Tires carry a lot of weight and experience significant stress on a regular basis without getting deflated every now and then.
So, if you’re researching how tires maintain their internal pressure, you may be wondering – what is a tire valve? Keep reading to learn everything I’ve found out about this topic!
What Is A Tire Valve?
Tire valves are located on the rim of every tire and are responsible for maintaining the pressure inside the tire, and are also used to inflate a tire through an external air pump. Most commercial vehicles use Schrader valves that use spring-loaded cores while vehicles with thin tires use Presta valves.
If you want to learn more about the types of tire valves available, how tire valves work, how much they cost and more, keep reading for more facts!
What Types Of Tire Valves Are There?
Most commercial vehicles in the world, including cars, light trucks, wide-rimmed motorcycles and bikes use Schrader valves.
Schrader valves consist of an outer stem through which the valve core is threaded, and a cap is screwed on the top to guard the inner core from contaminants like dirt and grease.
The valve core is primarily a poppet valve assisted by a spring which has a small rubber seal at its top to prevent the inside air from leaking through the threads.
However, note that several vehicles with thin tires (such as racing and mountain bikes) use another type of valve called the Presta valve.
These valves have a smaller diameter than Schrader valves which allows them to fit easily into thinner rims. Additionally, these valves are always screwed shut with a cap to prevent any air from leaking out of the tire.
How Does A Tire Valve Work?
Schrader valves contain a center pin in their core which is spring-loaded and acts as a check valve (i.e. it only allows flow in one direction).
To inflate a tire via a Schrader valve, the pressurized external source must exert force on the center pin and push it down to allow air to pass through.
Once the pressure inside the tire reaches the pressure of the external source, the center pin pops up again, shutting the valve and allowing no more air to enter the tire.
Although Presta valves work on a similar principle, you must first unscrew the cap on top of a Presta valve to inflate the tire.
Note that Presta valves cannot be operated with any external pressure source, rather, they need a special adapter to be used with common air pumps available at gas stations and similar locations.
What Causes A Tire Valve Stem To Go Bad?
Valve stems tend to wear out and go bad over time due to excessive use, frequent dislocation, and exposure to heat and contaminants such as dirt and grease.
As well, valve stems can also corrode away if they are constantly exposed to chemicals such as road salts.
How Do You Know If Your Tire Valve Has Gone Bad?
A bad tire valve will continuously leak air pressure through the base or body of the valve. Therefore, to check for this leak, inflate your tires to the recommended pressure and pour a mixture of dishwashing liquid and water on and around the valve stem.
If you notice bubbles forming near the valve stem, then this is a clear indication that your tire valve has gone bad.
How Much Does It Cost To Replace A Valve Stem On A Tire?
If your valve stem has gone bad, you can easily get it replaced from any nearby mechanic or automobile service center for around $30.
In fact, note that valve stems are available for around $10 each, so you can even replace it yourself if you have experience of working with tires.
How Can You Replace A Tire Valve Yourself?
In earlier years, replacing a faulty tire valve used to involve dismounting the tire from the vehicle and taking the rubber off to change the valve.
However, you can now use a Quick Valve Change Tool (available in most automobile stores and online stores like Amazon) to replace a valve without removing the tire from the vehicle.
Listed below are the steps you should follow to replace a tire valve:
- Use the quick valve change tool to remove the valve core and allow the tire to deflate
- Use pry bars to gently push the bead away from the rim to expose the base of the valve
- Use the quick valve change tool to remove the entire valve stem by breaking it off from the base
- Insert a new tire valve from inside the bead so that its body sticks out of the rim
- Use an air pump to inflate the tire through the new valve until the bead snaps into place and you reach the recommended pressure
In case you face any difficulties in inflating the tire before the bead attaches with the rim, remove the valve core and inflate the tire directly at high pressure.
Afterward, once the bead is back in place, you can re-attach the valve core into the stem and bring the inflation pressure to the recommended level.
How Long Do Tire Valve Stems Last?
If you’re careful while operating your tire valve and clean it regularly, you can expect your valve stems to last as long as 5 to 6 years.
However, keep in mind that you should replace tire valves after 6 years, because they will eventually start leaking and have potential to cause problems on the road.
To learn more about tires, you can also see our posts on whether or not you can you drive without a tire valve cap, air leaking from valve stem base, how to remove plastic cap stuck on a tire valve, and tire leaking air around the rim.
Conclusion
Tire valves are used in both tubed and tubeless tires to prevent air pressure from leaking out and are the single point through which tires are inflated.
Most vehicles in the world use Schrader valves that work based on a poppet mechanism whereas bikes with thinner rims use Presta valves that have a smaller diameter.