Originally Posted by dgregory57
I have never had a threaded headset that needed adjustment... is it actually a weakness of threadless that they require occasional adjustment?
The only time I have ever adjusted a threaded headset is when I was repacking the bearings.
Unfortunately, I have. I have an S&S coupled travel bike that the headset loosened on while I was on a business trip and I didn't have a headset wrench. I wound up borrowing a 32 mm open end wrench from the plant where I was working to readjust it.
Since then I have always carried the Park travel headset/pedal wrench Tim describes above. It is a neat tool and very light. But, yes you are correct that this is a very rare problem.
However, if the stem is properly installed and tightened, threadless headsets very rarely need adjustment until they are disassembled intentionally so neither type is at a disadvantage here.