The CDC trailer had a flat tire last week, and I found out that it's due to a dry-rot tire stem. This stem was installed in March 2007 (not very old).
I found that the National Highway Traffic Safety Administration has issued a safety recall on Dill tire stems. I talked to the investigator (Chris Lash), and he inspected my tire stem. My stem does not fall in the current recall. My stem was made by EHA (as marked on the stem cap).
For more information, check out the NHTSA Public documents at the link below:
http://www-odi.nhtsa.dot.gov/defects/
select DEFECT INVESTIGATIONS
use PE08036
If you have one tire leaking air at the stem, there's a good chance the other tires will do the same shortly.
After I get my trailer tire done, I'll re-install the tire and bring my spare with the remaining tire for new stems.
If you have a leaky tire stem, you may want to have all the stems replace. Also if you can, save the tire stem and contact Chris Lash at 202-366-2370.
Ed Chan
Leaking Tire Stem
Re: Leaking Tire Stem
Here's the update...
I got a new tire stem and brought the old one to Chris. Turns out the EHA stem was made by Dill and a defective stem. To add insult to injury, the new tire stem is also made by Dill.
A few years ago, most of the material in the stem was made with a super strong synthetic plastic, EPDM. Now all the manufacturers (e.g. China) are mixing more and more rubber with less and less EPDM, which seems to be causing a lot of problems. To make the long story short, I search on the net and haven't found a EPDM tire stem still made.
The closest I can find is a steel tire stem with a flat rubber gommet. At least the gomment is in compression and required to withstand a bending force. I asked Chris about these steel stems. He laughed and said, "You know those are made in China too." He's already got one complaint from a person that used some steel stems and the metal on the cap was different (he may have switch caps) causing galvantic corrosion. When the owner tried to put air in the tire, the cap was stuck on the threads. Instead of unscrewing the cap, the owner sheared off the stem (remember we're talking about Chinese quality metal here).
I think I'm going to order the metal stems for the trailer from Summit
http://store.summitracing.com/partdetai ... toview=sku
Then use PLASTIC caps to be extra safe.
I got a new tire stem and brought the old one to Chris. Turns out the EHA stem was made by Dill and a defective stem. To add insult to injury, the new tire stem is also made by Dill.
A few years ago, most of the material in the stem was made with a super strong synthetic plastic, EPDM. Now all the manufacturers (e.g. China) are mixing more and more rubber with less and less EPDM, which seems to be causing a lot of problems. To make the long story short, I search on the net and haven't found a EPDM tire stem still made.
The closest I can find is a steel tire stem with a flat rubber gommet. At least the gomment is in compression and required to withstand a bending force. I asked Chris about these steel stems. He laughed and said, "You know those are made in China too." He's already got one complaint from a person that used some steel stems and the metal on the cap was different (he may have switch caps) causing galvantic corrosion. When the owner tried to put air in the tire, the cap was stuck on the threads. Instead of unscrewing the cap, the owner sheared off the stem (remember we're talking about Chinese quality metal here).
I think I'm going to order the metal stems for the trailer from Summit
http://store.summitracing.com/partdetai ... toview=sku
Then use PLASTIC caps to be extra safe.