Big movers

Compared To Some Types Of construction equipment, haulers are not big sellers in terms of unit volume. But they are big sellers in terms of capital investment and are vital for most quarrying and earthmoving operations, which combine to make them a key market for construction equipment manufacturers.

According to Off-Highway Research, over 2600 haulers - split between articulated dump trucks (ADTs), rigid dump trucks (RDTs) and scrapers - were sold into Western Europe last year.

ADTs are the most common type of hauler in Europe with almost 2000 sold last year - up +6% on 2004 - and Off-Highway Research predicts that sales will grow steadily up until 2009. “There has been a steady growth in demand for ADTs in Europe but specific projects to create peaks in demand,” said Volvo Construction Equipment product manager Jonas Thoursie. “At the moment the biggest demand seems to be for the larger machines, above 30 tonnes, which offer greater hauling efficiency.”

RDTs accounted for over 600 of the total number of haulers sold last year, a gain of +28% on sales in 2004. But Off-Highway Research is expecting sales to decline slightly each year through to 2009.

According to the company, sales of scrapers, which are a rare sight in Europe and more popular in North America, dropped to six units in 2005 but are expected to grow to 11 or 12 per year through to 2009. Caterpillar product specialist Sergio Tigera also believes that scraper sales are set to grow in Europe. “Scrapers are a more practical option for many applications and are much easier to operate than ever before,” he said.

“We are already seeing a stronger than normal demand in France the UK, South Africa, the Middle East and other African countries. A railway project in Saudi Arabia has ordered 250 631G scraper units to carry out a 300 km section of the work because it has been determined that it represents the lowest hauling costs. There is strong potential for growth in scraper use on a range of infrastructure projects in both Eastern and Western Europe.”

New Engines

The first engines to be affected by the European Stage IIIA engine emissions regulations are those within the 130 and 560 kW powerband - a bracket which covers the majority of ADTs currently in production. Introduction of the new regulations has resulted in a wave of new machine launches for other types of construction equipment. But a similar pattern has not emerged in the hauler sector, although some manufacturers may be saving their new models for unveiling at Intermat in Paris, France later this month.

According to Mr Thoursie, the transition between Stage II and Stage IIIA powered machines is smoother for haulers than for other lines of construction equipment. He believes that this is why there hasn't been a widespread launch of new models in the hauler sector. “The specification of Volvo's V-ACT Stage IIIA compliant engine haulers which is fitted in all five of our models is very similar to the Stage II machines,” he said.

“The new engines have the same displacement as the old ones and the fuel economy is very similar. In other product lines the move from Stage II to IIIA has been used as an opportunity to re-engineer the design. Some of the re-engineering on other equipment may have been necessary because the Stage II engines used were significantly different to the Stage IIIA units. The similarity between the engines used in our haulers, meant that a major upgrade was not needed.”

Cat's 23 tonne 725 and 28 tonne 730 are powered by the 225 and 237 kW versions of Cat's own C11 ACERT engine. The other models in Cat's ADT range are the 32,7 tonne 735 and 38 tonne 740 which have C15 ACERT engines which produce 287 and 325 kW, respectively.

Terex unveiled the new Stage IIIA powered versions of its larger ADTs at the Association of Equipment Distributors meeting at San Diego, US in January. The company's TA35 and TA40 have been updated with the addition of new Detroit Diesel Series 60 Stage IIIA compliant engines - 298 kW unit for the TA35 and 335 kW for the TA40.

The TA35 has a maximum payload of 32 tonnes and has a heaped capacity of 21 m³, while TA40 can carry up to 36 tonnes or 23 m³. Other improvements to the TA35 and TA40 include automatic limited slip differentials in each axle to add traction and a new front end suspension system to provide a better ride. On the serviceability front, the engine oil change is now every 500 hours and the design features a ground level tilting cab to provide easier access. In the cab, the controls have been ergonomically redesigned with new instrument clusters.

According to Terex product manager Fred Casten, the new TA35 and TA40 ADTs deliver the same performance as the existing TA27 and TA30 models. “We have taken the latest technologies and applied them to our new heavyweight models. The upgraded features on the TA35 and TA40 give customers the power to load more, carry more and dump more.”

Bell has also updated its D-series hauler range with new Stage IIIA compliant engines from Mercedes Benz and the first of the machines with the new power unit will roll off the production line this month. According to Bell head of design Peter Bell, the Mercedes engine needed very few changes in order to comply with Stage IIIA.

“The Stage II compliant Mercedes engine came very close to complying with the Stage IIIA regulations,” he said. “Internally some of the piston geometry had to be changed and the turbo on the series five engine needed to be reconfigured. Because the difference is so minor we have been able to incorporate the new engines without the need for a complete redesign.

“Nonetheless, the compact design of the new Mercedes engine has also enabled the front end of Bell's ADTs to be redesigned with a shorter nose.“The combination of a lighter engine and shorter nose on the power unit means that we have been able to reduce the deadweight of the machine,” he said.

“The focus of our hauler range is on fuel efficiency,” he added. “Converting fuel to work, or in the case of haulers, moving material, is a function of the machine's power and drive train efficiency, weight and rolling resistance. Getting all of these to combine to the best advantage has enabled us to achieve substantial fuel savings.” According to Mr Bell, the fuel burn to tonnes moved for Bell's trucks is up to -25% less than that of other manufacturers.

Moxy's latest ADT will be on display for the first time at Intermat. The upgraded MT36 is now powered by a Stage IIIA compliant 294 kW Scania engine which is a lower rated version of the 335 kW unit which is used in the MT41. The new MT36 can carry a maximum payload of 32,7 tonnes and has a heaped capacity of up to 21,5 m³.

The new model features independent front suspension, which allows for free movement on one side without movement on the opposite side to give maximum ground contact. Like the MT41, the MT36 will now be fitted with hydraulic multiple wet brakes as standard as well as electronically controlled automatic lubrication.

JCB is also expected to launch new machines at Intermat. Case has said that its hauler range, like the rest of its construction equipment lines, will be progressively upgraded to be powered by Stage IIIA complaint engines.

Komatsu and Hitachi are remaining tight lipped about their ADT plans. However, Hitachi has told CE that it is currently working on an upgrading its 75,4 tonne EH750-2 RDT with a new engine and new cabin layout and it is expected to be launched later this year.

Maximum Traction

Volvo's range of D-Series ADTs may not have been re-launched following addition of the Stage IIIA complaint V-ACT engine but are now also available with an Automatic Traction Control (ATC) system. According to Volvo the ATC system will reduce wear and improve fuel consumption. The system monitors wheel slippage and engages the 100% dog clutch locks when needed. This allows the hauler to get maximum drive when required but maximum drive is not used all the time.

According to Volvo, some less experienced operators leave their haulers in all wheel drive permanently even though conditions on site don't demand it. Over use of all wheel drive can result in increased fuel consumption, tyre wear and mechanical wear.

Tyre Trouble

The current worldwide shortage of tyres is expected to continue impacting on deliveries of all types of haulers throughout this year and beyond. “Sourcing tyres is still a challenge for the hauler market but the extent of the problem does seem to vary from region to region,” said Mr Thoursie.

The shortage has in part been a result of the international construction boom and consequent high demand for equipment and raw materials, particularly in China, India, the US and the Middle East. A massive fire at tyre manufacturer Bridgestone's 40000 m² factory in Japan in September 2003 has also had a huge impact on the tyre supply chain.

According to Bridgestone, the worldwide demand for off-highway tyres began to exceed supply at the end of 2003, and by the end of 2004 manufacturers could not keep up. This has forced equipment manufacturers to take some rather unusual steps to ensure they deliver their machines.

Last year, for example, Volvo and Caterpillar said they were delivering some vehicles without tyres, with the promise to deliver them later or letting customers buy their own. Goodyear is also recommending that users consider fitting bias- ply tyres on rear axle positions if radial tyres are unavailable.

However, in a bid to ease the shortage of off- highway tyres, Bridgestone has announced plans to expand its production facilities in Japan by about +20 % by the beginning of 2008.

Bridgestone Michelin and Continental have also said that they are making plans to increase output but the benefits are unlikely to be seen in the supply chain until 2007 at the earliest.

Goodyear off-highway global customer account manager Tim Good said, “The high demand means that basic tyre care is becoming more critical. Only around 7% off-highway tyres are removed because they are worn out while tread and sidewall cuts and impacts account for 74% of replacements. Weekly checks on tyre inflation, regular tyre rotation, reduced payloads and driving slower can greatly improve tyre service life.