Photo from a barbell factory. That's a prototype Vaughn barbell shaft being deflected with 1026kg (2262lb) of force.
How barbells get their strength ratings
There are two main measures of strength for barbells in the market today:
The rule of thumb:Quality barbells are going to give you a PSI strength rating for the bar, and cheaper/cruddier barbells are going to give you a pound capacity.How to rate a barbell for pound capacity:
Does this sound scientific?Maybe for medieval England. Of course, we love Game of Thrones as much as the next person, but as a barbell rating methodology, there's a little too much magical thinking for our barbells.There are three main failures with this style of rating:
- Take a barbell
- Put it on a rack
- Load weight on the sleeves
- Take the weight off
- Is the barbell permanently bent? If yes, you done screwed up. If no, congratulations! That's a weight rating you can claim on the barbell!
How to rate a barbell for tensile strength
- Generally, only one sample is tested- only if it fails is another sample tested... also leading to the possibility of numerous tests until a positive is recorded, and used for marketing
- The test in no way reflects real-world usage- people use barbells dynamically, not just loading them in a rack, then unloading them
- Most companies don't even really do the test, they just guess or estimate a weight rating!
This is what we do for all our barbells. It costs more, but the advantages are clear:
- Buy quality steel from a trusted steel mill that has a tensile strength rating already tested and verified
- Heat treat (improves strength) and otherwise fabricate your barbell
- Test samples for tensile strength (this involves destroying the samples in the test, as the test is necessarily destructive)
- Consistent quality from production run to production run
- A better understanding of the stress our barbells as designed to withstand
- Stronger barbells
If "pound rating" is so bad, why is it so prevalent?
It's easy to do, and easy for people to intuitively understand.
If a person looks at a "1000 pound" barbell, they think they know what that means- they can load 1000 pounds on there, right? But since only a few people in the world (ever) could lift that much, a person would never need a stronger bar, right?
Of course, all the above is wrong. A "1000 pound" rating on a barbell is pretty worthless.
However, tensile strength ratings can be complicated, subject to fudging, and difficult to understand.
Continued next week with: what does PSI really mean? Including tensile and yield strength.
If you've enjoyed this, buy one of our (tensile strength rated) barbells maybe?