Here is a perfect example of why...

I had 33s do this and I increased to 35s I went heavy duty tire carrier after seeing 33s do this.

Some how the bottom curved section probably because it was bent using heat... stayed in tack even though clearly there is less metal to rely on and in the radius of a bend You see how it cracked the 4" section above that was Heat affected zone from welding and not normalizing afterwards...

Steel is what I do so This stuff I understand.

I am currently and have been now a Certified Welding inspector by the American Welding Society of America...

CWI for short. In most weld failures the weakest section of the steel is the base metal directly next to the weld the weld becomes the strongest part of the assembly and the base metal beside the weld the weakest due to the sudden heat input to the steel...to correct this flaw you have to heat up the part above 1400 degrees and then gradually cool it back down to ambient over the course of hours which is called Stress relieving or normalizing the steel Process....