[WhiteMale]

I have the PA4 on my car now on the 1LE OE wheels, 275/35 front and 285/35 on the rear. I've actually been quiet surprised at the dry grip and performance on these tires. They are in deed an almost totally different animal but I don't really experience what you're describing. It is easier to break loose the rear but i've been quite surprised at the ability to (still) slam it in to 3d @ 55 and aggressively pass cars.

Your alignment check was all in the green? My car had been toed out pretty bad from the factory and wore out the SC3's sooner that intended on the front.

as to squishy tires I've run the Xi3 studless winter and that was a squishy tire, hated it on anything but snow. I ran a 245/45/19 on a Mustang and avowed to never use that tire or type of tire again, the thing was all over the place and I only need some snow capability 5-7 days a year.

[TRZ06]

Consider this...

Stock 1LE tires have minimal tread depth to begin with, winter tires have A LOT of tread when new.

Tread squirm is very real in most new tires (even more so on winter tires as the key is wet/ice traction) that are not super high performance or not shaved.

This tread squirm causes instability in high straight line acceleration and quick transitions.

You add on top of that a more narrow rear tire than stock and what do you expect?

[WhiteMale]

Tread squirm is real, too. But again I don't notice in the PA4 like Ive previously experienced.

[Alpha1BC]

Originally Posted by Tubtub

Alpha I'm not dismissing what you're saying because you have good points but I think there's another factor at play here. I have a suspicion this wouldn't be as bad of an issue if I used oem sizes for my winter setup. But who knows.

I totally get the tires are going to flex more and seem less sturdy upon hard acceleration vs oem summer, but still shouldn't be so bad. And I don't remember them being this bad the first season I bought this winter setup. Idk

I've actually driven the exact same tire you have in OE sizes as well as a 295/30R20 rear with OE front and done stuff like what you're saying and more and it always felt fine to me at least, even a little above the 40 deg ambient point. There is a bit more wiggle and I could see how that could feel unsafe without having experienced it regularly but it was never anything I'd have considered unsafe. That said, I was never on a truly square setup and in my experience going square or messing with the distance-per-rev on these cars doesn't always play nicely with controls systems and seems like it gets worse the further away from stock you get. You'll activate the controls systems more than you do on the summers, too. Those changes combined with the extra softness and lack of grip from the winters could be causing it, but not having any experience on those specific tires I can only speculate as to what's going on.

Keeping in mind all the controls systems are tuned for stock tires, it makes sense that the rear can get looser. The systems aren't tuned to be tight enough to catch it right away and can even build on itself and get out of control if the driver doesn't reduce throttle. Conversely, if the controls systems were tightened up to catch the slip from the snow tires, it'd be a bore to drive stock without turning everything off because you'd virtually never be able to slip the tires.

As for Dave's being OK, I'd guess it's probably because the 265/40R19 diameter is slightly larger than stock instead of smaller plus it's not as far off percentage-wise from stock as a 285/35R19 so TC is more likely to inhibit a wheel flare that allows the sideways travel which is when the lateral grip would come into play. Either that or you got unlucky and found a specific tire/size that just doesn't work with the controls cals

My next suggestion if you're trying to troubleshoot would be to try a different rear tire that's closer to stock, maybe like a 295/35R19? If you're able to do that and it doesn't make it any better, maybe even finding a big open space where it's safe to feel the limits of the controls systems before they intervene might make it feel more comfortable to you? Not trying to insult you in any way with the last statement, I have just been fortunate enough to be able to work in the field a bit so I know that what feels safe to me for controls systems at the limit might not necessarily feel safe to everyone if they haven't spent a bunch of time around it in controlled environments, and not knowing your background at all I'm only trying to be fully-encompassing in case that it lol.

[Mountain]

Originally Posted by Tubtub

Mountain thanks for joining in. I only have my winter tires on in the winter, the 80 degree comment was a hyperbole to basically just say temp doesn't matter I have found, it always happens. Haven't changed a thing cept cold air intake. air pressures are 32 cold.

It is slightly less noticeable with track mode on, stiffening up how much my back end is allowed to swing back and forth.

Hmm, try running them with a few more psi, maybe more like 34psi and see if that helps. Air them back down to 32 if you get a lot of snow.

The problem posting something like that on here is 1. no one really understands you knowledge/competency, so that becomes a factor in this all (no offense) and 2. no one here is actually experiencing your issue (IOW, they aren't test driving your car) so it's difficult to understand real issue vs. normal/"not" and issue.

Application of a 285/35R19 Alpine PA4 seems OK to the Camaro:
1929lb load rating
https://www.tirerack.com/tires/tires...A4XL&tab=Specs
"Pilot Alpin PA4 tires feature a full silica-based, sunflower oil-enriched Helio Compound+ tread rubber that remains more flexible in low temperatures for better traction in cold conditions. This compound is molded into an asymmetric tread design that features a heavily grooved tread pattern, Michelin's high-density Stabiligrip 3D sipe technology and wrap-around shoulder designs to enhance acceleration, braking and handling."
Translation = this tire is design-optimized for very low temperatures and to allow evacuation of water away from the tread surface and keep grip on ice.

[Tubtub]

Thank you all for the ideas and contributing, I really appreciate it. I would seem to think that everyone is a little bit right here, and it's probably a combo of all of these things. To answer you Alpha I've been dealing with this issue for about a year now and I'm used to what it does and how it behaves, it does feel unsafe. I am used to the consistent way this car behaves normally with summers as I have tracked it autox, road courses etc. I'll just be more careful.

In the end if I could do it again I would have gone with stock size wheels and tires and paid a lil more because I do believe that is the biggest contributing factor. Nannies/tech don't understand what I did. That's just my 2 cents, but my knowledge is limited. Besides the obvious softer compound, higher sidewall.

I think many people probably wouldn't see this as big of an issue as me but I am an aggressive driver most of the time. Everything else about these winter tires is fantastic besides the "oscillating".

With that said I would say, if you want your car to be as badass as possible even in the winter, and you live that 1le life (if you know what I mean), don't mess with stock wheel/tire sizes. Unless you really know what you're doing or are just some chump that drives like a grandma and don't bleed performance like my crazy ass.

[Tubtub]

And mountain I like that idea of the higher psi, I will try that thank you.

[Tubtub]

Trz06 probably right on!!!!

[Tubtub]

Thank you guys, you guys are all great and I now feel much better about all of this with your input!!

[Tubtub]

Active diff probably getting confused too? With the extra squishiness and tread squirm and diff wheel/tire combo? I should have expected that a performance car would have issues if I slice off an inch from the wheels on the rear.

[Tubtub]

I wonder if messing with the active diff settings/thresholds would make a difference...

[Alpha1BC]

Diff may or may not be a factor? I'd assume it's setup to be fully "locked" when you get on the throttle but open if it gets into ABS/ESC so the brake system isn't having to fight the diff to control the car. If it's slow to open it could be an issue, but I'd think it's nearly instantaneous and opens as soon as the nannies kick in if I had to guess.

[cdrptrks]

The back end is squirrely for the first few miles in cooler temperatures (40s and 50s Fahrenheit) on the stock 220 treadwear Goodyear Supercar 3 tires if I go anywhere near full throttle even with traction control on. I can imagine a less grippy higher treadwear snow tire would be even worse for heavy acceleration even if it is labeled as "performance" but not sure on the oscillations.

If you have a safe flat wide open empty parking lot you could try holding the traction control button down for 10 seconds to fully disable it and do some back to back light acceleration testing at low/safe speeds to narrow down if it is the car's electronics causing the oscillation or possibly the physical properties of the tires. Disclaimer: I'm not responsible if you lose control with traction control off and don't try that with any other cars or objects nearby.

[Tubtub]

Originally Posted by cdrptrks

The back end is squirrely for the first few miles in cooler temperatures (40s and 50s Fahrenheit) on the stock 220 treadwear Goodyear Supercar 3 tires if I go anywhere near full throttle even with traction control on. I can imagine a less grippy higher treadwear snow tire would be even worse for heavy acceleration even if it is labeled as "performance" but not sure on the oscillations.

If you have a safe flat wide open empty parking lot you could try holding the traction control button down for 10 seconds to fully disable it and do some back to back light acceleration testing at low/safe speeds to narrow down if it is the car's electronics causing the oscillation or possibly the physical properties of the tires. Disclaimer: I'm not responsible if you lose control with traction control off and don't try that with any other cars or objects nearby.

The back tires only start trying to play tag with each other under full acceleration, and only if you flat foot it for more than a few seconds.

The other thing is that for the most part there's no nannies going off during the phenomenon (I would be able to tell because the lights) unless of course the swaying causes me to lose traction which only happens at the end of first gear if I'm laying on it. But not in 3rd gear when I notice the phenomenon the most.