Stevenson Concrete operates 52 concrete agitator trucks out of their Auckland sites. Business is booming and four more have been ordered. Operations manager Pamela Veldman says they had 42 trucks when she joined the company nine years ago; there will be 54 in the fleet when the new trucks are commissioned and a couple of oldies are retired.

For years Stevenson‘s concrete truck fleet has been predominately Japanese, but that changed last year when three MAN TGM 8-wheelers, and five MAN TGM 6-wheelers were ordered. The truck‘s weight distribution suited the role better than the others and Pam says Penske did a great job ensuring the trucks were well spec‘d to meet the unique role.

She points out that the trucks, “work in a harsh environment”. They are constantly wet and when the sun is out, there is usually cement and dust blowing around and sticking to any wet spots. Building and other delivery sites rarely have good access and trucks have to handle rough and inconsistent surfaces getting in and out. On top of that they‘re handling a time crucial product, which proves expensive to put right if it goes off before delivery. And they have to negotiate Auckland‘s notorious traffic.

A magnetic device and trip wire are used to safeguard the automatic bowl washer when it‘s in use. The arrowed switch on the dash controls engine revs when the truck is stationary. The dash is clean and easy to use.

AMT gearboxes are not acceptable to Stevenson‘s concrete truck drivers, their inability to move smoothly at very low speeds precludes them from doing work like kerbing where they have to move while discharging concrete into a moving machine. AMTs can also have difficulties moving smoothly in tight areas (see the Isuzu Giga story in this issue for more details about AMT
issues). The MANs are equipped with ZF 9-speed manual transmissions, which are proving an excellent choice.

New Zealand Trucking had the opportunity to go out on a delivery in one of the new MANs, it was driven by Luis Vanegas and beautifully cleaned when we arrived at Stevenson Concrete‘s Penrose plant. Keeping his truck clean is important for Luis, he says it‘s his office when he‘s working and he likes to treat it that way.

Stevenson‘s bold green and yellow livery suits the MAN  styling, and the wide front tyres, high cab and black front panel combine to make a serious visual statement that this is a truck that will do the job. MAN call their cab a ‘C‘ (for compact) cab. Inside it‘s roomy and comfortable with excellent vision; it doesn‘t come across as compact in any way. The driver is treated to a comfortable  Isringhausen air seat and the controls are well laid out.

Luis Vanegas

Born in Columbia, Luis Vanegas came to New Zealand 17 years ago looking for a good place to live with his wife and bring up his two boys. He says there were good opportunities and he liked what he found; a year later he became a New Zealand citizen. 

Luis was a truck driver before leaving Columbia; he‘s now 52 and says, “All my life was working on heavy transport”.

He reckons his decision to make a new life here was a good one. His wife is a kindergarten teacher, his oldest boy is working and his younger son is studying at Unitec in Auckland.

It‘s a busy yard, and we‘re third in line for a load, but it‘s efficient and the line moves quickly. Luis reverses the truck under the batching plant for a load of concrete, this is a ‘wet batch‘ plant and concrete is premixed when it‘s loaded into the bowl. His ability to reverse is amazing; drivers are usually a little slower to release the clutch when in reverse. But Luis knows how to go backward just as well as he knows how to go forward. Obviously he spends a lot of time in reverse, and in tight situations; the two reversing cameras that provide a  display on a dash-mounted screen ensure all round visibility is not a problem. Stevenson‘s drivers didn‘t like the concave glass in the MAN mirrors and the company has replaced it with flat glass. The mirrors are heated; they often get splashed with water and the sooner it dries off the less opportunity there is for dust to stick to the mirrors and affect visibility.

The truck has a GVM of 26,000kg and a tare of 9950kg.

It can usually carry five cubic metres, but some aggregates are particularly heavy and we only get about 4.5 cubic metres on board for this delivery. Out on the road the truck runs well, and with a modest 290hp the truck performs surprisingly strongly, however the Auckland traffic is living up to expectations and it‘s a stopstart trip crossing the motorway to reach the destination a few kilometres away. The truck handles the road conditions well, it keeps up with the traffic flow and the all-round disc brakes smoothly bring it to a halt. There are no opportunities to use cruise control and the exhaust brake doesn‘t get much of a workout because of the slow inconsistent speeds.

The automatic bowl washeris an impressive machine that cleans the inside of the bowls out in about five minutes.

MAN‘s 6-cylinder 6.871-litre engine appears to be a neat piece of German engineering; it meets Euro 5 without SCR, and no DEF is required. Its subdued note sounds sweet and the engine is free revving; the green economy band runs from 1100rpm through to 2300rpm and the red section doesn‘t kick in until 2800rpm. Going through the gears, Luis takes the engine over 2000rpm before changing up. He uses all the gears when it‘s loaded, but will skip shift coming home empty. The ZF box is a synchro unit and in our opinion is the most driver-friendly 9-speed manual currently available. The diff ratio is a high 4.63:1, which gives the truck plenty of assistance when taking off on a steep surface, and allows controlled slow work.

When we arrive, four Stevenson Concrete trucks are already on site, waiting for their turn to feed the hungry truckmounted  concrete pump that‘s pumping to the crew placing the concrete. Luis prepares the truck as much as possible and moves in when it‘s his turn, seamlessly continuing the concrete flow.

Traction control

A large new commercial building is being built on one of the delivery sites we visit; it‘s flat, the clay surface is dry and the day is fine, so traction isn‘t a consideration. But with a bit of rain it could easily be a very different situation.
The Stevenson MANs are equipped with cross-locks and diff-locks, and they‘re used regularly. Wide 385/65R22.5 front  yres and 295/80R22.5 tyres fitted to steel wheels spread the load over a lot of ground, so the chances of a truck  getting bogged down are minimised. The agitator bowls are placed well back, so even when empty there is substantial weight on the driving wheels and a 4.63:1 diff ratio means power can be delivered to the wheels gently.

The TWS concrete bowl is powered through a PTO-operated hydraulic pump. Luis positions himself on the back of the truck where he can see the concrete flowing into the pump and controls the flow with a remote control. The engine revs are often surprisingly high – 1700rpm when the bowl is taking on a mix or being cleaned. A switch on the dash allows the driver to set the revs. When discharging, the revs are usually lower and controlled via the remote.

The load is soon discharged and we head back to Stvenson‘s Penrose site. The truck isn‘t required immediately and Luis backs it into the automatic bowl washer to clean out the bowl. He must remain out of the cab while the bowl is cleaned, so after setting the engine speed he climbs out and clips a lead to the door handle and attaches a magnetic device to the door.

Only then can the washer be activated and it automatically stops if the truck is moved or the door opened. The system is designed to prevent damage to the cleaning system that automatically slides into the bowl and cleans it spotlessly in five minutes.
As soon as Luis finishes cleaning the bowl, another job comes through and he reverses under the batching plant and picks up another load of concrete, washes the back end of the truck down and heads into central Auckland to drop it at a more challenging site between existing businesses.

Luis and the MAN handle the difficult role comfortably. It‘s not hard when you‘ve got the right men for the job.