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Hello and Welcome to Mr.G's blog. Here you will find articles on what I am teaching or making.

Thursday, July 24, 2014

How does a Quick Release Skewer work?

The Quick Release Skewer...  What does it do?  How does it work?  And where did it come from?


Intro:
I needed a starting point... so I went down to my shop and grabbed an example from a wheel hanging on my wall. After removing the skewer from the wheel, I took time to draw it. This particular quick release was made by a company named "Sachs". This is a German company, although mine is labeled "Made in France".  Who is Sachs?  Well, according to Wikipedia, Sachs' story starts way back in 1886!  They made ball bearings, motorcycle engines and bicycles parts.  Put that all together and you have a motorcycle company.  Cool stuff.

Click "read more" to open this blog post...


Soundcloud
Click play on the Soundcloud to get the story and follow along with my drawing and photos below.


On the left is a photo of your typical 26 inch rim.  The photo on the right is of my set up to draw the quick release.  I love the simplicity of this mechanism.  Below is a drawing illustrating the leverage used to move the CAM, which holds the axle in place.


You see, there is a CAM, which is an offset lob, on the lever shaft.  This moves head closer to the drop out, and tightens the axle.  Next, I will take it apart to photo the parts that make it work.


As you can see, there are five parts, well six if you include the nut on the other side of the skewer shaft.  The lever will be our focus.  In the net photo I put a caliper on the CAM that set the movement.


Ok, the measurement on the above is of the lever shaft.  .275 of an inch.
Below is the measurement of CAM.  .351 of an inch.


So, what does all this mean?  Well, if you have a shaft of .275" and a Cam of .351", then you have a off set movement of .076".  That is all it takes to tighten the axle on your bicycle forks.  Next I will measure the overall length of the skewer in the open and closed positions.


In this set of photos, I have measured the length of the skewer in the open and closed positions.  On the left is 5".  On the right, in the closed position, is 4.938".  Not quite the .076" I calculated when measuring the lever shaft directly...  but close.  The point is you can see that the head of the skewer gets closer to the nut on the other side.  This will tighten the axle.  So there you have it.  Still want to learn more?  Lets more into the history, of the Quick Release.  I mean, think about it...  what did bicyclist do before this?  Click play on the "soundcloud" at the top of the blog to hear the story if you did not already.  Thanks for reading.


Feel free to comment or write me an email.  As you may know, I offer classes on bicycle repair, drawing and small engines.  :)


Ron.Grosinger@gmail.com

 My References:
History of the Quick Release Skewer:

History

The mechanism was invented in 1927 by Tullio Campagnolo.
Campagnolo
That is the legend, but what is the real story of Campagnolo?


Campagnolo profile
SRAM owns Sachs Bicycle Components
Turns out that ZF Sachs is a German company.  They might be the oldest motorcycle co
Sachs Motorcycles is a German based motorcycle manufacturer, founded in 1886 in Schweinfurt as Schweinfurter Präzisions-Kugellagerwerke Fichtel & Sachs, formerly known as Fichtel & Sachs, Mannesmann Sachs and later just Sachs.
History of the Sachs Motorcycle (bicycle with motor)



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