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GC4 Lunch:
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.....The difference between an all season tire and a non all season tire is in the tread compound......
I was hoping you meant tread design, not tread compound, but reading the rest of that paragraph it is apparent you didn't.
Nope, you read me correctly the second time.
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Snow traction - what makes it an all season tire - is driven primarily by the tread pattern. Tread compound has very little effect on snow traction.
In fact, the standard that is used to define an all season tire is a written description of the characteristics of the tread pattern. The tread compound isn't even mentioned.
Pirelli P Zero Nero M+S, an all season tire
Pirelli P Zero Nero (full stop): not an all season tire.
The tread patterns are
identical. The compounds used for the treads, however, are very different. The all season tire has a much higher treadwear rating and a much longer wet braking distance.
(now discontinued) Pirelli P7000 Supersport: an all season tire
(now discontinued) Pirelli P7000: not an all season tire.
The tread patterns are
identical. The compounds used for the treads, however, are very different. The all season tire has a much higher treadwear rating and a much longer wet braking distance.
There are many other examples of pairs of very similar (though not identical) tread patterns in manufacturers' line-ups, where one tire is an all season tire and the other is not.
There are all season tires with large tread blocks and all season tires with small tread blocks; there are non all season tires with large tread blocks, and there are non all season tires with small tread blocks.
There are all season tires with long, uninterrupted tread grooves; there are non all season tires with long, uninterrupted tread grooves.
There are all season tires with directional tread patterns; there are non all season tires with directional tread patterns.
There are all season tires with asymmetrical treads; there are non all season tires with asymmetrical treads.
In fact (with the possible exception of over-siping, which is common, but not universal, in all season tires but very rare in non all season tires), I think you cannot name a single characteristic of tread pattern (or any combination of characteristics) that distinguishes an all season tire from a non all season tire.
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....There is no technical reason why all season tires generally should have higher treadwear ratings than non all season tire, but there is a marketing reason.....
At first I was going to disagree, but reading the rest of the paragraph...
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....... The tire manufacturers assume that the primary factor in a purchaser's decision to purchase all season tires is that the purchaser values price over performance (if the purchaser wanted performance, he or she would have a second set of dedicated winter tires, and swap tires twice a year), whereas the purchaser of non all season tires generally values performance over price. Treadwear is, of course, a factor in price, and generally is easily achieved by making the tread compound harder. Performance generally is achieved with softer tread compounds, however.....
If we confine our descussion to three types of tires - all season, winter, and ....oh.....some folks call them "summer" tires,
A quibble: I think that in the current market, there are four types: winter, all season, "true summer," and "3-1/2 season" tires. Admittedly, this
terminology is not used, but it reflects the "facts on the ground," as Donald Rumsfeld used to say. That is, within the category of "summer" tires, there are two very different groups of tires. Compare, for instance, the Yokohama ADVAN Neova and the Yokohama ADVAN Sport. The Neova is a tire designed to be sticky, with extremely high performance, at high operating temperatures and, while a street tire, it is suitable for light track use. However, at lower temperatures (below 40 degrees F., and really below 50 degrees F.), its tread is hard and the tire gets quite goosey. The ADVAN Sport, in contrast, has an exceptionally wide temperature operating range, staying pliable and flexible to well below freezing. In fact, we have ADVAN Sports on our own car, and I have found it to have very much superior traction in temperatures at least 15 (F.) degrees below freezing to Michelin Pilot HX MXM4 sll season tires.
That is why I am reluctant to call non all season tires "summer tires." There
is a subset of non all season tires that really are summer-only tires, but
most non all season tires, having tread compounds that are much softer than all season tires' at -- say -- 40 degrees F., are better-performing at -- say -- 20 degrees F. than all season tires are. (The tread compounds of all season tires that are hard at 40 degrees get even harder at 20 degrees.) So those latter non all season tires are better winter (though unsuited for snow) tires than all season tires are.
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If we assume that 2 tires are identical in all respects - except for the all season part, then a summer tire will generally give better wear, because the tread patterns are simpler. But only slightly better.
However, most of the time the tread compounds in an all season tire wear better - at the sacrifice of traction.
As I note above, though there may be more non all season tires with large tread blocks and more all season tires with small tread blocks, there are all season tires with large tread blocks and there are non all season tires with small tread blocks. I think that the reason that the majority of all season tires have high -- some -
very high -- treadwear ratings is that the tire manufacturers, recognizing that their target purchaser wants long wear, make them with very hard compounds, which has a significant negative effect upon their handling and braking performance, also.
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I know you are an advocate of winter tires and - as you call them "3 season" tires - and I happen to support you on this - but I think we have to recognize that most folks don't like to change tires, plus they want the tires to wear well, so all season tires is what they want and what they are comfortable with.
I think we are in full and complete agreement on this. For the average tire purchaser, the first five most important factors are price, price, treadwear (when do I have to pay that price again?), price, and treadwear -- and braking take the hindmost.
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Just so you don't misunderstand me - I am lumping both hydroplaning resistance and pure wet traction together under the umbrella "wet traction".
Understood. As you know, my take on the subject is that hydroplaning resistance is
very important, but only a
very small percentage of the time, when the standing (or flowing) water on the roadway is deeper than the tread groove depth. At those times, the Utopian in me says: reduce speed. The very best anti-hydroplaning tire ever made is quite inferior in resistance to hydroplaning to a very ordinary, everyday tire on a vehicle traveling 15 mph slower than the vehicle equipped with the good tires.