NUMBER ONE
FOR COACH, BUS & MINIBUS

Back to top of page
ADL 2019
PRINT
THIS PAGE
Back to previous page
December 19 2018
By Michaela Peacock

Michaela writes for routeone and Group Tourism & Travel magazines


Wheel loss is no mystery: Ensure your
vehicles are up to standard

Wheel loss is a preventable accident, ensure you don’t make the mistake of sending a vehicle out that is not up to standard

Wheel loss is a serious concern for operators, but it is an incident that is preventable.

In some cases, wheel detachment has resulted in major injuries and even fatalities.

Checkpoint’s indicators can help prevent wheel loss

There is no way to guarantee a wheel won’t become detached, however, with good maintenance together with an understanding of the issues surrounding wheel loss, the accident can be significantly reduced and prevented.

“Many people refer to loss of wheels as a mystery. Research shows that there is no mystery,” says DVSA.

“Someone is responsible for wheels becoming detached from commercial vehicles. Following the guidelines may help to ensure that it is not you.”

Responsibility

If a wheel-loss incident occurs, there is no one person at fault, but in fact multiple.

The vehicle’s roadworthiness is determined on many factors, as revealed in the FTA/IRTE’s Best Practice Guide to Wheel Security, it sates how each person has a role to play in wheel-loss prevention:

Drivers

Drivers have a legal responsibility to ensure that the vehicle they use is free from visible defects. They are legally required to report any defects they have identified.

As part of their pre-use checks, drivers should always carry out a visual inspection of the vehicle wheels for security.

Operators/maintenance staff

It is a requirement for operators to maintain their vehicles in a safe and roadworthy condition always.

Wheel security defects are considered serious by DVSA and Traffic Commissioners, as they are deemed to be attributed to a poor maintenance regime.

Operators should ensure that maintenance policies should be sufficiently robust to prevent wheel-loss defects from occurring.

Third party maintenance and service providers

Operators who use outside contractors for vehicle maintenance (including tyre companies) should check to ensure these companies have sufficiently robust wheel inspection and fitment policies in place.

The guide adds: “It should be noted that regardless of any third-party maintenance contract, including outside tyre contractors, the operator is ultimately responsible for maintaining vehicle roadworthiness.”

Loose fixings

There are many reasons why wheel fixings become loose. Wheels feel the strain day in, day out – they need care and attention.

The guide explains: “If one wheel nut loosens then these forces are distributed over the remaining nuts.

“Most the forces are spread to the adjacent nuts causing them to loosen as well. As more nuts become loose the process accelerates as the overall clamping force decreases (clamping force being the loading that is created by the studs and wheel nuts compressing/pinching the wheel(s), hub and drum together).

“When the clamping force is less than the forces on the wheel, it will move relative to the hub. This results in side loading and a loosening of the remaining nuts which, if not spotted in time, leads to elongated stud holes, fatigue failure of studs, fretting fatigue cracks and wheel separation.”

Prevention

Checkpoint Safety – wheel safety specialists and creators behind the world’s first loose wheel nut indicator – lists seven main causes for wheel loss:

  • Excess vibrations
  • Worn/damaged studs
  • Stud hole elongation
  • Incorrect torqueing
  • Inaccurately calibrated torque wrench
  • Incorrect use of air impact tools
  • Inconsistent safety inspections.

To help prevent wheel loss, there are five steps from Checkpoint.

Check: Wire brush the base and threads of each stud to remove any rust or dirt that could compromise the nuts. Ensure the studs and nuts are free of dirt and grease and check for any damage to studs and threads. Replace any parts that are worn or damaged, and ensure correct replacement studs are used.

Fit: Attach the wheel and torque the nuts to the manufacturers’ specification using a correct sequence.

Apply: Fit a wheel nut indicator of your choice. Checkpoint recommends fitting one in red as a reminder to re-torque that wheel. Fit the indicators in a recognisable pattern, it recommends point to point.

Re-torque: Inspected and re-torque the wheel after either 30 minutes or 40-80 miles. If movement has occurred, a second re-torque is necessary. If on the third inspection any further movement is visible, the wheel should be removed and a full investigation carried out. If there is no movement, replace red products with yellow.

Inspect: Carry out daily checks as part of your standard maintenance procedure. Ensure periodic re-torques are completed in line with maintenance procedures. Report any movement of the indicators directly to the fleet manager and ensure re-torque is completed. Report any melting of indicators as this could be a sign of faulty brakes or bearings.

The DVSA adds: “Maintenance may be onerous, it may be a costly nuisance, but we are not yet in the age of the maintenance-free CV.

“Look after your wheels and there is a greater chance of them staying where they should be: On your vehicle.”

routeone comment

It’s a preventable incident, so why do vehicle still lose their wheels while out on the roads?

There are many tools on the market available to assist the industry with ensuring adequate safety measures are carried out – such as wheel nut safety products, and it’s up to operators to ensure they are making the right investments to minimise the risks of wheel detachment.

There are many signs that appear for when a wheel may become detached – such as stud hole elongation and corrosion – so it is something that can be picked up on and fixed before a serious injury, or worse, a fatality occurs.

The guide from FTA/IRTE states that when a wheel becomes detached from a heavy vehicle it may simply come to rest without causing any further damage or harm.
However, in the wrong circumstances, when wheels become detached from a moving vehicle, they can accelerate up to around 150km per hour, reaching a height of 50m before colliding with other vehicles or road users at an equivalent force of 10 tonnes.

As DVSA says, “maintenance may be onerous, it may be a costly nuisance,” but at the end of the day, taking the time to carry out the checks and investing in the tools will not only save a firm’s reputation, but also lives.




Cold appears to cause problems as do mis matched wheels and tyres. A scientific study is overdue

Trevor Coltman
The investigation into wheel loss has been on going for many years. Great care is necessary and nuts obscured by wheel trims pose a particular threat.
There is a case for wheelstuds being service items replaced at fixed intervals. Extremes of heat and
Trevor

More like this...


Scania - Deliveries