Misaligned wheels on trucks and trailers can lead to an increase in fuel and tyre costs, yet it’s often a hidden problem. But regular checks can highlight any problems and help trucks to run more efficiently and save operators money.
This article was originally published in the September 2021 issue of Commercial Vehicle Engineer magazine. To read the full issue, click here.
Potholes are a growing problem in England and Wales: about 1.7 million of them were filled in by councils in 2020/21, an increase of 200,000 on the previous 12 months, according to statistics from the Asphalt Industry Alliance.
While local authorities spent almost £94 million filling in potholes, what is harder to define is how much it costs transport operators, who must deal with the damage to their vehicles that going over them can cause.
Common damage arising from potholes affects the alignment of the vehicle’s wheels. While commercial vehicle wheels are supposed to point forwards, hitting potholes can affect this and leave them at an angle. While the degree of misalignment potholes can cause sounds small – perhaps one degree or less – the effects can be significant.
“Depending on how extreme a particular case is, wheel misalignment can cause real trouble for a vehicle’s tyres,” says Richard Tawlks, UK equity business manager at TruckForce, Goodyear’s international truck tyre service network. “If the wheels have been considerably misaligned, you’ll ultimately see quite extreme tyre wear.
“If wheels are badly misaligned, what essentially happens is that their tyres are pushed down the road at angle. This results in what’s known as feathering, whereby the edges wear down quicker than the rest of the tyre.
“If it’s only a minor misalignment, the tyre’s life could be shortened by 10 to 20%. If the wheels are badly misaligned though, the edges of the tyre could very well wear down up to 60% quicker than they should. So, from a cost point of view, the danger of wheel misalignment is ultimately that you wear through and therefore need to replace your tyres a great deal sooner than you should.”
Given that truck tyres cost hundreds of pounds each, this can be a significant burden on operators. Another cost that results from wheel misalignment is increased fuel consumption, adds Malc England from Haweka.
“A one-degree misalignment on one axle could increase fuel consumption by about 5%,” he says. “It also means that there is increased production of carbon dioxide and other harmful emissions and increased stress on mechanical components.”
England adds that there are various causes of wheel misalignment, apart from potholes, including that a steering joint may have been replaced and there are no guarantees that the replacement restores the vehicle geometry to within the vehicle manufacturer’s tolerance. “In addition, the vehicle may have made contact with a kerb, or might regularly run off-road or over uneven ground.”
But wheel misalignment is something that is easy to miss – it doesn’t necessarily make an appreciable difference to how the vehicle feels to drive.
“It is not always that the problem is being ignored by a driver, but it is about who is analysing the vehicle data to identify if the running costs are outside of the expected parameters,” adds England. “If the vehicle is part of a large fleet, a driver will have many key performance metrics to focus on and tyre life and fuel efficiency may not be at the top of their agenda. It will be the fleet manager that may be the first to observe that a particular vehicle is using more fuel than expected or the average tyre life is significantly different to other vehicles in the fleet. But all of these symptoms are lag measures, which come to light when there is a problem.”
Regular alignment
With such costs that can be incurred, it is important for transport operators to check their vehicles’ wheel alignment regularly, says England.
There are many wheel alignment solutions on the market, and some now use laser technology to measure the vehicle geometry, such as those from Tecalemit Garage Equipment Ltd, sold by Haweka. “More sophisticated models accommodate the wireless transfer of data to a PC to enable the workshop technician to produce reports of the vehicle configuration,” adds England.
For instance, Tecalemit’s AXIS 500s model measures total toe, single toe and rear axle out of square. “With an inclinometer for measuring turning angles at +/-20o without floor scale, the AXIS 500 provides the technician with the capability to configure the vehicle to within manufacturer’s tolerances,” notes England.
Meanwhile fellow wheel alignment specialist Pro-Align works to manufacturer details on wheel alignment.
“If the manufacturer wants it done a certain way, we do it a certain way,” explains David Mendoza, Pro-Align’s national sales manager. “For instance, if a truck has independent front suspension, there is a different way of doing it if it doesn’t have independent front suspension. We have to stick to what the manufacturer says to ensure the truck comes out of the repair shop like it has just come out of the factory.”
Timing
As mentioned, wheel misalignment can be a hidden problem as it doesn’t always affect a vehicle’s handling. Therefore, it is recommended to regularly check the wheel alignment of trucks, although as Mendoza explains, how regularly depends on what the truck does.
“If the truck is doing intercontinental driving the timescale between wheel alignment checks will come down to weeks rather than months,” he says. “If you’re driving a bus [in urban areas] and bouncing off the curbs quite a lot then you will be checking the alignment a lot more than if you are driving up and down a motorway. But on average, about once a quarter is sufficient for a check.”
Clive Seabrook, CEO of Pro-Align, adds that tests take just a few minutes to complete but they give the operator a clear report showing where there is/isn’t misalignment. “This gives clear direction to where the truck needs to be adjusted to ensure it is aligned and there is a clear record of that process having taken place,” he says. “In terms of health and safety and any matter of operational efficiency, that record is there in relation to any tractor or trailer unit.”
In-house investment
In terms of what equipment should be used to check wheel alignment, operators generally have the choice to invest in their own equipment or book in a mobile service.
Seabrook says that operators should invest in their own system, along with training and orientation for key staff in an organisation to be able to carry out the alignment.
“There are a couple of reasons for this: it is about building the awareness within organisations about how important this is from a cost perspective and from health and safety perspective,” he explains. “If you are driving a truck that is badly misaligned there is evidence to show it increases driver fatigue. On that basis we believe there are good commercial reasons to be testing the alignment on a regular basis and, if your fleet is big enough, in house is the most efficient way to do this.
“Other systems may miss is the relationship between the tractor and trailer. If you have your own in-house system in the workshop, it is relatively easy to carry out the alignment on both the tractor and trailer. In some cases, mobile units can just do the tractor unit, which sorts out that out, but the trailer could still be misaligned and you’ be scrubbing the wheels on the trailer.
“We would advocate that an in-house system, in the long run, is financially the more viable solution.”
Mendoza adds that a lot of operators do check sheets, so if the driver says the truck is pulling all the time, if they have an in-house system can take the doubt away quickly. “Some haulage firms will take a truck off the road until the problem is rectified due to health and safety so if they have an in-house system, it can be done straightaway, rather than waiting for, say, a week for someone to come in and do it.”
However, once a misalignment problem has been identified, it is often an easy job to rectify. “If you have a capable workshop guy, he can adjust a tyre or the suspension,” Mendoza says. “With most trucks it is the steering axle that does it and that takes about 20-25 minutes to get it fixed, unless it’s an old dog that’s seized up, then it takes longer.”
This article was originally published in the September 2021 issue of Commercial Vehicle Engineer magazine. To read the full issue, click here.
