Metal caps

Prevent dirt build up that could cause the valve to open and let air out..???

 

Well come on guys. Why do you think??

Oh I dont know maybe because in a class 8 truck application the cheap plastic caps dont hold up?? Heck they are hardly any good on a bicycle let alone a truck logging 100,000 miles a year. It's simple , the SS caps are meant for the task at hand. Heat dont bother them and the threads dont strip out ..
Ever buy a new rim from accuride or alcoa,? You wont see those ever with cheasy plastic valve caps . And why would anyone want to use anything else.

 

There are two reasons I can think of:

1. To hold the air in case the valve stem malfunctions.
2. To keep out sand, snow, etc.

These metal valve caps should have a rubber ring inside that creates an airtight seal. Valve stems will go out eventually. If you don’t have an airtight valve cap, your tire will deflate and either blow up (while driving) or become damaged, requiring replacement. These metal valve caps need to be retightened every 2 months as driving vibrations will loosen them up.

 

Our drivers are supposed to “retighten” then everyday when the stick their tires. It doesn’t happen but their supposed to!!!

 

Check tire pressure? Ain't nobody got time fo' dat!

 

I tried retightening valve caps every month, but it turns out mine didn’t need it. It also has to do with how tight you can tighten them, and if you can fit your hand in between the tires to do so. I’m an average height guy, and I have never been overweight (by BMI charts). This helps me fit my hand in between the tires to tighten my valve caps well. Big guys or tall guys may have a hard time doing this, unfortunately.

Drivers need to know that every time you check your tires with a gauge, you are supposed to rub your finger over the valve stem or flow-thru valve cap to make sure it’s not leaking. It’s actually common for some valve stems to leak right after checking them with a guage. Sometimes they don’t close fully due to sand, snow, etc. Other times, the valve stems are too old or damaged.

 

Plastic ones only keep the dirt out. Metal ones also keep the air in.