By Roger Marble
I continue to see people talking about “China bomb” tires. As an engineer, this makes me a bit sad that so many people appear to have such a poor understanding of the difference between “causation” and “correlation.”
It is true that a majority of the tires on RV trailers that fail were made in Asia, and for many folks that means “China.”
But I would ask: If 90+% of the tires applied to RV trailers were made in “China,” why are you apparently surprised to learn that 90+% of the tires that fail in RV trailer use were made in “China”?
In an effort to make the difference between “causation” and “correlation” a bit easier to understand I have sometimes offered the following example.
If you check with people in prison you will probably find that 90+% have eaten McDonald’s fries. Therefore, it could be concluded that eating those fries can be considered something like a “gateway drug” to breaking the law and ending up in prison. I think we can see that that conclusion is not sound or reasonable, but clearly the numbers are similar to what we see in the RV community.
Yes, tires on RV trailers have a shorter life than in other applications, but the major reasons for the higher rate is clearly a combination of factors. Those factors include the documented very high percentage of RV trailers with tires in overload/under-inflation condition, as well as the clearly identified impact on belt separations due to Interply Shear due to the suspension design of multi-axle RV trailers.
Read more from Roger Marble on his blog at RVtiresafety.net.