Introduction
Nitrogen inflation of tyres has been common for tyres fitted on race cars such as F1, as well as aircraft, trucks and vehicles used in mining and other industrial applications for a long time. Nitrogen gas is also used in Tour de France bike tyres, in all the space shuttle tyres and even the moon buggy had nitrogen in its tyres.
Planes fly at heights where temperatures may be as low as -40C. Any moisture in the tyres can freeze causing vibration and balance problems when landing. Pure nitrogen is dry so eliminates this problem (as would dried compressed air).
In motor sport the smallest fraction of a second can make the difference between winning and losing. Filling with nitrogen can reduce tyre pressure variation caused by changes in tyre temperature. It is also the biggest molecule gas, so it is the slowest gas to migrate through a tyre, and there is therefore very little loss of pressure.
Summary of Nitrogen Benefits
Nitrogen tire inflation has significant benefits over air inflation, and is undoubtedly the best maintenance strategy. There are three main benefits:
• Maintaining correct inflation pressures;
• Extending tire tread and casing life; and
• Reducing tire failure rates.
Correct inflation pressures are maintained due to the much slower rate of Nitrogen dissolution into tire rubber. This finding has been proven through
extensive laboratory and field testing. Reduced tire failure rates were demonstrated during a field trial conducted over 12,000,000 km (7,500,000
miles). The purpose of this paper is to explain the mechanism of extended tread wear. This is a key finding which helps to dramatically lower the operating cost per km for long haul trucking fleets.
The mechanism that directly impacts tread wear is oxidation of the tire rubber. Oxidation in tire rubber is very similar to oxidation of unsaturated fats in
packaged foods. In the food industry, many products that have a food-oil component are packaged in Nitrogen. Ground coffee, peanuts, salty snacks (e.g.
potato chips), creamy pasta sauces, butter pats, cooking oils, and sandwiches are packaged in Nitrogen to extend shelf life and preserve the taste of the product. In normal air, Oxygen is the culprit because it attacks double chemical bonds in unsaturated fats. When Oxygen breaks down these double bonds, the taste of the product is degraded. Stale peanuts taste stale because Oxygen has
attacked the peanut oil. Foods packaged with Nitrogen last longer, taste better, and increase profits for their manufacturers by reducing scrap. Tires also have
unsaturated bonds in the rubber, and Oxygen attacks and breaks down these bonds. Nitrogen inflation virtually eliminates oxidative aging in tires, and this
results in big cost savings for fleets.
Maintenance of Correct Tire Inflation
At a spot price of 90 cents a litre, that is a total fuel bill of almost $44,100,000.00 a year. 2% loss in efficiency is equal to almost $882,000.00 excess costs per year, every year. Tires inflated with Nitrogen maintain correct inflation pressure longer than air inflated tires – up to five times longer.This reduces rolling resistance of the tire and reduces fuel consumption. This means that these lost costs are recouped and drop to the firm’s bottom line as pure profit. Also, when correct tire
pressure is maintained, the tread lasts as long as the manufacturers intend. Under-inflated tires wear faster.
22 Extending Casing Life.Just like the food industry’s experience, Nitrogen can actually extend tire and
casing life and can reduce the number of tire failures in service, by reducing oxidative aging of the rubber. Nitrogen inflation not only extends tread wear and
casing life, it reduces the casing failure rate. Tests on new and retreaded casings show that the rate of failure for Nitrogen-inflated tires is 50% lower than
for air-inflated tires. For a large fleet this saving alone can pay for an entire program. Please note that Nitrogen will not turn tires into Kryptonite –failures on
the road will still occur. However, failures will drop substantially, saving the cost of replacement tires, and unscheduled roadside repair costs, which can be quite
unreasonable at times.33 Simpler maintenance due to elimination of condensed water in tires A lot of compressed air is wet. Water causes rim rust, and can cause chronic leaks through the valve stem. Rust also gets pushed under the bead of the tire, creating micro leak paths. In winter, if a tire needs to be aired down, moisture in the tire casing can freeze in the valve stem. Since Nitrogen is a dry gas, all these maintenance problems are eliminated.
Summary of Fleet Maintenance Savings
Fleet maintenance managers are increasingly turning to Nitrogen tire inflation to reduce their operating costs and increase their fleet up time. Direct and indirect
savings to fleets are:
• Fewer tire failures in service
• Lower costs per km in service for steering tires, drive tires, and trailer tires
• Fewer scrap casings (by allowing additional retreads)
• Higher casing value for resale
• Lower retreading costs
• Lower fuel costs due to proper inflation
• Lower tire costs due to proper inflation when running
• Reduced roadside service calls
• Reduced late delivery charges (for guaranteed delivery services)
• Less lost revenue due to breakdowns
• Lower accident liability due to fewer blowouts and collateral accident claims
• Reduced spare tire inventories
The air we breathe is 78 per cent nitrogen and 21 per cent oxygen. Nitrogen gas is non-combustible, non-flammable, non-corrosive in pure form and environmentally friendly. Nitrogen tyre gas does not attack or oxidise the rubber of the tyre from the inside like air does. It is a pure gas, so it does not hold heat and the tyres run cooler.