Some cars are even sold with tires that already have those green caps on the tire stem because they automatically come with nitrogen according to Consumer Reports. That said, nitrogen comes at a ...

While they usually go unnoticed until you lose one, tire valve caps do serve an important purpose. But are they universal, ...

Some cars are even sold with tires that already have those green caps on the tire stem because they automatically come with nitrogen, according to Consumer Reports. That said, nitrogen comes at a ...

Green caps on tire valve stems usually mean the tires are filled with nitrogen instead of ordinary air. ... The absence of moisture in dry nitrogen ensures a more steady temperature inside the tire.