I am running a 1.5" .375 wall Tierod from 4x4 Iron in my truck. It is stout as hell. I have smacked it pretty good on rocks and it doesn't even have a hint of a bend in it. I rock crawl so I have hit it a fair number of times sofar with good success.
If you wanted real beef you could get a 3/8" thick tierod like I have and sleeve a piece of 1.75" .120 wall tube on the outside of that making your tierod walls .500" thick. If you bend that you have some real problems.
I was told with the 3/8" tierod like I got that if I ever bent my tierod I would most likely have just broken something else in my steering system or front axle at the same time like a TRE, knuckle, etc.
I am known to drive by brail sometimes and my 3/8" tierod has served me well sofar.
Harley