# what does green valve stem caps indicate??



## shanksyamaha

My trailer has green valve stem caps on all 4 tires, does that indicate that the tires are filled with something other than just air??? Can I check the pressure and add air to them if needed???


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## bobrussell

they mean the tires are filled with nitrogen. yes you can check the pressure and just add air if you want. IMO, you won't see any anvantage in the nitrogen.


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## shanksyamaha

Is it possible to add nitrogen if needed?? if so who has it??


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## bobrussell

yep, most tire stores/dealers have it. if you bought the tires from them, they'll usually do it for free.


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## shanksyamaha

I think I'll just top them off with regular air. It'll be alot easier. I know theres no one within 40 miles of our town that would have nitrogen and Im getting ready to head to Florida in two days..


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## artmart

The caps can be used with any air or nitrogen you put in your tires. If the tires had nitrogen you wouldn't be losing air, so bobrussel's comment about the advantage is pretty correct (the advantage is not as good as we'd like).

The caps can be used on any tire. If you see green DON'T do anything. It's only when you see red that you need to fill the tires. These caps give you an immediate indication when you need air, instead of having to use a gauge - their advantage is that a gauge can cause air loss when taking your measurement and these caps eliminate that inconvenience.

You will need to know what the rating on the cap is supposed to be so that when you NEED air you won't overfill. There are different caps for different tires and hopefully you have a properly rated cap.

You can mix air and nitrogen-enhanced air. Just know that as the ratio of regular air rises, you'll lose more air over time which is what nitrogen helps prevent.

Until Nitrogen is more readily available and free, I'll keep using regular air.


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## rksolid

The valve stems covers (caps ) are just that, there is no indication of tire pressure. Instead of the typical black cap on valve stem his are green. The green stems ussually indiactes thet the tire was filled with nitrogen. Most people will just top off with air if pressure is low becuase it is free and can be found at most gas stations. The ones Artmart is talking about are clear colored stems with a green indicator for normal pressure and red for when tire is low.


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## Admin

Something like these right?










Product example found here:
TireCheck Tire Pressure Valve Stem Caps - KLE44444

As others said, the green coloured caps usually indicate that nitrogen was used.


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## artmart

That's what I was referring to, but I misundertood that the OP was referring to standard plastic screw-on valve caps that happen to be green in color instead of black.

These caps denote the tires are filled with nitrogen. The desire would be to refill them at a place that has nitrogen, but it certainly isn't required or readily available.

The plastic ones with the indicator are different in that they give a visual indicator using a preset psi of when the tires are low whether you use nitrogen or plain air in the tires.


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