Two-thirds of Europe's truck combinations are driving around with incorrect wheel alignment, and many also have the wrong tyre types and tyre pressures.
Those are among key findings of a large-scale test carried out by tyre manufacturer Michelin in partnership with Volvo – and the pair now reckon that the resulting fuel and CO2 emissions penalties could be as high as 14.5%.
Arne-Helge Andreassen, business area manager for tyres and wheel alignment at Volvo Trucks' aftermarket department, explains that Volvo and Michelin recently completed a two-week trial, under the auspices of from SP (Technical Research Institute of Sweden), to check the figures.
They compared two identical combinations, each using a Volvo FH 4x2 tractor, equipped with a 500hp 13-litre Euro-5 engine hauling a fully loaded box-bodied trailer and grossing 40 tonnes. One was equipped with optimal tyres at the right pressures and with correct wheel alignment, while the other was driven with a variety of incorrect – but realistic – wheel alignment settings and tyre parameters.
Jacques de Giancomoni, technical account manager at Michelin, explains that the trucks were equipped with instruments that monitored precise speed, tyre wear, tyre pressure, rolling resistance etc. Also, prior to each test cycle, the two combinations were driven for one hour on the track to warm up the engines, transmissions and rear axles, and make the test data as reliable as possible. Additionally, test engineers compensated for factors such as wind, rain and temperature.
Hence the 14.5% fuel penalty claim – and de Giancomoni says that choice of tyres alone can result in an 11% differential, with tyre inflation accounting for 1% (within safety limits) and wheel alignment 2.5%.
"One-third of fuel consumption stems from the tyres' rolling resistance. Having the right tyres is of paramount importance. In addition, checking tyre pressure - which has a significant effect on fuel consumption - is also important," comments de Giancomoni.
"There is a lack of awareness in the transport industry about the importance of checking tyres and wheel alignment, on both truck and the trailer," adds Andreassen. "At our dealers, we can help haulage companies check the entire combination and correct any problems. If everyone did this, it would have a significant impact on CO2 emissions."