Rohan said:
The bicycle guys report that hi-tensile tubing, if shot-peened and then heat treated, is a lot stiffer than previously.
They say they learned this trick from the motorcycle racing guys ?
I would have to say the bicycle guys are misled,and probably measuring yield strength instead of elasticity.It's a common mis-perception that increased yield affects elasticity.
For all practical purpose,the heat treatment makes no measurable difference to elasticity.Sometimes it can be measured,but it's about 0.5% difference and the higher yield strength can be more elastic (lower Young's modulus).
Extreme cold working/work hardening can make a very small difference to elasticity.
Shot-peening only affects the fatigue life,not the stength or elasticity.
FOR ALL PRACTICAL PURPOSE,ALL STEELS HAVE THE SAME ELASTICITY.Chrome moly is slightly more elastic than plain carbon steel,but the difference is small.Operating temperature has a bigger effect on elasticity than anything.
Paint baking temperatures don't amount to heat treatment.You need to get up around 230 C. before you start reducing the hardness and yield strength,even if a part is very hard to begin with.
The area of the inside diameter of the tube and the outside diameter of the tube both have a bearing on the ability to resist bending and torsional flexing.More accurately,it depends on area squared and the difference between inside and outside values.IT'S NOT ROCKET SCIENCE OR MAGIC.
*For a given weight of tube,increasing the inside and outside diameters will help rigidity.There is a limit to how far you can go with this;the tube will buckle easily if it becomes thin like a beer can.
*For a given outside diameter,decreasing the I.D. which means INCREASING THE WALL THICKNESS AND WEIGHT,will ALWAYS INCREASE RIGIDITY.