For most motorcyclists, though, the benefits are diluted. Besides being more expensive than air, nitrogen isn’t as widely available. If you check tire pressures regularly for commuting or pleasure riding, you’ll let out a whiff of whatever is in the tire, eventually requiring a fill-up. Likewise if you adjust your tire pressures for two-up riding or a trackday. Both require a supply of pure nitrogen or you’ll dilute your tires with nasty old air, which, by the way, is 78 percent nitrogen anyway.