I f fleet engineers had to decide on a motto it
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would probably be"Necessity is the mother of invention". Necessity; in the case of Swift Transport Services, meant achieving a 2.9m side access—standard throughout the 32.5tonne fleet—on a 38-tonner. And invention meant finding a way to keep within the 4.2m height limit that comes with 38-tonnes and five axles.
Push the floor down and the first thing you hit are the tyres. Enter German tyre maker Continental. Its latest HD75/HS45 295/60 R22.5 low-profile range, combined with some innovative input from Montracon, Rubery Owen-Rockwell, VBG and Volvo, gave Swift a full-length trailer deck height of just 1,230mm (48.4in).
We explained how this trick was achieved in a recent Engineer's Notebook (CM 18-24 March) and now we have been able to drive it. The modified FLIO is fulfilling two roles.The 29m side access fits in with Swift's four
axle/32.5-tonne high-cube operation. And the five axles/4.2m height gear the Volvo to Swift's weight-dependent 38-tonne business.
The really clever bit is that both tractor and trailer can be coupled to any standard vehicle—and its all done on good old fashioned 22.5in wheels.
Volvo launched t UK-spec low-fifth-wheel height tractor range last year (CM 12-18 March 1992). Initially the company aimed to cater for the growing number of British and Dutch hauliers seeking a 3m load height within the 4m Continental height limit. A range of tyre equipment was offered.
The 18m wheelbase Volvo FL10 differs from the standard model by having a thicker section frame contoured at the back, and a modified rear axle suspension package using components from Volvo's bus air suspension_ Lower arch springs are fitted to the front end with smaller air bags on the rear suspension. All anti-roll bars have been retained.
Other features include a shallower 410-litre steel fuel tank from the FL6 rigid and smaller engine oil filters suit the reduced clearance to the front suspension. Volvo's RAE V90 drive axle, normally used in the more powerful F12 range, is also specified; its faster 3.1:1 ratio compensates for the smaller tyres.
Fitted with 60 aspect ratio tyres such as the HD75/HS45 range and the slimmest coupling, Volvo claims it can achieve a coupling height of 960min, allowing a 100m3 trailer under a 4m roof.
However, Swift has no real need for these mega-cube solutions with a 4.2m limit so it opted for a slightly shorter (1328m) trailer with dual pin positions at 1,100mm and 1,300nun. This gives full fleet compatibility with the standard tractor.
The truck's fifth wheel was just 1,030mm off the floor until Swift added a 50mm packing piece to give a height of 1,080mm. The coupling is a prototype dual-height device from VBG which allows the tractor to couple to any standard trailer. Air cylinders are used to raise, lower and lock into position anotherwise standard rubbing plate; two chassis mounted valves control the operation.
Volvo's high-cube FLIO is based on the FL10-310 4x2 tractor. This 18m-wheelbase, sleeper-cabbed model features the 10-litre TD102FM engine; a slightly downrated