Sunday, October 04, 2009

Inside the brain case

A piece of the skull of this RSX front shifter had fractured and fallen out, revealing a rare glimpse of the brain of a Shimano STI road shifter.  The mountain shifters are fairly easy to open.  The road shifters don't give up their secrets as easily.  My preferred tools have been a large nutcracker, a vise or a four-pound sledge.

Conveniently, I needed to get into this mechanism to remove some especially stubborn earwax.  The congealed grease originally applied in a softer form by the manufacturer had completely prevented the ratchet pawls from operating.  If you zoom in you can see the yellowish glop.  A few minutes picking it out with a sharpened spoke and flushing the shifter with Pro Link returned it to full function.

The second picture shows a flat-bar shifter pod from a fairly recent Specialized Sirrus.  This pod had prematurely earwaxed.  It also contained the carcass of a small insect.  You might be able to make it out at the bottom of the silver disc in the center of the shifter.


Steve A said...

I once started to take my 105 shifter apart to see how it worked. Fortunately common sense set in while it still worked, albeit not QUITE as well as originally. My fingers are not those of a watchmaker...

Steve A said...

Sometimes it is hard to add one and one together to get two. Somehow this post (and comment) were forgotten when my own STI needed attention. Earwax indeed!