Saturday, 1 February 2014

The overloading perils of 7.5 tonners.

One of the most frequently overloaded trucks is the 7.5t 2-axle rigid. The low axle weight limits on these vehicles make them notoriously easy to overload, especially the front axle.

Although it's largely felt in the industry that this weight of vehicle is in decline, replaced with either 3.5t,  4.5t or larger 2-axle rigids depending upon the application, the number of 7.5 tonners registered actually increased in 2013. The overall numbers are still way down on on their hey day when they accounted for almost a third of the light truck market but they are still on the road in significant numbers.

Clearly someone has a need for them but the problems of getting the axle weights right still remain. Pull back the curtain on a 7.5 tonner and, assuming it's legally laden, there will be an awfully lot of fresh air. And it is surprising how many people still think that all of that 'space' is usable. The truth is that the amount you can legally get on a 7.5 tonner is actually quite small.
This 7.5 tonner is actually fully loaded!

One of The perthe most common problems is front axle overloading when these vehicles are being used on multi-drop work. The natural tendency is to put loads right behind the headboard which is fine if weight is then placed behind the back axle. But as soon as that weight on the rear is removed there is a real danger that the front axle will become overloaded.

It can be a tricky concept to grasp. How can removing some load cause the vehicle to be overload? Surely the weight has decreased? Yes the overall weight has decreased but the weight on the front axle has increased.

It's basically a see-saw effect with the rear axle as the pivot point. If you put weight behind the back axle, it will reduce the weight on the front axle. Take that weight away and the front axle weight increases, put it back on and the front axle weight will decrease again. We refer to it as a diminishing load problem; despiute the fact the overall weight is dropping, the front axle weight is increasing.

It's exactly what happens when one person gets of a see-saw - the other person is lowered to the ground. If that person gets back on the see-saw again then, assuming they weigh the same or more, the person who stayed on will be raised again.

Our OnBoard Load Indicator we developed with the 7.5t market in mind. A display that shows front, rear and gross weight all the time with no operator input, it was specifically designed for vehicle on multi-drop work where the axle weights can change throughout the day.

The Axtec OnBoard is keenly priced and can be fitted in half a day. The costs of having a vehicle prohibited at a weight check could be enormous and far in excess of protecting the vehicle from the very common common diminishing load problem.

If overloading your 7.5 tonners is easy, the solution could be quite simple too.

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