)
Attachments
Lever 2.jpg


Gary B. from Wollongong MCC.
Now the Old Man in "Team Boniface"
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The Hell Team
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Re: Lever Pivots Mechanical advantage ??

Postby The Hell Team » Wed Dec 26, 2012 12:48 pm

Hi Gary
Yes i have measured all these up about 18 months ago, and seem to remember the shortest ones were about 14mm and most were in the 16-17mm range , with i think the latest Scorpa SR levers having the biggest mechanical advantage.
I'll drag out the info when we go back and let you know.
Do you want drop pin (gg) or straight pin (sherco)?


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Gary B
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Re: Lever Pivots Mechanical advantage ??

Postby Gary B » Wed Dec 26, 2012 5:10 pm

Thanx Paul.
Info on both if ya got it, as you know Team Boniface has a Sherco & Gassers.

Cheers,
Gary B.


Gary B. from Wollongong MCC.
Now the Old Man in "Team Boniface"
:?

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Re: Lever Pivots Mechanical advantage ??

Postby The Hell Team » Thu Dec 27, 2012 7:53 am

Glad I document this stuff, the Scorpa lever had the shortest distance!
Attachments
LeverComp2.jpg
LeverComp1.jpg


We can crate and freight bikes Australia wide for very reasonable rates. Ring or email with your location for freight quote.
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Re: Lever Pivots Mechanical advantage ??

Postby Joe Henderson » Thu Dec 27, 2012 8:18 am

Dear Gary,

Correct me if I am wrong, but I thought that the shorter the distance between the fulcrum and the load meant less force, for a given effect, at the end of the lever ( where your finger operates).

I think that you have go a bit deeper into the geometry to measure and work out the lever ratios for each make of lever. Are they all the same?

It also matters where in it's working arc the lever is positioned.

And don't get me started on linkage rear suspension, Ford Pinto engine rocker arms and swept spreader yacht masts!

Blame Archimedes.

Bloody old men in white robes and beards. They have been interfering with our actions all through history and myth, up to and including the carpenters son who just had a birthday/appropriated pagan festival celebrated.

It's all relative and I hate my relatives.

Regards,

Joe.



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Gary B
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Re: Lever Pivots Mechanical advantage ??

Postby Gary B » Sun Dec 30, 2012 11:58 am

Paul,
Thanx Heaps =D> .
And Joe, your a Bugger, I thought I had something worked out, now Im gunna have to get out the slide rule & put my thinking cap on.
My thinking cap doesn't fit very good at this time of the year. (too much piss & good food) :D

Cheers,
Gary B. 8)


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Now the Old Man in "Team Boniface"
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Steve Holzhauser
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Re: Lever Pivots Mechanical advantage ??

Postby Steve Holzhauser » Sun Dec 30, 2012 1:00 pm

Your on the right track Gary, you are looking for smoother progressive feel which comes with the wider travel of arc, same principal we employed way back of lengthening the actuating arm on the Ty's to give a softer and smoother transition of clutch engagement.




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