jim rozen wrote in message ...
In article , Ed Huntress says.
Actually, a lot of custom bicycles are made with thin-wall 4130 today. If
you really want to see thin-wall tubing on a bicycle, saw through the frame
of an old, high-quality bike made with double-butted Reynolds 531 or
Columbus tubing. They're very darned thin.

In the days you are talking about, the thinner center sections of a
lightweight bike tube were typically 0.032" to 0.028" thick. Time
trial frames would be scarry light, 0.024" or even (Gasp) 0.020".

Now 0.024" and 0.020" can be used for touring frames. 0.016" and
0.015" are used for racing frames. Larger diameters provide adequate
rigidity.

These steels are still 4130, or closely related to it.

True Temper's air hardening OX Platinum has a tensile strength that
exceeds 195,000 psi, before welding. Silver brazing does nothing to
alter this strength, but brass brazing or TIG welding INCREASES this
strength considerably.

Schwinn Paramount track bike - those things were scary to
ride, they were so light.

Jim

My Paramount track bike has 1 speed, no brakes, derailleurs, levers or
cables. It weighs almost 22 lbs. Frame alone is 4.5 lbs.

A friend of mine recently built a lugged, steel, frame for a
cyclocross bike. (Cyclocross; Think off-road racing on 10 speeds) With
cantlever brakes, rear derailler and knobby tires it's a bit under 19
lbs.