It has been said, "The devil is in the details."   Years ago AGCO began testing different brands of valve stems.  We quickly learned there was a huge difference.  When questioned if their stems met Society of Automotive Engineers (SAE) standard 1205-1206 most manufacturers simply could not provide an answer.

This is shocking as SAE 1205-1206 is the industry standard with regard to valve stem resistance to ozone and dry rot

After an exhaustive search, we finally located a company in Germany that could provide documentation of compliance with SAE 1205-1206.  We have bought valve stems from this company ever since.  Other than the obvious safety benefit, these stem hold air better than any other brands we tested.  Holding pressure means client's tires stay inflated, which means our tires last longer.  This results in satisfied clients that buy more tires.  

Contrast this approach with a company buying on price.  They might shop for the least expensive stem they can find. They may save a few dimes, but what can it cost them? This is what many apparently did and with disastrous results.

Dill, a large tire stem distributor, imports stems made by a company in Shanghai, China.  Stems sold in the U.S. from November 2006 through July 2007 were substandard. They did not meet the ozone resistance levels rubber needs to resist cracking. Failure of the stems has already been blamed for at least one fatal accident.

If you purchased tires after November 2006, ask the tire dealer what brand of stems they use. It’s always been good idea to inspect valve stems whenever air pressure is checked.  Now it is even more important than ever.   An easy way to inspect the stem is to simply push it sideways and check for cracks.

If any stem shows signs of cracking, all four should be replaced.

Substandard valve stems are very dangerous.  Like any substandard part the actual cost far exceeds any potential savings.  AGCO, do it right, do it once, the cost is always less.