Daf launches 6x2
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MOST OPERATORS will use two-axle tractive units for 38tonne operation, Daf sales engineering manager John Beveridge said last week at the launch of the company's 6x2 tractive unit.
He said the two-axle tractive unit option offers a lower purchase price, lower maintenance costs and greater traction. "It also offers compatibility with current tractive unit fleets, trailers are available and easy to convert to three axles, and spare parts can be rationalised."
But he recognised that for certain operators, specifically those with tipping or refrigerated semi-trailers, three axle tractive units would be preferable.
Another advantage of the "three and two" configuration identified by Mr Beveridge was that it suited short wheelbase trailers and attracted lower vehicle excise duty currently.
However, he cautioned that construction of today's tandem axle semi-trailers is a "major limiting factor to payload with this configuration."
Mr Beveridge said that his research had shown that over 80 per cent of in-service tandem axle trailers in Britain are designed for only 9.5 tonnes through the kingpin and 20 per cent are designed for 11.5 tonnes kingpin load.
He also wanted to remind operators that close coupled tandem axle bogies are limited to 18 tonnes and a wide-spread bogie is needed for 20 tonnes. So the maximum payload for a three-plus-two 38-tonner can only be achieved with an 11.5tonne kingpin and a wide-spread bogie, and even then the load will need to be concentrated at the front of the semi-trailer.
Daf reckons that the optimum relevant axle spacings (tractive unit rear axle to semi-trailer rear axle) is 8.4 metres (2Crft 6in) for two-plus three configurations and 6.6 metres (21ft 8in) for three-plus-two combinations. Daf's new FTG3300 DKX has a wheelbase (measured from front axle to drive axle) of 3.8 metres (12ft Sin) and the second steer to drive axle dimension is 1.3 metres (4ft 6in).
The six wheeler's engine and transmission are unchanged from those fitted to 3300 4x2 units, being the DEX 11.6-litre turbocharged and charge cooled system with a maximum power rating of 246 kW (330hp) driving through a ZF 165-130 16-speed synchromesh gearbox.