Mounting a bag to a backbone

[DelombardR]

For the five-day trip to Waukesha a few years ago, I mounted one of my 1970s TA handlebar bags on my 56" Expert backbone.  I used a segment of Cinelli handlebar, a strap bolt, and an antenna clamp.  Trying it out on my Light Roadster, I found it scratched the paint and dug into the backbone by the sharp corners of the antenna clamp.

I put two stainless hose clamps around the backbone where the scratches were and tightened them up, but with the screw body to the side of the backbone so that they did not interfere with the tire.

The antenna clamp edges then contact the hose clamps instead of digging into the backbone.

The hose clamps I had were extra long, so clamping onto the backbone temporarily showed how much excess there was.  That excess length was broken off so as to not interfere with the tire.

Rather complicated, but spreads the stresses on the backbone out more.

An idea to pass along - and to ask if anyone sees a problem with doing it this way. I know it's not 'old school' but I don't want a bag to rotate into the wheel.

[Ron Miller]

Here is another approach to mounting a bag on a backbone.
 First photo shows bracket on the back of MIP bag.  I made a dozen MIP bags about 25 years ago. But only 1 of these brackets.
 Second photo shows how top of bag mates with the spring. 
Removal takes about 6 seconds.  Just back off the large knurled Nut then slide the strap out of the wood bar and the bag is in your hands with nothing left on the bike.
Bottom photo shows the bracket removed from the MIP bag.  It is aluminium and Stainless steel.  Mounts in 2 pockets sewn into the back of the bag
It works very well but involves a bit of work to make.