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CONVERS FACTORS ON 1

31st March 2005, Page 72
31st March 2005
Page 72
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Page 72, 31st March 2005 — CONVERS FACTORS ON 1
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Which of the following most accurately describes the problem?

One size seldom fits all, which is why chassis converters are so useful.

John Dickson-Simpson reports on the companies that specialise

in creating the ideal vehicle for the job.

Chassis converters are handy people to know.They make vehicles suit particular operating conditions, can extend their useful lives and help hard-pressed operators cope with legislative changes.

No wonder dealers and operators love them, but chassis manufacturers can be scornful and even obstructive, not least for the valid reason that conversions can hit sales of new vehicles. But the situation isn't that simple, because manufacturers who don't want to disrupt their production lines to produce one-offs regularly take orders for standard chassis and send them off to specialist converters.

TVAC (The Vehicle Application Centre) at Leyland and Chassis Developments at Leighton Buzzard are among converters that get a lot of work by that route.

Two other factors have swollen the converters' order books. One is the fashion for short-term logistics contracts that leaves a glut of young trucks on the second-hand market —many of these need altering to suit their prospective buyers.The other factor is the slender margins that many operators have to survive on.They have to make the most of their assets, and that often means adapting their vehicles to suit changing business needs, to take advantage of rising weight limits or to cut their VED bills with extra axles or air suspension.

Enforcers cracking down on axle overloads have further encouraged operators to have another axle added, particularly with health and safety regulations reducing manual handling.The consequent surge in the use of tail-lifts and cranes often demands extra or repositioned axles to correct weight distribution and preserve capacity At the same time the demand for maximum payloads and the trend towards loads that are less dense has increased the market for longer bodies. And at £1,20042,000 it's much cheaper to have a chassis extended than to buy a new vehicle.

Long lead times But even when buying a new chassis, long lead times are tempting impatient operators to snap up whatever chassis are in stock and then have them shortened or lengthened to suit their needs.

A busy construction industry has brought a demand for trucks versatile enough to carry plant, boosting the market for beavertail bodies— a speciality of Andover Trailers and King Trailers of Corby. Many are also produced by New-Tec of Newcastle-under Lyme. Extra versatility is provided by 'cheese-wedge' platforms, in which a foldover tapered rear section converts a beavertail back to a full-length deck.

Weight added by a crane is increasingly compensated for by towing a trailer as well as adding an axle. In any case, having a drawbar hitch helps deal with surges in demand by taking advantage of the 44 tonnes now allowed on six-axle drawbar rigs. In some cases drawbars are also required for the extra load N/olurne they provide compared with artics.

Trailer towing fits well with demountable bodies which can boost flexibility and versatility, especially where there are trunk-tolocal transfers of loads to more compact vehicles serving congested and environmentally sensitive areas. Arising from this, Britain's big specialist in demountable-body systems, Ray Smith Group of Peterborough, has become favoured as a fitter of drawbar hitches. Most converters have also added trailertowing hitches to their portfolios Conversions are not restricted to HGVs, of course: there's a roaring trade in extending light vehicles, adding axles and fitting rear air suspension.

With extra legislative restrictions on driving licence qualifications and speed limits, the demand grows either for downplating to 3.5 tonnes, or for upplating on the basis that if licensing restrictions are unavoidable you might as well make the best of it by carrying a heavier load, TVAC also reports increasing demand for low-slung chassis conversions of front-wheeldrive 3,5-tonners using a light tandem-axle rear bogie. A similar arrangement has been devised by Chassis Developments for rearwheel-drive 3.5-tonners; it has also come up with an ingenious hinged double chassis for car transport. Push-button hydraulics can make the chassis arch so the deck slopes to wheel a car on or oft This is a niche market, but operators in other sectors are being attracted by the idea of a six-wheeled Transit.

A large proportion of light-vehicle conversions involve ambulances, recovery vehicles, minibuses and mobile caravans,but here too,freight carriers are seeing operational advantages in big, low-floor vans with virtual walk-in access.

Judging by the work in progress at the converters, the annual throughput of truck chassis extensions and axle moves/additions seems to be about 1.700: light vehicle conversions boosts that figure to something like 6,000 a year.

The most popular conversions at any given time depend on legislative and commercial pressures. With trucks the big market is currently in converting tractors into rigids — most commonly tag-axle and mid-axle sixwheelers, but lately eight-wheelers too.

continued appeal for articulated operation can be limited, especially if their power falls short of heightened expectations — but what's short for articulated work at up to 44 tonnes can be

As tractors come off contracts their

plenty for duties as a rigid. Added to this is a demand for rigids powered by big, long-life, engines.

David Stubbs of Euro-Axles and Gerald Goodridge of Ne w-Tec both report that tractor-to-rigid conversions currently account for nearly 90% of their business. Their typical charge for a tractor-to-rigid-six conversion is between £6,000 and £6,500 (much depends on how much additional propshafting is involved).

That their shops are full must owe much to their keen prices,which are something like £3,000 below those of competitors with the overheads of big premises covering a wider range of conversions and incorporating refinements such as speed-monitored automatic lowering of liftable axles according to drive-axle load.

Steady income Prudently, several converters assure steady income by developing an extended range of services. Euro-Axles, for example,has a bodybuilding department at Newcastle-underLyme, In Wheelbase Engineering's new 42bay workshop at Darwen they make trailers, demountable body systems and elevating floor assemblies for big vans — and fit tail-lifts.

TVAC offers pre-delivery equipment and inspections, notably for Daf customers; fits the mid axles on Seddon refuse-collector chassis; adds axles for Mercedes-Benz; and creates many special-purpose vehicles. Examples include dual-control Renaults with a crawler auxiliary gearbox for road marking:a drop-frame mobile library with frontwheel drive courtesy of the fore part of a four-wheel-drive Iveco;incident-support units for fire and police forces; and air suspension for ambulances.

At Chassis Developments they &Telma retarders; make drop-frame chassis;straighten chassis; repair accident damage; install power generators; and create mobile exhibition units and health-check units. There's also a lot of demand for fitting and calibrating tachographs,speed limiters and fuel-consumption meters.

The workshops at Chassis Developments and Wheelbase Engineering have big painting booths with baking ovens.

All the well-known converters (they regularly advertise in the classified section of Commercial Motor) are professional engineers.The pride they take in their work is typified by Wheelbasechairman John Pickles:"Look at these frame extensions. You can't see the joint. When we insert a section of sidemember its corner-radius exactly matches the original. So does the steel spec."

No reputable converter relies on the welded joint. The real strength comes from an inserted channel that makes the bridge, whether bolted or Huckbolted. As tractors generally have a chassis about 250mm deep it would deflect too much, even though it would be unlikely to fail. So the original chassis is usually sleeved with 300mm-deep pressed channels, braced by almost full-depth crossmembers. Lift-axle conversions, especially the shorter chassis that venture onto rough terrain (often on agricultural work or as concrete mixers) have doubled-up sidemembers.

The 'road friendly' air suspension which is required at the maximum legal weight has also simplified the fitting of extra axles.Almost all the converters favour Granning running gear, although TVAC favours Gigant.

After completion, all conversions have their brakes tuned to comply with the EU Directives and the type approval standards that apply to new vehicles.The consequent bureaucracy is an involved process, but consultancies can be a huge help.The Granning organisation, for example, is admired for its back-up with approvals.

The level of co-operation from the original manufacturer varies; Mercedes-Benz and Scania are said to be particularly helpful. Even compatibility with electronic braking systems poses no problems with Mercedes-Benz, but all the others are reficent.This could become more of an obstacle as tractors with electronically controlled braking become candidates for conversion. However, any misgivings among the manufacturers' engineers are unlikely to have any lasting foundation on safety grounds: specialists like Granning and SvTech (Specialist Vehicle Technology, at Leyland) seem well on top of the situation.

SvTech's £250 solution is an electronic box that applies an added axle's brakes independently of the chassis' original electronic system.

A tug of war on this issue is looming between the truck manufacturers' engineering and commercial teams, but ultimately market forces are bound to prevail." We've converted over 200 Dafs in the past three years," says Gerald Goodridge of New-Tee. "Are the usedvehicle departments going to say goodbye to so many sales?" •


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