wrote

Hadn't really thought of it... but you CAN use O/A on a bicycle
frame. The swaged fittings you mention are available as a kit, by the
way. They are normally secured via brazing. This allows you to use
very thin-walled tubing, resulting in excellent strength-to-weight for
the finished frame. Motorsickles typically require heavier walled
tubing and are almost always welded directly, typically with MIG. But
if you take a close look at low-cost import bicycles you can see they
tend to use heavier-walled tubing & MIG. (Just lift one. Big
difference between a 'Red Dawn' and a custom-built bike (bicycle).)
Yep, and they get lighter all the time.

I remember back in about 1973, I bought a Peugeot, UO-8, I think was the
model.

At the time, it was around 27 pounds, and considered to be pretty light.

Now, that's a tank, compared to the new models.
--
Jim in NC