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ECONOMY DRIVE
Page 64
Page 65
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Wide single tyres — worth the money or a niche
market? Colin Barnett and Emma Penny investigate.
Goodyear Goodyear's offering for this new market is the Marathon LHD495/45R22.5.The wide LHD will go on sale throughout Europe early next year, with pricing promised to be near comparable with a pair of conventional covers. As you would expect. Goodyear's selling points are essentially the same as Michelin's, although it adds improved braking to the list. Underlining its commitment to gaining the maximum life from its products. it also had a Marathon Super Single on display that been through its Next Tread remoulding process.
An impressive, if not wholly scientific, practical demonstration of some of the benefits of Super Single drive tyres was staged at Goodyear's Mireval proving ground in the Camargue region of southern France. A pair of Volvo FH12s, identical but for the rear tyres, began by accelerating side-by-side up to 45km/h. then coasting from the same marker. The improved rolling resistance of the wide tyres saw that truck coast significantly beyond the one with twin rears.The second test saw both trucks brake from 60km/h on a wet track — this time the difference was about only 1 metre in favour of the Super Single, but who knows what might have been occupying that metre in real life?
Looking to extend the wide drive tyre concept, Goodyear also revealed that it is developing a 355/45x17.5in drive tyre specifically for the 7.5-tonne sector, to accommodate higher cubic capacity bodywork than is currently possible.
Goodyear is not quite as far down the road to tyre pressure monitoring as its French rival. Its answer, being developed in conjunction with VDO Siemens, is the Tyre IQ system. a system fully integrated into truck dashboard displays and expected to be available for OEM fit for the 2007 model year.This will pass data between an independently powered transponder with 3600 antennae and a chassismounted reader.
Another potentially useful product from Goodyear is a tyre with a self-sealing lining around the tread area inside the casing. Still under development, the lining was demonstrated to seal the hole made by a 3min nail passing fully through the casing, even when the nail was removed. Addingjust 3kg to the weight of each tyre, we can expect to see it in service within two years. Before then,2004 should see the introduction of Goodyear's Radio Frequency ID (RFT) embedded identity chip, which will enable tyre life data to be read with a simple hand-held scanner.
Trailers are not forgotten,and while revealing its new product for tractors. Goodyear simultaneously unveiled its Marathon LHT 455/40R22.5 product whose 936nun diameter allows high-cube mega-trailers to run 22.5in wheels and brakes while retaining 3m of interior height within the Continental height limit. Goodyear's glory in this area was slightly stolen by its Dunlop partner's revelation of the same concept on a Schmitz Cargobull trailer at the RAI Show (CM30 October). • "Use 2% less fuel, improve vehicle stability, carry up to 130kg more payload, cut rolling resistance...." the list of benefits put forward by Michelin certainly looks impressive.
However, there's one key point missing for UK operators and that is that legislation means wide singles can be used only on trucks up to 40 tonnes. But Michelin believes the 40tonne restriction is based on out-dated research, and it's hoping to lobby government for a change in legislation which would broaden its market.
According to the company's technical expert, Paul Kendrick, the restriction is based upon research which suggested wide singles caused more road damage. "Research since then has shown that there's now no difference between twins and wide singles -they have the same amount of road contact." And that means they cause an equal amount of road damage hence Michelin's hope of changing government policy.
But it's got wider aims than thatit's hoping to influence truck manufacturers too, asking them to reconsider chassis design on vehicles where it would be appropriate to fit wide singles on the drive axle.
It's already working with MAN on this as it believes fitting its new X-One tyre on the drive axle could allow truck manufacturers to change chassis design, widening the rear axle track by 170mm, which it says would help improve stability and road holding.
Having the manufacturers on side is vital, as Michelin says X-One tyres are available only as a factory option -and not to be retro-fitted. Factory fitting, though, also means it's easy to ensure other vital kit is included where operators choose wide singles; integrated vehicle tyre pressure monitoring ( IVTM) and an electronic stability programme (ESP). IVTM constantly measures tyre I sure, with any abnormal difference in pressure being highlighted on a dashboard-mour display. The system relies on a wh module fitted to each tyre on the tractor and trailer, which sends ret. pressure readings to the central electronic unit via radio transmissi it can detect even very slow preE loss at an early stage, says Michel But where there is a sudden loss c pressure, such as a blowout, the E comes into play, helping to bring tl vehicle to a safe stop. It works by adapting the braking intensity of e wheel, keeping it on course.
So it sounds as if Michelin has gl sorted government politics apar ticked the boxes on fuel consump load weight and safety, but there's small problem remaining the pri( 10% more than a set of twin tyres., while Michelin may defend its pric strategy, arguing that the benefits outweigh the price differential, operators will still be faced with pa more -and that might be a leap of faith too far for Britain's hard press transport industry...