When to replace the hitch pin?
The pin for holding the hitch into the receiver is the only real thing holding our trailers to our trucks. Mine is new, but it got me thinking, how often should it be replaced?
Forum Discussion
swimmer_spe wrote:valhalla360 wrote:mosseater wrote:
Any idea what the shear forces required to chop it in two? There are anomalies in this world but betting the farm very few ever are sheared. The receiver welds would probably fail before that pin would shear. I'd sooner keep the one I have road tested than risk a new one these days.
5/8inch pin has a cross sectional area of around 0.30in^2.
It will depend on the specific steel but say we made one of iron (not steel for a worst case scenario). Iron has a shear strength of around 26,000PSI.
So each end of the pin would have a strength of around 7,800 but since both ends would have to shear to get a failure, 15,600lb.
A descent quality steel (nothing exotic) can be twice that shear strength.
Keep in mind, when you tow, you aren't lifting the weight of the trailer. The force needed to pull the trailer is a small fraction of the trailer weight. Even in a panic stop, the trailer would push the truck into a skid long before the force reached the weight of the trailer.
So long as there is no sign of damage or deformation, it should be fine.
Thank you for the math.
Now, what about fatigue? If you bought it brand new and it is used regularly and is 10,20+ years old?
A. His “math” ain’t right for STEEL, which all hitch pins are made of. And a “decent quality” steel is far more than double the shear value of cast iron.
B. “Fatigue” isn’t a real world consideration unless you could somehow get enough stress into it to have repeated elastic deformation (you can’t and won’t) resulting in strain hardening which will eventually leading to cracking.
However plastic deformation would cause it to be rendered unsafe. Never gonna happen with a proper hitch setup but somewhat common when those silly hitch stinger reducers are used on larger receivers to fit smaller stingers.
Finally physical wear could cause it to have reduces strength. For steel rigging subject to cross sectional loss due to wear, the criteria is a reduction of 10% or more of the effective cross section.
At the end of the day, unless you bend a pin as I described above, there is a 99.9999% chance that pin will outlast you, and your kids too. Maybe grandkids as well.
