Many new car buyers witness green valve stem caps on all their tires. On enquiring from the dealer they are told that these tires were filled with nitrogen. They will further explain that nitrogen filling will keep your tire temperature and pressure constant preventing the tire from rotting inside. The dealers charge a significant sum for this upgradation. Most of the tire stores and dealerships around are claiming that nitrogen saves a great deal of money on the gas expenses and offers a far better performance than air. But as a car owner it is your right to know the truth. Is this expensive option worth the money spent? Let’s take a look.
Why Nitrogen is recommended?
Most dealers and tire stores recommend the nitrogen filling for modern car’s tires. They feel with nitrogen filling your car will see a drastic improvement in fuel efficiency, handling of the car and extended tire life. All these are achieved by improved fuel economy, good pressure retention and cooler temperatures for the running tires. But let us take an in-depth look at all these benefits.
Fuel Efficiency:
Fuel dealers say that under inflated tires can lower your car’s gas mileage by about 0.3% for each 1psi pressure drop in the four tires. So, the plain theory is: as nitrogen loses its pressure at a much slower rate than air, so you are bound to get correct psi. It will therefore lead to fuel efficiency. But proactive car owners can negate this effect. If you check the tire pressure at least once every month you can use air and still get good fuel efficiency. So, the first benefit is negated. Though, such a practice is easier said than done. Most people either forget to check their tire pressure or do not know how to do it in the first place. Though Tire Pressure Monitoring Systems have become a norm since 2009, but less than 50% of the car owners still do not maintain proper tire pressure. So, it is bound to be a difficult task.
Handling of the Car:
Better tire pressure retention leads to good handling. Everyone knows that a tire will lose pressure as much as it is used. Temperature conditions also accelerate the loss of pressure. Usually there is a loss of about 1psi for a 100C rise in temperature. Leading tire manufacturers feel that nitrogen offers a stable tire pressure as it has larger molecules compared to oxygen. In 2006, there was a test conducted to determine the quantity of air loss for nitrogen and oxygen filled tires. The results suggested that nitrogen reduced the tire pressure loss over a long period of time. The difference in loss between both the varieties was 1.3psi. So, this benefit is true.
Extended Tire Life:
Cooler temperatures for a running tire extend its life. When you fill tires with oxygen it is pressurized and the humidity condenses the air to liquid. The liquid then accumulates on the air storage tank (which is used at the gas stations). When you add compressed air to the tire, the water is released. While driving the tire heats up and changes into gas, which expands thus increasing the tire pressure. As nitrogen is a dry gas there is no liquid released to create pressure fluctuations. But the pressure fluctuation witnessed after using air is not as drastic as mentioned. It is only a negligible amount.
Prevent Tire Rotting:
As mentioned before air creates water which can rot the tire from inside. But most of the modern car owners use alloy wheels which are coated with aluminum, thus forming aluminum oxide and protecting the tires from rotting.
To leverage the true benefits of nitrogen, it has to be 93% pure. This means that you have to add 15% extra nitrogen every time to get rid of the oxygen in your tires. That can be costly. Based on the above findings and the high costs of nitrogen filling it can be said that your expense is definitely not worth it.
