Simple question that is often asked on various RV and car forums.
The problem is that I seldom recall anyone providing a clear definition of what they mean by the word "Quality".
If we look at Wikipedia we find the following:
Quality Assurance, methodology of assuring conformance to specifications
Quality (business), the non-inferiority or superiority of something
Quality (philosophy), an attribute or a property
Quality (physics), in response theory
Quality factor, or Q factor, characterizes a resonator's bandwidth relative to its center frequency
and others.
A quick look at RV reviews in magazines, finds the word "Quality" used quite often, but I do not recall seeing any evidence, cited by the authors, of said "Quality" of one RV being any better than another. On the contrary if we use length of warranty as a measure of overall quality I would suggest that in 2014 most RVs have quality comparable or worse to 1971 Pinto or Vega cars and many of us remember just how bad they were and the low quality of vehicles produced by "Detroit" till "Japan" beat the pants off US manufacturers, much as Korean car companies are doing now with their 5 and 10 year warranties.
Since this is a blog on tires, let’s limit ourselves to that topic. Even here there are obviously different uses of the word. A recent consumer magazine purported to present some observations on the quality of a group of passenger type tires. The definition of what the author meant was not clearly stated but can be inferred by the importance of certain performance characteristics as measured and ranked by the author. If a tire performed better for one specific characteristic such as tread wear, it was judged as being of better quality than a tire that did not wear as well. I would argue that this is an overly simplistic approach and can easily be misconstrued by readers just as a claim of "better build quality" in an RV review is meaningless if the author does not define what they mean by quality or they fail to present any supporting evidence.
With my background as a tire design engineer for a major tire manufacturer for 32 years and after working in the "Quality Assurance" department for 8 more years, I would like to offer some observations on how the term "Quality" is used in the tire industry. This is a complex topic so it will take more than one blog post but unlike some of my blogs there will be few technical terms used and the few I do use will be clearly defined.
After all I want to make this a "Quality Article". :-)
Let’s start with a
definition of the word "quality" in this post as "
Conformance to Performance Specification".
So a tire that meets or exceeds more "measurable" features as identified in its specification, would be considered to be of better quality than another tire that did not measure up as well for all of the same set of specifications. So what might a list of specifications include? One of the first tasks a design engineer has, is to ensure they understand what the customer wants.
Lets look at a partial list of what might be presented to the engineer. Some performance specifications are very clear such as:
"
Pass every government Regulatory test by at least the margin established by company statistical margin as published in Standard Practice". This quality standard is a must-do. The Pass/Fail levels are published and easily measured using standard tests with conditions for speed, inflation, load, and distance set down in test manuals.
Some other performance specifications are relatively easy to measure so the engineers know if the tire they designed passes or fails to meet the spec and by what margin they pass or fail to meet that particular goal. Some examples of these objectives might be:
"
The tire is to weigh no more than 32.5#."
"
The High Speed rating will be no less than 75 mph as measured on Society of Automotive Engineers test ABC".
"
Rolling Resistance Coefficient (RRC) shall be 0.234 or lower on SAE test XYZ". ( RRC is a measure of fuel economy)
"
Cost level shall be no higher than 90% of the reference tire as measured by corporate cost dept."
Others specifications are a little or a lot harder to quantify such as subjective performance
"
Steering response shall be judged better than the reference tire".
"
Noise shall be better than the specified reference tire".
Part of what makes these performance specs hard to quantify can be seen by looking at the noise evaluation "report card". Some vehicle companies have 10 or more different noise features they may consider important with terms like "
Braking Growl",
"Expansion Joint Slap", "
Smooth Pavement Sizzle" and similar. Even Steering Response is complex with both "
On Center Feel" and "
Linearity" being a few of the items being evaluated for steering response. We don't need to go into the details of these evaluation features as that would be a post topic unto itself, but you can see these items may be difficult to rate as they are all subjective.
One challenge for the engineer is to get the vehicle evaluator to rank order all of these various performance characteristic. Many times what we get is "They are all important" so how would you judge the conformance to specification if tire X was rated a +1 for "Expansion Joint Slap" while being rated equal in all other categories to the referenced tire but tire Y was rated a +1 for "On Center Feel" while being rated equal in all other categories to the reference tire? Which tire is the better Quality tire? I think the obvious answer is that despite claiming that all characteristics are "equally important" the evaluator really does have a preference and uses that preference to give the edge to one of the two tires being evaluated.
So why is this all so important? Well in the example of the consumer magazine rating the quality of some tires better than others I think they missed the point that not all tires are designed or even intended to meet identical performance specifications.
Next time we will look at why all tires are not designed to the same Quality Standard and what you can do to try and get the Quality you want in your tires.
Subscribe to the weekly RVtravel.com newsletter or one of our other
newsletters about RVing. Great information and advice. Now in our 14th
year.
Learn more or subscribe.
“US brand name” stamped on them, leaving the consumer with very few, if any, alternatives.
Now, coïncidentelly, we hear that LT tires are “just the thing” for trailering.
It also appears that a handful of RV manufacturers, like Jayco, have seemingly struck a deal with Goodyear, who now has resumed manufacturing ST tires in North America, to equip their new trailers with “US-made ST tires”. I guess their ST tire prices have dropped again enough to catch the big manufacturer’s attention and make it worth their while.
So I guess the real question should now be, are US-made Goodyear ST tires better, worst or equal quality than their US-made Goodyear LT tires, or why even bother to engineer ST tires at all? We shall see, in time, who wins between; Beta or Vhs, Plasma or Lcd, Android or Apple, etc, etc, etc."
Alain, The biggest issue is, I know of no way to do a direct comparison of ST vs LT tires other than an expensive tire test. We can't depend on the DOT test results. In all probability the tires all pass, simply because the RV industry and ST tire mfg companies were successful in getting ST tires excluded from the significant improvement in testing with updated standards in 2002. There is no question, in my mind, that the tests (FMVSS 571.119) for ST type tires are easier to pass than the tests (FMVSS 571.139) for new Passenger and LT type tires.
I have looked at the construction of a GY Endurance and it certainly looks better than the older Marathon design. Now remember I do not have access to the actual specification or material properties used by GY but in the Endurance tire line, they appear to have added a Nylon cap over the steel belts. You can confirm this by reading the material list molded on a tire sidewall.
"Quality" is a tough call when you have two different specifications to start with. Isn't Quality just a measure of a tire's ability to meet the specification for that product?
You can think of it this way. If I had two pieces of chain. One rated at 500# and another rated at 550#. They both meet a strength test of supporting the rated load and if you tested 100 pieces of each and found that all 100 passes the rates strength test how would you rate the 'Quality"? You can't say the 550# chain is better quality than the 500# chain as they have two different goals, just as you can't say a 1-ton truck is better quality than a 1/2 ton truck because the 1-ton can handle more load.
Your example of Beta vs VHS is a good example of the confusion possible. Beta was judged technically superior to VHS but Sony made a marketing decision to prevent other companies from using the Beta specification in their video players. The result was that VHS units were less expensive so many people bought on price. Eventually, Sony lost out. Not because the "Quality" of that video format wasn't as good as VHS but because the market was "price-sensitive" and too many people selected lower cost over better quality product.
Gene offered
"OK, color me confused! I have always gotten the impression that ST tires and not LT tires are what I should be running on my RV. After reading this article now I’m not sure. Are you suggesting that all things being equal, LT tires of the same size, load rating, etc are better to run on my RV? I don’t mind the cost, just want to put best possible tire on my RV. Thanks for keeping us informed."
to which I replied
Gene, The problem is that "all things are not equal" as there are no LT tires of the same size, load range, and load rating, etc as an ST tire. There is always something that is different.
Sometimes the only option would be to go with larger size LT tires but in some cases, there is no physical room to run the available larger size tires.
IMO, what you "should" be running are tires built to the latest industry test standards (LT) that can offer at least 15 to 25% "Reserve Load " capacity