Quote:

And still this question is raised.

No, moly is not more rigid than mild steel. The elasticity of all steel alloys is almost identical (Young's modulus: 30 × 10^6 psi).

"I have always heard that moly is twice as light, and twice as strong."
No, moly is not lighter than mild steel, the weight difference is only 1-2% depending on the exact alloy. The reason it's lighter is smaller wall thickness - that's it.
No, moly is not twice as strong, it's about 30% stronger (not stiffer), and that's if properly welded and heat-treated. If the wall thickness is reduced to save weight the strenghs are about equal. You can have more strength with the same weight, the same strength with less weight, or some intermediate.

Re: "they don't want them trying to weld chrome moly with a OX Acetelene torch"
Guess how Reynolds 531 chrome-moly chassis (including Formula 1 back in the day) are built for road racing? That's right - gas brazed with a torch. Read Carroll Smith.

"both these mild steel cages deflected WAY too much for safety"
That's not what did it.



And why do you say its not stiffer, it takes a significantly
greater force to bend it on a bender over the
mild steel?