[CR] Dropout Adjustment Screws - Why Do They Thread From Front


Example: Racing:Jacques Boyer

Date: Wed, 3 Feb 2010 00:13:42 -0500
From: Justin Miller <justinkmill@gmail.com>
To: <classicrendezvous@bikelist.org>
Subject: [CR] Dropout Adjustment Screws - Why Do They Thread From Front


Andrew R Stewart <onetenth(AT)earthlink.net> says:

"Justin- Have you not seen drop out adjusting screws with the knurled or wing form on them?"

Yes, and the knurled form often unscrews when turned to the left. This is what prompts me to ask why they thread them this way.

"The idea is two fold. One is to have a nice flat surface to butt up against the axle, like the screw's head allows for."

The knurled pieces on the "rear" of the adjusting screw could be made with a nice flat surface, too, and sometimes are.

"Second is to let the rider be able to move the screw with out a tool."

This only works if the knurled piece is tightened adequately, which it often isn't.

"These screw end cap/nuts often rattle off the screw, and like that PV adapter on the valve, go missing."

This strikes me as another reason to put the knurled/cap nuts on the axle side. If they are butted up against the axle they can't go anywhere. "One of my anilities is to tighten the cap really well when I work on a bike with them."

I would say your precaution is reasonable. But I still don't understand why the screws are threaded from front-to-rear.

Justin Miller
Philadelphia, PA
USA