Today’s QT is another homegrown one, from Tech Editor Jim Langley. It’s probably safe to say that if Jim didn’t know this, not many people do. Here’s what he wrote:
Thanks to the Professional Bicycle Mechanics Association I recently learned that all these years I’ve been using the wrong screwdriver to turn the limit screws on Japanese derailleurs!
It turns out that there is a Japanese screw standard (who knew?).
It looks a lot like a Phillips screw; however, you may have noticed when adjusting your Shimano derailleurs that the fit of a Phillips driver is a little loose and can slip.
What’s needed is a JIS screwdriver, which fits perfectly. Here’s a link to the one I bought and am now using: http://amzn.to/2v4IVeW
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—John Marsh & The RBR Team
I would assume that the Philips screwdrivers that come with bike tool kits would be the correct one? Any one know for sure?
I have the correct screwdriver in my tool box to adjust my derailleurs. After I have worked on my bike and need to make a couple of adjustments while the bike is under load, I pack the screwdriver in my jersey pocket. I have always wondered why the manufacturers of bicycle mini tools do not have the correct size screwdrivers included with their tools. I have never found a part on my bike that has use for the screwdrivers on those mini tools. Heck, some of them even have a beer bottle opener (?) If there is a mini tool that has a useable screwdriver for derailleurs please let me know.
Great question: I have never seen a mini tool where the Phillips drivers are described as anything other than Phillips, so I suspect mini tools only feature Phillips, not JIS. This kind of makes sense considering there may be Phillips screws on a bike more likely to need adjustment than the JIS limit screws on derailleurs that generally stay put and do not need adjusting on the road.