Quote:
Originally Posted by lucid
The authors of Going Faster most likely know more about driving on any kind of tire on a race track than you, I, or anybody else on this forum ever will. You asked for test results, I referenced their test result. Now, you're saying they don't know what they are talking about and their tests are not scientific. The test procedures are indeed not documented, but I'll buy their test results over any "opinion" expressed here any time.
Moreover, they bring up street tires because they seem to have racing experience with them!
"For the Spec Racer and Skip Barber Formula Dodge 2000 series, there are multiple reasons for preferring street tires to slicks. Safety and durability are high on the list..."
I don't think they run street tires in any of their current series though. However, their Formula 2000 racing school cars are on street tires. So, your dismissal of their expertise is perplexing.
And, if you really think the opinion of the average enthusiast serves as proof that decreased tread depth decreases traction, there are two people here who reported no "major" issues with grip on PS2s at the bars, and we've got the guy I know who turned faster laps at LRP on PS2s at the bars that were stashed away for several years than he did before when they had more tread despite not so significant loss in traction. As I said, the "significance" of the loss of traction is a subjective consideration, so opinions will not establish much either way. What we are discussing is if and how tread might be related to the loss in traction (as in the title of this thread "traction vs tread depth"), not if there will be a loss in traction (we've been over that and everyone agrees hardening will decrease traction).
Skip Barber manual says time is a factor, but it also says the effect is primarily experienced up front--that there is a noticeable drop in traction after initial use and the effect of time then somewhat stabilizes. So, they are not claiming a linear relationship there.
The UV exposure is more straight forward. Cars that experience tread wear must, by definition, experience exposure to the elements unless one wears the tread down on a dyno in an insulated garage. So, if UV exposure (and compound hardening) is the cause, the tread depth correlation can indeed be meaningless for the most part.
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The experience nor skills of the authors is not in question. Great driver however does not always equate to great observer. Drivers and racers probably do their fair share of perpetuatation of myths. Why might that happen? Fairly obvious - without the big bucks science/engineering behind really well funded types of racing this can happen. Come on you are a scientist as well, tell me that you haven't found something in this book that you are fairly certain is not correct? It is not gospel.
Next without looking at the book it is hard to say, but to call what they did as testing or scientific (as opposed simply to limited anecdotal evidence) is almost for sure a huge exaggeration. I will not set aside my observations and the identical observation of others herein without much stronger evidence than that.
I am really quite surprised you have not experienced the same effect. More have chimed in that they have (even discounting confounding wet and cold effects).
I am not sure what you mean in the your last comment. My point was this: tread wear depth and UV exposure will always be correlated but the level of correlation can vary dramatically. If you drive the hell out of your car with lots of track days and combine that with a less UV intense area vs. then consider opposite of all of those things I suspect you could go from an decided observation of UV hardening effects vs. nearly no effect from it.
Lastly the traction I am getting from your used rear PS2s is substantially better than my entirely worn ones. They are much more resistant to slipping and spinning and first and do not give nearly as much/as easy chips under WOT shifting.
Lastly I have never been claiming that traction decreases linearly with depth or something of the like. Perhaps that makes the title of the thread ever so slightly inappropriate to describe my observations. But I think I have made this point quite clear.