There has been much talk about the supposed benefits of nitrogen inflation during the course of this year. Some people call it a gimmick, others take the view that the technological benefits are based on science and that the economic benefits are not to be sniffed at. With this in mind Tyres & Accessories addresses the myths surrounding nitrogen inflation.
Nitrogen tyre inflation is more common than you might think. While comprehensive market data is difficult to come by at this relatively early stage in Nitrogen market’s development, the number of systems on the market is definitely in the hundreds. One equipment manufacturer told T&A (rather optimistically) that there are 500 of units currently on the market. If this is correct it is highly unlikely that these units are being used in tyre inflation applications.
Speaking to Pneu-air sales and marketing director, Leigh Stote, revealed some more realistic figures. Pneu-air, the current market leader, reports that 168 of its Uniflate tyre inflation systems are currently in use in the UK. “To our knowledge no other manufacturer has more than four or five systems currently in use,” the marketing director added.
As Nitrogen inflation companies sell their products on the basis of improved performance and economic benefits, it is perhaps surprising to discover that the majority of N2 units are used on passenger cars.
Surely car and commercial vehicle fleets stand to gain the most from this concept? “We do have distributors who have systems with the capacity to inflate truck tyres but we have no feedback on the ratio of HGV to cars. Additionally we have several systems in this country which are dedicated HGV inflation systems based at places such as Borough Councils,” Leigh Stote explained, adding: “I would suggest that anywhere up to 90 per cent of inflations are currently done on standard car tyres.”
However the relatively low-level activities in the fleet market belie the suggestion that the greatest potential for nitrogen in terms of cost savings comes from the truck market. “Whilst individual motorists can extend their tyre life and save on fuel, for any HGV fleet this saving is magnified,” Pneu-air’s marketing director commented. From the company’s point of view the most attractive thing for fleets is a potential two per cent saving on fuel consumption.
One large fleet has already signed up for Nitrogen. “In the last few weeks, we have discussed the introduction of Nitrogen inflation for one of the large supermarket chains, which is set to save millions of pounds purely on fuel consumption,” Leigh Stote reported.
In the retail sector ATS Euromaster has been running a Nitrogen pilot scheme at 25 of its UK outlets since February. The ATS scheme has reportedly been using equipment from three sources – Pneu-air, Parkers and Tyresafety. The vast majority of units for the ongoing trial (20) are provided by Pneu-air. Meanwhile T&A has heard that a number of commercial vehicle fleets and at least one other large retailer are also investing the possibilities of using nitrogen. These trials are said to involve competitors of both ATS and Pneu-air.
O2 or N2?
The biggest benefit that nitrogen inflation offers is more stable inflation pressure. Due to some complicated “ideal gas laws,” the people behind Nitrogen inflation say that N2 does not permeate through rubber as quickly as normal air does. Reading some professional engineering forums however, reveals that this assertion alone is the subject of much discussion. Scientists on both sides of the argument report different interpretations of the available data and question whether foundational concepts like Graham’s law or ideal gas laws even apply.
Formulae like PV=nRT, don’t mean much to most of us, but according to some estimates, oxygen permeates through the wall of a tyre 30 – 40 per cent faster than nitrogen; others say it is as much as 300 per cent. While the US Tire Retread Information Bureau (TRIB) and some manufacturers have made a chart stating “nitrogen is the slowest of all gases to flow through a permeable barrier,” there is little in the way of hard scientific evidence to support either figure. Despite this a truck or bus tyre inflated with nitrogen reportedly takes about three months to lose 2 psi, compared with about 2 psi a month for a normal, well-maintained tyre Nitrogen proponents insist.
Whatever side of the argument you support, it is clear that tyre inflation is probably the single most critical factor for maximising tyre life, and is therefore a good selling point. As TRIB said in its report about the benefits of nitrogen inflation, “properly inflated tyres not only last longer, but also are safer.” The report went on to claim that “cooler running tyres; longer tread life; less oxidation of tyre components, and reduced rim and wheel corrosion” are all the result of using nitrogen as opposed to normal air. Furthermore, “the result is increased tyre life, improved fuel economy, reduced tyre aging and a more durable casing for improved retreadability,” according to TRIB.
The reason the level of oxidation is reduced is because the oxygen in compressed air is replaced with nitrogen. Less oxygen equals less oxidation. Air also contains moisture, so the effect, and therefore the benefits, of this principle are most noticeable in humid countries. High performance applications are also likely to notice the benefits of using ‘pure’ Nitrogen.
Then there are pressure variations caused by temperature. Since air, which contains oxygen, is not an inert gas, it is affected by changes in temperature, which affects the rate of air loss from a tyre. The air inside a tyre expands when heated and contracts when cooled. According to TRIB, the consensus is that for every 10˚F change in temperature, there will be a 1psi change in tyre pressure.
Another supposed benefit of the fact that nitrogen is effectively dry is that it can slow a tyre’s “aging.” According to TRIB, “a reduction in rubber oxidation slows a tyre’s “aging,” improving the casing’s structural durability, lengthening its useful life and yielding a higher proportion of retreadable casings that can survive more retread cycles.”
Support for nitrogen inflation can be found in a number of demanding existing applications. For example Formula One, Indy, Le Mans and NASCAR racecars have been using nitrogen instead of air for some time. Likewise commercial and military aircraft; military vehicles; heavy off-road construction equipment and even space shuttles have all used N2.
The scientific benefits aside, Nitrogen inflation’s greatest strength is its marketing benefits. As Nitrogen inflation units are currently less than common, if a customer wants to re-inflate their tyres they are far more likely to go back to the shop where the tyres came from. Some garages are already making the most of this by offering free or low cost Nitrogen inflation as an incentive along with the purchase of new tyres.
But what’s the damage?
Prices vary from company to company, but Parkers, Tyre Safety, Taray International and JIA Sources and Copco are all known to sell nitrogen at prices roughly ranging between £1000 and £2000. Prices go up to as much as £4000 for commercial vehicle systems. Pneu-air also offers its systems on a rental basis.
When choosing a system, buyers should be aware that not all generators were developed with tyres in mind, Leigh Stote warns. “Many nitrogen systems in the market today are generic nitrogen generators developed for use in general industry. These systems either lack capacity or the flexibility required for tyre inflation,” the marketing director advises.
Pneu-air offers two different models for the passenger market – a budget system designed for small to medium sized tyre shops and a standard high powered system for larger retail outlets and high performance centres.
“The main difference, apart form the amount of Uniflate Nitrogen produced is that the High Power system operates at 14 bar to allow easy seating and inflation of low profile tyres on to tight rims,” says Mr Stote. The budget system is available at £999 or £20 per week rental, whilst the high power system is available at £1,635 or £25 per week rental. A range of high capacity systems for trucks as well as a fully portable and interchangeable system for mobile vans are also available.
Using these figures as a guide, it shouldn’t be too long before you make your money back, according to Pneu-air. “I would suggest that around 30 inflations per week would be easily achievable with a common sell out price of £1.49. Based on these figures, a shop on the rental basis would be looking at earning £1284 per annum net, from the system after the payment of the rental,” explains Mr Stote. In terms of purchase, this means the payback would be around 6 months on the budget system and around 9 months on the high-powered system.
So what’s next for Pneu-air? “Our main developments have been in the introduction of systems including the portable mobile system and research on our 3rd generation system for tyre depots. We continue our development in the Formula 1 industry where we have been exclusive suppliers for well over a decade. We also have several patents in place for the use of Nitrogen in the OTR industry,” Leigh Stote concludes.