R2D2 wrote:
...
Because the air-hardened joints Increase in strength after welding, the
overall stiffness of the frame is increased substantially (30% greater
than 4130 Chrome-Moly is typical). I'm talking about a built frame here,
not raw tubes. This is of course due to the fact that the 4130 joints
will become annealed during the joining process. Now some may argue that
the ride of a frame built with un-heat treated steel is much more
forgiving (softer), and thus preferable.

The increase in strength at the joints will not effect elastic modulus
significantly. You are confusing two different things here. It would
take precision equipment to measure the difference in elastic modulus
between Reynolds 853 (before or after heat treatment) and 4130 Cro-Moly.
In practical terms there is no difference.

I'm not saying that an 853 frame is ultra-stiff by any means. My
aluminum DF Klein MTB would be considered ultra-stiff. Klein heat treats
the entire frame post welding. The energy transfer from pedal to wheel
is simply amazing.

This has to do with the size and wall thickness of the tubing and the
frame geometry - heat treating the frame after welding affects tensile
strength but not elastic modulus.

Jim's advice here pertains to un-heat treated tubes (like the 4130s),
and not the heat-treated 853....

Jim is correct about there being no appreciable difference in the
elastic modulus of the two steels.

Tom Sherman - Quad Cities USA (Illinois side)