Originally Posted by
tommymc
Check out the Ortlieb Ultimate bags. The mount stands off of the stem and bars enough for cables, I've used mine with a cantilever brake hanger. The lockable bag comes off in an instant. The biggest drawback is the mount's cable fastening system that's not quick to remove and install again.
I have a mount on each bike that I use the Ortlieb with, and leave them there. (Kind of like a wired speedometer/odometer.) The Ortlieb is a bit on the large side for the things I want to take along on every ride, but it'll also hold a jacket and warmers when the weather's uncertain.
I've also got the Thorn auxiliary stem Tourist mentioned on one bike. If I were going to remove and replace, I'd consider removing that second stem with the mount still on it.