Tires: All Season/Winter vs. Summer/Winter

[cityhpper]

Very interesting post, but I don't think you have fully captured all the factors that make a tire resistant to hydroplaning. So, just to be clear: is it your opinion that winter tires are better suited to avoid hydroplaning than dedicated summer tires? Based on the sipes in the tread blocks?

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[Jonathan S.]

Porsche Westwood ... they had a chalk CT4 that I was sold right after I test drove it and the SA then called me that they had a CT4 on order, fortunately with a fantastic spec.

Glad to hear that worked out so well for you!
I had contacted Westwood yesterday about a used CT4, but it appeared to lack the Technology Package, and now the listing has disappeared anyway.

I wonder if lucking out with an available allocation is easier given that each dealer's waiting lists are split up, let's see, here, what is that ... ten different ways.
(By contrast, for the BMW i4 I'm also looking into, only three different waiting lists at each dealer.)

unlike ICE vehicle's range is deeply affected by tire choice. [...]

Same % hit via rolling resistance, but nobody cares (or at least not much) when ICE MPG drops by, say, 10% and hence cruising range drops by 10%, yet that same 10% hit on MPGe is far more noticeable when EV range is down by 10%.

Fair question! I realize I really just made a statement there without any kind of reasoning to why that would be the case. The reason comes down to the tread pattern. The technical term is tire siping, which is really a fancy word for the cuts and patterns in the tire. All other things being equal, (size, materials, etc) a tire with more cuts across the tread design can evacuate more water from underneath itself when it enters a puddle. This is how a tire prevents hydroplaning. Hydroplaning occurs when there is more water under the tire than the tire can handle, causing the tire to float above the water and lose contact with the ground.

[...]

A summer tire has very few cuts across the tread design. This is to maximize rubber to road contact in performance scenarios (like doing a vegas to red rocks canyon run) where the all season tire has a more heavily cut pattern. This results in a more 'squishy' feeling tire but is much better at removing water. You can also see that winter tires take this even further. Not pictured, off road/all terrain tires take this to an even further extreme, leaving big fat gaps between the road contact points of the tire. [...]

For winter conditions, yes.
But for wet conditions, I'm not seeing it in the results:

• Nordic / Studless winter tires (i.e., as opposed to Central European / Performance) have the most siping, yet also the worst performance in wet conditions. (This is a big problem in New England, where our winters often feature rain, or just very wet slushy conditions, and hence Nordic / Studless winter tires are a poor choice for most drivers here, despite their popularity.)
• I looked at the Consumer Reports tire ratings (yes, I know that their car ratings have their detractors, including myself, but their tire tests seem far more quantitatively focused and legit) for summer tires (top choices from them are Michelin Pilot Sport 4s and Continental ExtremeContact Sport 02) and their highest category of all season models (topping the chart are Michelin Pilot Sport All Season 4 and BFGoodrich G-force Comp-2 A/S plus), which show no difference across the two categories for the ratings of Wet Braking and Hydroplaning (although plenty of difference within the two categories across models in the wet, but almost all of them are quite capable in the wet).

 

[blame.latitude]

Siping isn't the only factor in tire rain performance, but it's very important in my personal experience. I had Michelin Pilot Sports on my M3 for a while. They were amazing when new, but after a few years they became to feel dangerous in the rain. That car's rear wheel drive with no traction control, so I could really feel them when they slip. I drive it in all conditions except snow. Now I have the pilot sport all seasons. Having driven them in all conditions I feel more confident in all seasons. Feels much more planted on the ground. For where I live (Vancouver) and the weather I get I feel better on those. Perhaps it's a different calculus if you are in a tropical location.

I do wonder about those tire tests as well. Are they saying that the PSS4 is extremely good in the rain 'for a summer tire', or is it an absolute measurement of wet weather performance? It's really hard to say.

 

[Jonathan S.]

You definitely experience lots of wet weather living in Vancouver!

But was the drop-off in summer tire performance just because you were low on tread?
Summer tires typically have very short lives, so I'm surprised yours last a few years, even if run only a few months each year.

I'm pretty sure the Consumer Reports ratings are the same across all categories, not within each categories. That is certainly borne out by how most (but not all) tires within a category perform roughly as expected. (For example, no all season tires get the very best ratings in snow & ice, and no winter tires get the very best ratings in wet conditions.)

This test is probably the definitive word, running different types of Michelin tires in the same conditions against each other:
https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=270

May 24, 2021

Tires Tested
Michelin Pilot Sport 4S(Max Performance Summer, 225/50R17 (98Y))

• What We Liked: Crisp steering, on-road refinement, impressive wet traction.
• What We'd Improve: There's some frustrating mid-corner understeer in the wet.
• Conclusion: The quintessential Max Performance Summer tire.

[...]

In the wet, the Pilot Sport 4S once again led the field in lateral grip, average lap time, and in our testers' subjective ratings. The only minor complaint our team had with the tire's performance was some mid-corner to corner-exit understeer that could result from too much speed, too much steering input, or too abrupt steering input. The turn-in was crisp, and the vehicle obediently followed to the apex, but it would push wide unless the driver got it right. Other than that quirk, our team found nothing to critique. The traction was very strong, the steering was precise and responsive, and the braking was impressive.

 

[blame.latitude]

I see the review, but it doesn't align to my lived experience. I mean, your posted review literally says the PS4S understeers in the rain. Besides that,you seem to be discounting tread pattern entirely. The pattern makes a huge difference. That's why I only run all seasons for where I live.

Tread Matters: The Science Behind Tread Patterns (tirereview.com)

 

[Jonathan S.]

True, that summer tire model was far from perfect in wet conditions, but those Tire Rack reviews are quite exacting for handling evaluation, and no tire is even perfect for anything in their subject evaluations.
But more importantly, glancing through their various summer tire model tests, clearly summer tires are not any worse as a category in wet conditions -- warm *and* wet conditions that is.

As for tread pattern, that article was an interesting read, thanks. However, it doesn't address the seemingly counterintuitive result that Nordic / Studless winter tires, which have the most aggressive open tread patterns, perform the worst in wet conditions. I've never read an explanation of that, but it's an overwhelming finding in all the objective tests. And it can't be the softer winter compound, since Central European / Performance winter tires with softer compounds are far better in wet conditions (although as a category still not as good as higher-end all-season tires).

Either way though, we're definitely in agreement on the limited utility of summer tires for anyone who lives in a climate where even fall and spring feature mornings and nights that are too cold for a summer tire compound. But my understanding is that they're still great for a place like, say, Florida, that is [almost] always warm enough for summer tires, yet also receives rain.

The other drawback of summer tires is vastly shorter lifespan. I wonder if your summer tires still had enough tread for good performance on dry roads, yet no longer enough for wet roads?

 

[DougFrisk]

What I know is that when the factory tires wear out on my wife's new 4CT they'll be replaced with Michelin Cross Climate 2 tires. They are all season tires that are severe snow service rated that are better in the snow than many dedicated winter tires I've used.

I'd love to see Porsche offer them as OEM tires, but they're V speed rated so only usable on the base Taycan or the Tacan 4CT.

 

[Jonathan S.]

What I know is that when the factory tires wear out on my wife's new 4CT they'll be replaced with Michelin Cross Climate 2 tires. They are all season tires that are severe snow service rated that are better in the snow than many dedicated winter tires I've used.

I'd love to see Porsche offer them as OEM tires, but they're V speed rated so only usable on the base Taycan or the Tacan 4CT.

Same here -- well, once I get a 4CT.
I do though have those tires on my Audi A6 Allroad and can attest to their winter performance.
But they do have a noticeable MPG hit, so expect the same for MPGe and hence EV range.

 

[Archimedes]

If you’re going to be driving in or around freezing temps often, run all seasons. If not, run summers. The grip difference is noticeable on turn in, and wet weather performance is still good given current tire compound technology. Wet weather grip isn’t only about siping, as the compound is equally important. I’ve run Dunlop Race 2s hard in mid 30s and they still stuck like glue. You’ll be fine on PZeros.

 

[WasserGKuehlt]

Fair question! I realize I really just made a statement there without any kind of reasoning to why that would be the case. The reason comes down to the tread pattern. The technical term is tire siping, which is really a fancy word for the cuts and patterns in the tire. All other things being equal, (size, materials, etc) a tire with more cuts across the tread design can evacuate more water from underneath itself when it enters a puddle.

This is partially correct; siping helps with traction on low-friction _solid_ surfaces - ice, snow etc. - but not through standing water. In that case all you need is the capability to eject a large volume quickly - so deep channels, with the right orientation and shape. Winter tires are, in fact, worse in plain-rain than the equivalent all-season, precisely because the siping doesn't do anything to channel water away from the contact patch.

As to why an all-season may be better than a summer wrt aquaplanning: just depth of tread/channels in the tread. A wider channel means a smaller effective contact patch, and a deeper (but narrow) channel means the tread itself is more flexible (and so imparts the vehicle a vague steering/grip feeling).

 

[Vercingetorix]

And it can't be the softer winter compound, since Central European / Performance winter tires with softer compounds are far better in wet conditions (although as a category still not as good as higher-end all-season tires).

I remember reading years ago that a compound that grips well in the snow is diametrically opposed to one that grips well in the rain. You can’t optimize for both, there will always be a compromise. I think silica was the reason, but it was a while back and I’m sure improvements have been made.

 

[Jonathan S.]

I remember reading years ago that a compound that grips well in the snow is diametrically opposed to one that grips well in the rain. You can’t optimize for both, there will always be a compromise. I think silica was the reason, but it was a while back and I’m sure improvements have been made.

Hmm, that reminds me, although so many on-line posters often say, "Get Blizzaks!" without regard to the major differences between their LM vs WS lines, I remember that the Blizzak LM Central European / Performance tires have a uniform compound that is essentially the same as the underlying layer of the bi-compound design on the WS Nordic tires. So perhaps that explains most of the wet conditions performance between the Blizzak LM vs WS lines?
And I wonder if a test of a Blizzak WS model once it has worn past the initial compound would show improved performance in wet conditions despite the worn-down tread?

 

[Vercingetorix]

I am going to run PS4s once my Procontact RXs wear out. If I was to live in a place that got 10 more days of snow a year the Bridgestone LM005 would be my choice, only because they do so well in the rain. Making a good snow tire doesn’t seem to be terribly difficult. Making a good snow tire that does well in the wet and well when worn down seems to be black magic.
https://www.tirerack.com/tires/tire...0LM005XL&vehicleSearch=false&fromCompare1=yes
https://www.tyrereviews.com/Article/2022-Tyre-Reviews-Winter-Tyre-Test.htm

 

[ben1]

What about the option of driving all year with winter tyres ?
Is it a really stupid idea ?
Are they really that bad in summer ?

Winter tyres last a bit less long in summer temperatures and the consumption is a bit higher, but that is probably balanced by having no labor cost for switching tyres 2 times per year.

I did it on my previous car because I was too lazy to switch the tyres 2 times per year. Did not have much problems with it. But I am not an expert at all.

 

[Vercingetorix]

What about the option of driving all year with winter tyres ?

May as well drive a Dacia Sandero.

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