THE DEFINITIVE TRUCKING SITE

September 2007

The GCM envelope for this 56t combination under test remains constant at 56t. The question remains: How many more payload units can be squeezed into the envelope without shortening trailer life? Modern computerised finite analysis allows us to stretch the boundary.

If you're looking for increased productivity and profit, just look behind. Hitching a tired old trailer to a new prime mover is a contradictory business decision. It robs the new hauler of all the modern design features that are meant to save fuel and increase productivity. If the task is a low-distance operation combined with long standing periods such as border crossings, then a worn-out, old truck married to a tired, old trailer makes sense - in this scenario it's just not possible to recover the returns required when investing in new equipment. But if the job is a long-distance, line-haul job with high annual kilometres then a new lightweight trailer is a must. The payback from new trailer technologies is just too big to ignore and it mounts up quickly in terms of ton/kilometres - the figures prove it writes FleetWatch technical correspondent Dave Scott.

Travelling the roads, often tailing an old trailer that crabs down the road in its task to increase fuel consumption, I wonder if anyone has done the sums of staying locked into old, heavy technology. The answer seems to lie in the fact that these old trailers are paid-up pieces of equipment. And everywhere I go, trailer maintenance ranks as low priority - another cost reducing, minimal cash flow factor. No one is watching productivity - how many more ton/kilometres the new trailers can produce for the same fuel consumption.

All focus on the prime mover
The truck OEM's do so much marketing on their prime movers that market perceptions lock into horsepower instead of torque and sometimes driver training to improve productivity. Horsepower, torque and driver training don't matter a dot if trailer frontal areas are excessive. Combine speed over 30kph with a large frontal area and high fuel consumption is guaranteed. 

Old trailers were built with one thing in mind - the overload. The tare masses were excessive to protect trailer integrity. Again, no amount of driver training can increase payload productivity on an overweight trailer - it's a permanent penalty. All of this was addressed in a the FleetWatch August 2007 edition in an article titled A highly-developed 56-40-40 formula where Barloworld Logistics were shown to be running 56t GCM at 40l /100km with 40t payload. However, the article did not compare old to new technology. 
 

Analyse the impact of changes in trailer design
The problem with payload is that most see this as a frozen factor. When payload is combined with road dynamics - trip times, distance, fuel consumption and cost - that is finally combined with annual productive days available, then the payback for using modern trailer technologies is very evident.

So an old heavyweight interlink weighs in at 11 384kg with a payload of around 35,4t while a new lightweight Afrit interlink has a tare mass of only 7 200kg and payload of 39,5t - a gain of 4,1t. What's the impact of this in terms of productivity factors, cost per kilometre and cost per ton? FleetWatch decided to forecast this with conservative accuracy using Fritz Hellberg's HTM TranSolve software.

With Hellberg's assistance, the gains made by employing new trailer technologies are detailed on the spreadsheet accompanying this article. The assumptions are all based on using a standard route - a return trip between Johannesburg and Durban. What is most revealing is the heavy cost penalty for being laden only one way regardless of whether the heavy or light/light interlink trailer combination is used. Getting return loads is vital to survival in road transport. Naturally, the heavy interlink suffers a fuel consumption penalty of nearly 2 litres/100km on the empty leg for the extra 4t in tare mass.

The cost per kilometre rises with an investment in new trailers but this is more than offset by the payback in productivity - the lightweight interlinks just earn more money per trip. Trailers do not last forever and 'horses-for-courses' still applies as the new lightweight designs will not do well in off-road applications. But the fact remains that there are many new truck tractors out there struggling with very old trailers that are a drag on costs.

Hellberg proves again that it's not about price. It really is a matter of how road transport equipment is used. The only way to measure this is by comparing payload units moved though both distance and time, and set off against energy used on specific routes. Forecasting accuracy is a key to survival.

But apart from the scrapheap, there is a place for old trailers - slow, cross-border operations and a temporary warehouse are two applications that come readily to mind. There are also so many freight carrier trucks out there with unused gross combination masses. However, if you want to increase productivity and profitability just look behind your road transport fleet.
 

A trailer is not a static warehouse - thanks to proven software and experience we are now able to forecast trailer productivity with acceptable accuracy  Fritz Hellberg