Thanks, CapriRacer,
For being here to help out. That last post was very helpful.
I have been studying the presentation by Lambillotte. Can we see the full test report? The slide show just has too much information missing. And, if the raw data are available, I'm sure we can coax more information out of it. I don't need manufacturers' names, just data by product line.
About the chart on page 31--it clearly shows that larger tire sizes are more efficient. (This is consistent with the widely-known fact that rolling resistance decreases with increasing tire diameter.) But, we need more information about the test conditions such as tire pressure, loading, tread and sidewall thickness, and other variations in the tire construction.
Smithers may be a respected testing company, but it's apparent they don't know what to do with the numbers they have. It's regrettable that this work had so little oversight or peer review.
By the way, I find it almost humorous that the data we have all been asking for has already been collected by Smithers.
Quote:
Originally Posted by CapriRacer
Ernie,
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The problem isn’t consistent results or controlling the right variables. We’ve been at this for over 30 years and we can consistently get repeatable results – except that there is a problem that is best explained by looking at page 31 of this:
http://www.energy.ca.gov/transportat...%20Testing.pdf
Page 31 is the RRC for a range of sizes, but they are all the same tire line. Bruce Lambillotte has paraded different versions of this data around the tire industry and one time he revealed that the tire line is Goodyear Integrity.
This is the problem you alluded to. There is a 30% variance best to worse for the same tire albeit in different sizes. The test is a standard RR test using standard conditions – all tied to the same load table. This is as consistent testing conditions as can be made.
For background, Smithers is a well respected tire testing company.
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