Hub damaged CV wheels going unnoticed: MWS
Commercial vehicle wheels operating on non-standard spider and star shaped hubs are sustaining damage that could half their lifespan, according to research by Wythenshawe-based distributor, Motor Wheel Service. The company instigated research into the damage non-circumferential hubs can cause to wheels untested on anything other than circumferential products. John Ellis, managing director of MWS, said: “We do not know how many vehicles are operating on UK roads with spider and star shaped hubs. It is now up to VOSA and the main CV bodies, who I suspect are completely unaware of this problem, to ascertain the scale of the issue and exactly how it should be handled.” Ellis and MWS have long campaigned for the introduction of more stringent safety checks on CV wheels, citing the influx of take-off or second-hand wheels into the UK market; now the use of non-standard hubs has provided them with a second angle to present to the Department for Transport.
The investigation was carried out by one of the world’s leading CV wheel experts, Dr Sundararajan of Wheels India, and forms an integral part of Motor Wheel Service’s ongoing wheel safety campaign. His research found that commercial vehicle wheels operating on spider and star shaped hubs are suffering untested load stresses which are causing cracks and halving life expectancy.
At present all quality wheels are tried and tested to European Tyre and Rim Technical Organisation (ETRTO) standards on a circumferential hub with a continuous contact diameter, which is universally acknowledged as the main criterion by the Association of European Wheel Manufacturers (EUWA). However, the introduction of non-circumferential hubs, which give only partial contact between the axle and wheel, is causing localised stresses in the wheel that are almost twice as high as those generated in the use of the industry approved full contact hub.
The repercussions of the research will be numerous, MWS states. Operators will be required to contact hub and wheel manufacturers as products originally replaced or refunded under warranty may no longer be considered if the product is shown to have operated on a spider or star shaped hub.
In addition, interchangeability can be affected due to the differing characteristics of the various hub shapes. Mounting those wheels on hubs with yet another shape can further reduce the attachment area drastically, leading to increased surface pressure and an undefined attachment of wheel to hub.
MWS also argues that vehicle maintenance, service schedules and MOT tests would also need to be more rigorous. The company suggests that operators contact VOSA and the main CV organisations for their interpretation of the findings.
Findings to be presented to the DfT
John Ellis stated that the results of the latest research will now be presented to Mike Penning, under secretary of State for Transport, and senior personnel at the Freight Transport Association (FTA); Institute of Road Transport Engineers (IRTE) and Road Haulage Association (RHA).
Ellis said: “The research is undeniable. Wheels designed and manufactured to ETRTO standards are being placed on axles that are non-standard, or non-circumferential. This is leading to the early fatigue of wheels, primarily displayed as cracks, approximately halfway through the lifetime expectancy…. Time and time again we have told people that there is a problem in the marketplace exemplified by a sharp increase in the number of cracked wheels we are witnessing, I suspect we will see a correlation with the increasing use of these hubs.
“The wheel safety issue is still a number one priority and we will continue to push for further clarification of testing and unregulated sellers. In the interim I urge any operator concerned with the findings to contact VOSA, the manufacturers or MWS and we will help resolve this issue,” concluded Ellis.