The solid pole is just a special case of the hollow pole where the inner diameter, d, is reduced to 0.

**Example 1** - your ‘old’ tube:

A tube of outer diameter D=152.4mm and a wall of 3.98mm will have an inner diam, d=144.44mm...

Putting these numbers into the formula above, should give a max bending moment of

**M**_{Y}=1368kpm before taking a permanent bend, and

M_{B}=1676kpm before breaking

**Example 2 ** - your ‘new pole’,

The outer diameter, D=177.8mm and wall of 3.98mm gives inner diam. d=169.84mm

Putting these numbers into the same formula, should give a max bending moment of

**M**_{Y}=1883kpm before taking a permanent bend, and

M_{B}=2307kpm before breaking.

Now, it is almost midnight here, so I suggest you double-check the numbers.

The reason why my results are more conservative than yours, is probably because another value of material strength, Sigma, has been used.

**Conclusion:** I now think it is better to go for the thickest, ‘new’ pole with M_{Y}=1883kpm (if my calculations are right...)

Cheers,

Arne