A simple question with a huge diversity of possible responses, of course, and I guess the response from any one individual will be largely determined by that person’s philosophical perspective.
If we summed everybody’s responses we’d no doubt decide that governments should do basically everything for everybody. So the question then becomes – what are governments capable of doing giving all the constraints placed upon them?
Some might argue that governments can and should ‘keep us safe’. Hard to argue with that. But how far does their safety responsibility extend? Is it reasonable to expect law enforcers to stop criminals? Surely. But can governments stop me falling down the stairs at home? Of course not. These are of course two ends of the spectrum, and somewhere in the middle is a position at which government responsibility logically ends, with the responsibility for safety then passing to others.
And I’d argue pretty strongly that responsibility for tire safety falls clearly into the latter category. Sure, governments play a role through the requirements of legislation such as FMVSS, JIS and ECE. But as a group of people who understand tire durability much better than the average punter, we’d surely be kidding ourselves if we thought we could in any way rely on the results of those tests as a ringing endorsement of designs, or even a vague indicator of the long-term durability of a large population of tires on the market.
I’m sure we’re all very familiar with the manufacturing variables that will affect the durability of individual tires – contaminants, raw materials variances, variations from specification in individual component manufacture, in component placement (eg. ply, belt and tread centrality), in the storage conditions and duration of components, and in curing variables – to nominate just the obvious ones.
Sure every manufacturer has the best of intentions and many take every possible step along the way to minimize the chance that something will go awry in the manufacturing process. Though despite the ‘best made plans’ we all know that – occasionally – we will end up with products that fall somewhat short of their design durability level.
It’d be drawing a very long bow to argue that FMVSS, JIS and ECE durability test methodologies would even hope to capture these variations. Indeed, three very basic characteristics restrict their applicability to their original intent (which was to prevent very poor designs from making it onto the market) – the sample size, the test conditions, and the lack of a longitudinal requirement.
The double tread curvature of a test wheel footprint notwithstanding, it’s blindingly obvious that a sample of one or two tires tested for a short duration in tightly prescribed laboratory conditions, often years before, cannot represent large populations of product thereafter manufactured.
And we don’t have to look very far for proof of our vulnerabilities – there have been more than 80 tire recalls in North America in the past five years alone, most for durability-related issues, and ALL of tires whose designs were approved under the relevant legislated standard QED.
It’s not realistic to expect governments to prescribe tire durability testing regimes that might protect the whole population. Indeed, I doubt that’s what any of us want.
Hence, in their absence, it is incumbent upon us all to ensure appropriate control of tire manufacturing variables is confirmed through longitudinal laboratory and in-field test procedures to monitor product durability and safety. Lives depend on it.
David Southwell is an independent consultant to the tire industry. He has more than 30 years’ experience working with automotive OEMs in design, development, production, quality, technical training, field performance and failure analysis roles with various tire manufacturers and retreaders in the Asia-Pacific region. Southwell’s expertise spans passenger car, light truck and truck and bus tires, and he holds a master’s degree in engineering.
David Southwell, independent tire consultant and failure analyst, Australia
