Using nitrogen in your motorcycle tires

Nitrogen vs. air—which is better for your bike?

Added December 11, 2018

Using nitrogen instead of plain old air to fill motorcycle tires is a topic of interest among many motorcycle riders. As nitrogen generators become more affordable, the use of it in tires will become more widespread. So why use nitrogen in motorcycle tires? Are the benefits worth the cost?

Nitrogen vs. air

We’ve been filling our tires with air since the beginning of pneumatic tires. Here’s what air is composed of:

78% nitrogen
21% oxygen
1% water vapor and other trace gases

So, nitrogen is already in your tires when they are inflated with simple air. When filling tires with nitrogen, the amount of nitrogen in them is increased to an average of 93%–95%.

Why more nitrogen?

The primary reason for using a higher concentration of nitrogen has to do with the size of its molecule. Nitrogen is a larger molecule than oxygen, the other main component in air. Tires on rims tend to lose pressure over time and smaller molecules migrate out faster. That means tires filled with a higher concentration of nitrogen will maintain their pressure longer than tires inflated with air.

What’s wrong with air?

The big negative with air is the 1% water vapor. Water vapor in a cold tire condenses into a liquid, reducing tire pressure. When the tire heats up during a ride, the liquid evaporates, increasing inflation pressure. Water and oxygen also cause corrosion, but that’s not why nitrogen has become popular—consistent inflation pressure over time is the big difference.

Cost benefit ratio

Filling new tires with nitrogen adds to their replacement cost. This should go down over time as the technology spreads. Since the cost of a nitrogen generator is several thousand dollars, it’s unlikely you’ll be able to afford to add nitrogen to your tires at home.

Correct tire inflation is critical

Whether it’s nitrogen or air, correct tire inflation is critical to maintaining the proper and safe handling of your motorcycle. Proper inflation also results in better fuel economy and extends the life of your tires.

Motorcycle tire inflation is so critical, tires should be checked before every ride. But checking tire pressure releases a small amount of gas from the tire, so daily pressure checks require adding something back. Adding air to nitrogen-filled tires will reduce the percentage of nitrogen, but it’s better to have correct inflation with air than underinflation with nitrogen.

So, is nitrogen worth the extra cost of new tires? The choice is yours. But correct tire inflation is priceless.