Comparing 1 5/8" x .118" MS vs 1 5/8" x.083" CM...

In that diameter and wall thk. the CM is 29% lighter then the MS.

However in a bending moment situation the CM see's 37% more stress then the MS because of the wall thickness difference.

Yes CM is stronger then MS as a material, but concider when putting a much thinner wall thickness on the CM, it takes away all it's material strengh advantages.

So looking at bending. If you take MS and CM at the sizes listed above. A simple case putting 1000 lbs on a cantilevered 10" beam, the MS would bend .111" while the thinner CM would bend .171"

That's over 50% more bending deflection on the CM!

Remember it's not all about the material strength, the wall thickness of the tube has a lot to do with it...