Most people in the trucking industry know that incorrect tyre pressure leads to increased tyre wear and that tyre pressure and wear are intrinsically linked. What is a surprise to many, is the degree that as little as five-psi difference can make, especially on dual wheel sets.
Uneven or incorrect pressures are the most common preventable cause of excessive tyre wear. Insufficient pressure causes increased and uneven wear, higher fuel consumption and poor handling.
Many operators run their fleets at higher than recommended pressures to avoid issues from low pressures. However, too high a pressure will cause uneven wear and has been associated with increased incidence of punctures and cuts.
How can we determine what pressure to run set the tyre to? Well, it is only by referring to the recommendations of the tyre manufacturer for the type, application, size, and expected load. Simply setting the pressure to a universal 95 or 100 psi will not provide the best ride, wear, and life expectancy. Quite often the required pressure may be closer to 85 psi.
A study by the U.S. FMCSA found that 41 per cent of tyres surveyed were at least five psi under-inflated and 31per cent of tyres were overinflated by five psi or more. Additionally, 72 per cent of dual tyres were found to have mismatched pressures of five psi or greater, which is a cause of serious tyre wear issues.
You may wonder how much difference five-psi can make. Well, in dual wheel sets it can make a huge difference. A five-psi difference between commercial vehicle dual tyres can create a 6mm difference in tyre circumference.
In general, a typical commercial trailer tyre makes about 310 revolutions per kilometre. This difference in diameter can cause the wheel with the lower pressure and smaller rolling diameter to skip to keep it moving at the same speed as the adjoining tyre.
Over 100,000 kilometres, the smaller tyre will drag that 6mm difference about 31 million times, which equates to 186 kilometres. The smaller tyre skipping across the roadway for those 186 kilometres will result in scrubbed tyres and create patchy wear patterns.
At the same time, the larger tyre will suffer from internal damage due to the dragging force of the smaller tyre, which can also result in premature failure.
Therefore, on dual tyres, only a five-psi variance between tyre pairs can make a huge difference. The answer to accelerated tyre wear is for truck owners and fleet operators to set up a frequent schedule of tyre inspection and pressure maintenance and/or install a tyre pressure inflation system, such as Hendrickson TIREMAAX PRO.
Tyre pressure inflation systems have the added advantage in that there are no safety issues that occur when tyre inflation it is carried out by a technician. These systems can pay for themselves within a year or two, depending on application. The savings come from reduced tyre expenses, fuel savings from not driving with under-inflated tyres and reduced labour time needed to regularly check pressures.
The most important point is to regularly check your tyres for damage, wear, and pressure. Tyre pressures should always be maintained at the recommended levels to reduce costs and downtime.