More van and light goods vehicle operators may be unwittingly increasing their fuel and running costs, and reducing their safety, by overloading their vehicles.
The warning has been issued by TyreSafe, Britain’s leading tyre safety organisation, after the latest VOSA effectiveness report showed the LGV overloading prohibition rate by traffic enforcers increased from 66.9 per cent in 2008/09 to 72.7 per cent in 2009/10. Unless operators compensate for carrying heavy loads by increasing their tyre pressures to the recommended levels, their tyres will wear out quicker, their fuel consumption will increase, and their safety may be compromised.
"Overloading in itself is a serious safety hazard which operators must address, but even if they are carrying legal loads, they should ensure their tyres are adjusted and inflated to the correct pressure," says Stuart Jackson, chairman of TyreSafe. "If tyres do not contain enough air for the load being carried, they are much more likely to experience a rapid deflation which can result in a terrifying accident. There are also other significant downsides such as longer stopping distances, reduced stability, increased tyre wear and higher fuel consumption."
The effects of overloading and under-inflation are very similar. In these states, excessive heat builds up inside the tyre which significantly increases the likelihood of experiencing a dangerous blowout, particularly on high speed motorway journeys.
When under-inflated, the tyre's contact patch with the road surface is reduced to two smaller areas towards the outer edges of the tread. With the full vehicle load placed on these two areas, the tread wears at a much higher rate forcing replacement much earlier than would be otherwise needed. By running tyres at just 80 per cent of the recommended pressure, operators can expect tyre life to be reduced to around 75 per cent. If the pressure falls to 60 per cent, they can expect to achieve just 35 per cent of the potential mileage from the tyre.
When van tyres are inflated to the correct pressure for the load being carried, they help the vehicle to travel further on each tank of fuel and reduce the amount of CO2 emissions produced. Calculations from one TyreSafe member show when tyres are under-inflated by just 20 per cent (around 6psi ), three per cent more fuel is used.
"With the costs of running vans rising all of the time, operators can ill afford to needlessly increase their bills further," says Jackson. "By making sure that tyres are inflated to the correct level for the load being carried, any additional expense can be minimised as well as improving vehicle safety."
The correct pressures for both the laden and unladen state of the vehicle can be found in the vehicle manufacturer’s handbook, inside the fuel filler cap or on a plate located on the front door sills.