New tires and strange handling

[Bill in Bama]

I recently replaced the rear tires on my 2021 718 GTS 4.0. The original Pirellis were worn out while the fronts still have 5-6 32nds of tread left, so I just wanted something to get me by until I could put a full set of new rubber on. I bought a pair of Falken Azenis FK460 A/S XL tires in the original size to get me by. They were pretty cheap as these things go, and I don't track my car so I figured they would do OK. First off, the installer put 42 psi in each tire, which resulted in some strange handling quirks. I adjusted the pressure down to the recommended pressure and it seemed to help. But I've noticed that upon WOT acceleration the rear seems to dart right and left, and this continues after reaching extra-legal speeds of 75-95 mph on a straight road. Wind isn't a factor, but it handles as if a strong crosswind is blowing the car around. Too soft compound? Too much differential between tread depth front to rear? I'm open to suggestions as to how to mitigate this, and what is causing it. BTW, I plan to put a set of Continental DWS 06 Plus on when the fronts wear out.

I don't do the A/S type tires for snow, but for rain. We get a fair amount here in upper Alabama, and while I don't take my car out if it is raining, I sometimes get caught in a storm, and when on trips the weather cannot always be predicted. So since I don't do any HPDE anymore, the A/S performance category appeals to me. I ran Michelin A/S high performance tires on my 981 GTS with good results, except for the abysmal tread wear, which is why I plan to switch to Conti's.

[P_Coastal]

Hi Bill, I am a fan of the High-Performance A/S category as well. Mixing brands or tire specs front - back is not recommended. Lots of people do it and say they are happy with the results. In this case your mix is both brand and category of tires. They are possibly just too dissimilar to work together.

[blueline]

I recently replaced the rear tires on my 2021 718 GTS 4.0. The original Pirellis were worn out while the fronts still have 5-6 32nds of tread left, so I just wanted something to get me by until I could put a full set of new rubber on. I bought a pair of Falken Azenis FK460 A/S XL tires in the original size to get me by. They were pretty cheap as these things go, and I don't track my car so I figured they would do OK. First off, the installer put 42 psi in each tire, which resulted in some strange handling quirks. I adjusted the pressure down to the recommended pressure and it seemed to help. But I've noticed that upon WOT acceleration the rear seems to dart right and left, and this continues after reaching extra-legal speeds of 75-95 mph on a straight road. Wind isn't a factor, but it handles as if a strong crosswind is blowing the car around. Too soft compound? Too much differential between tread depth front to rear? I'm open to suggestions as to how to mitigate this, and what is causing it. BTW, I plan to put a set of Continental DWS 06 Plus on when the fronts wear out.

I don't do the A/S type tires for snow, but for rain. We get a fair amount here in upper Alabama, and while I don't take my car out if it is raining, I sometimes get caught in a storm, and when on trips the weather cannot always be predicted. So since I don't do any HPDE anymore, the A/S performance category appeals to me. I ran Michelin A/S high performance tires on my 981 GTS with good results, except for the abysmal tread wear, which is why I plan to switch to Conti's.

Tire technology is through the roof as you know and the differences between different tires is huge - all the things you alluded to and more. There are so many variables nowadays that I can't begin to list them all even if I knew more than I do with my limited knowledge, but I'll at least scratch the surface.

The many different compounds are often secret concoctions, varying hugely between different models of tires even when from the same manufacturer and even more so between manufacturers.

The highly engineered tread designs are incredibly precise with specific driving styles or temp ranges or vehicle performance and weight ranges in mind, just to name a few of the basic parameters.

In addition, the tire sidewalls and carcass materials and designs are usually wildly different these days between tire models and especially with different manufacturers. Where they're manufactured can have a bearing too - quality and material processes can vary as well as the manufacturing equipment used.

Some brands are just plain crap these days. Stay away from them if safety and performance is a goal.

Remember, Porsche works with manufacturers specifically and intently designing tires exactly as Porsche engineers stipulate for a given vehicle - hence the many different "N" rated tires for Porsche.

Tires are the key for driving safety and enhancement. Period. That small contact patch touching the pavement is the only thing keeping you going where you are intending to go. I would NEVER mix tires on a car like a Porsche - any of them. Never. The handling characteristics and safety are simply out the window. Gone. The fun and satisfaction of driving a true sports car as it was intended to be driven no longer exists.

I also always recommend sticking to "N" rated when possible. If not that, then a high quality tire such as regular Michelins or Continentals (and a few others) will usually be fine. Again, just don't ever mix tires - keep them the same. I also highly recommend changing tires in sets of four. You can rotate side to side on occasion if you want which might help extend wear.

I've had good luck with Continental Extreme Contact tires on an older (2014) Cayenne Turbo we used to have. I've also had great luck with Michelin Pilot Sport 4S tires. I've never been pleased with Pirellis - I don't like the way vehicles handle nor how they wear. Pirellis tend to wander and have squirrely characteristics, at least that's been my experience. On the other hand, the newer Goodyear F1 SuperSport Max Performance Summer (NA0) made in Germany have been excellent in my opinion, at least so far.

You have a gorgeously balanced, extremely well-handling GTS 4.0 engineered by Porsche for driving perfection that begs for the proper tires. You will never achieve that by shortchanging the car with less than premium tires.

My 2-cents Bill.

[P_Coastal]

Has anyone seen a comprehensive listing of N Spec tires?

[Tom]

Tim's probably spot of about the tires, but didn't you also have a similar issue after they replaced your engine?

[Bill in Bama]

Tim's probably spot of about the tires, but didn't you also have a similar issue after they replaced your engine?

Good memory, yes, the rearcwould dart left and right when throttle was applied or released. But that was due to a broken/left off bolt in the rear suspension, and once replaced the issue went away.

Thanks for all the input, I don't necessarily disagree with any of it, except my experience with the Goodyears was terrible, my 981 came OE with them and they lasted slightly over 4000miles.

Before I throw these things away I'm gonna experiment with tire pressure a bit to see if it helps. They are just a temporary measure, because I hate waste and didn't want to put four new tires on when only two were worn out. I did this with my 981, but always kept the same brand, Michelin, although for a while I had A/S rears and HP fronts, no ill effects.

[blueline]

Tim's probably spot of about the tires, but didn't you also have a similar issue after they replaced your engine?

Good memory, yes, the rearcwould dart left and right when throttle was applied or released. But that was due to a broken/left off bolt in the rear suspension, and once replaced the issue went away.

Thanks for all the input, I don't necessarily disagree with any of it, except my experience with the Goodyears was terrible, my 981 came OE with them and they lasted slightly over 4000miles.

Before I throw these things away I'm gonna experiment with tire pressure a bit to see if it helps. They are just a temporary measure, because I hate waste and didn't want to put four new tires on when only two were worn out. I did this with my 981, but always kept the same brand, Michelin, although for a while I had A/S rears and HP fronts, no ill effects.

One guess is that the Falkens and the Pirellis don't play well together. Also, in reference to my comment regarding my experience with the Pirellis that didn't seem stable to me, maybe they are the culprit? Even though your fronts aren't showing wear, it's possible they have degraded and worn in ways that aren't easily seen. If so, they will not perform as expected and could be accentuating the darting you're experiencing. It might not be the Falkans at all. It would be interesting to know how your 718 would perform with a new set of the same Falkens all around.

[Tom_N]

What are your thoughts on A/S vs summer tires in the wet? Better than say a Michelin Sport Cup 2 sure, but what about a Sport 4S or Extreme Contact? I see A/S tires as a compromise, and would not put them on any sport machine I owned. If I really needed winter performance I'd have two sets, summer and winter.

I think the cause of your issue could be due to a compromised tire design that isn't the best of the best, and you've mixed tires front and back.

[blueline]

What are your thoughts on A/S vs summer tires in the wet? Better than say a Michelin Sport Cup 2 sure, but what about a Sport 4S or Extreme Contact? I see A/S tires as a compromise, and would not put them on any sport machine I owned. If I really needed winter performance I'd have two sets, summer and winter.

I run two sets - winters and summers - on both the 992 TTS and the Cayenne Turbo. Not really critical to have winter tires where I live, but I much prefer the cold weather attributes of winter tires with their ability to stay pliable in the cold and better wet/snow traction. Plus, I can hit the road at any time of the year and go wherever I choose without worry.

Any summer tire will require a bit of extra awareness and reduced exuberance when driving in wet or cold. If Sport 4S or Conti Extreme Contact, I would not drive much, if at all, in really bad & really cold winter weather of the sort you will get for many months living in the center of Wisconsin. (I know what it's like for you from my 18-years experience living in MI.)

Two sets is the way to go imo. Porsche's preferred winters that I am using are Michelin Pilot Alpin 5 SUV "N0" for the Cayenne Turbo and Goodyear M+S Ultra Grip Performance Gen 1 "NA0" for the 992 TTS.

Summers for the Cayenne T are Pilot Sport 4S Summers (fantastic tires) and for the 992 TS the OEM Goodyear F1 SuperSport Max Performance Summer "NA0" which I really like so far.

[P_Coastal]

For over 20 years I have mostly had a UHP Summer set, and a Winter set (often Bizzaks). Winters are generally -1” from Summers. When the OEM HP Summers are done sometimes I replace them with UHP A/S. This is an evolving category that is often misunderstood. The current tire technology of this class is amazing. For me this is not used all year, but to extend and make more flexible the summer season. I can wake up to 5 degrees C on July 15th. Prime candidate in the class: