[Fastfwd]

Does anyone know what the minimum temperature is for these tires to just be on the car supporting the vehicle's weight in below freezing temperatures? They're supposed to be more Pilot Sport Cup 2 than the normal PS4S tires. So, even less cold weather tolerant?

I thought I might limp through winter months just leaving them mounted on the stock rims until spring (just not driving on them), but I've seen somewhere that at 20f (-7c?) PS4s tires shouldn't even be supporting weight. They can crack, etc.

I don't want to take that chance if that's current information.

[turo]

Is be curious as well. I read in a Porsche forum that PS4Ss (non-star) start getting a bit dicey below 40 degrees F. I just went ahead and slapped some PSS all-seasons on my car since we get a lot of sub-freezing temps here but not much snow.

[Squidget]

I know of the 40F/20F rule as coming from a GM bulletin:

https://static.nhtsa.gov/odi/tsbs/20...82862-5448.pdf

Edit: here's a quote from the bulletin:

"Advise customers of these vehicles that they are equipped with a high performance
summer-only tire that will have reduced traction performance at temperatures below
approximately 40°F (5°C). GM recommends installing winter tires if driving below these
temperatures. Avoid driving, moving, or test-driving vehicles equipped with high
performance summer-only tires below 20°F (−7°C), as operating at these temperatures
can cause damage to the tires."

*You can drive summers (carefully!) in 20F weather, as long as the tires themselves are above 20F. That means they are warm first (aka garage) and you don't give them a chance to cool down (aka parking outside).

Edit: Fixed my incorrect units, my bad.

[///M TOWN]

40°

[Ruebarb]

Avg Hi temp of 40 is the general rule, the rubber becomes a hockey puck in the winter

[Fastfwd]

Originally Posted by Ruebarb

Avg Hi temp of 40 is the general rule, the rubber becomes a hockey puck in the winter

40f for driving, right? What about just sitting in the driveway if the temps are below freezing? Down to 20f degrees or less?

[fangelov]

Originally Posted by Squidget

I know of the 20C rule as coming from a GM bulletin:

https://static.nhtsa.gov/odi/tsbs/20...82862-5448.pdf

Unless there's conflicting documentation, it's probably reasonable to say that it's a bad idea to run summers below 20C* except in emergencies.

*You can drive summers (carefully!) in 20C weather, as long as the tires themselves are above 20C. That means they are warm first (aka garage) and you don't give them a chance to cool down (aka parking outside).

20C(Celsius) or 20F (Fahrneheit)?

[Squidget]

Originally Posted by fangelov

20C(Celsius) or 20F (Fahrneheit)?

Edit. Agh, I swapped units, didn't I?

Here's the quote:

"Advise customers of these vehicles that they are equipped with a high performance
summer-only tire that will have reduced traction performance at temperatures below
approximately 40°F (5°C). GM recommends installing winter tires if driving below these
temperatures. Avoid driving, moving, or test-driving vehicles equipped with high
performance summer-only tires below 20°F (−7°C), as operating at these temperatures
can cause damage to the tires."

[Fastfwd]

Originally Posted by Squidget

Edit. Agh, I swapped units, didn't I?

Here's the quote:

"Advise customers of these vehicles that they are equipped with a high performance
summer-only tire that will have reduced traction performance at temperatures below
approximately 40°F (5°C). GM recommends installing winter tires if driving below these
temperatures. Avoid driving, moving, or test-driving vehicles equipped with high
performance summer-only tires below 20°F (−7°C), as operating at these temperatures
can cause damage to the tires."

I've seen a similar bulletin type quote that cites that if they are subjected to temperatures below 20f that they should be warmed up slowly before being mounted, driven on, and/or supporting weight in paraphrase.

The supporting weight is what concerns me. I thought I might limp through winter not driving on them and they would be ok. Now, I'm sort of in a position to hastily decide on a set of actual all seasons and finding somewhere I can trust to swap these out.

The manual only cites not driving on them. Hell, Discount Tire lists PS4S as an 'All Season' tire. So, I'm not sure what to believe.

[akumachu]

When I did my research, this was on the TireRack's Michelin PS4S page.
```
Note: Tires exposed to temperatures of 20 degrees F (-7 degrees C) or lower must be permitted to gradually return to temperatures of at least 40 degrees F (5 degrees C) for at least 24 hours before they are flexed in any manner, such as by adjusting inflation pressures, mounting them on wheels or using them to support, roll or drive a vehicle.

Flexing of the specialized rubber compounds used in Max Performance Summer tires during cold-weather use can result in irreversible compound cracking. Compound cracking is not a warrantable condition because it occurs as the result of improper use or storage, tires exhibiting compound cracking must be replaced.


```

So yeah, I swapped to my winter wheels quite quickly once it turned cold.

[Fastfwd]

Originally Posted by akumachu

When I did my research, this was on the Michelin PS4S page.
```
Note: Tires exposed to temperatures of 20 degrees F (-7 degrees C) or lower must be permitted to gradually return to temperatures of at least 40 degrees F (5 degrees C) for at least 24 hours before they are flexed in any manner, such as by adjusting inflation pressures, mounting them on wheels or using them to support, roll or drive a vehicle.

Flexing of the specialized rubber compounds used in Max Performance Summer tires during cold-weather use can result in irreversible compound cracking. Compound cracking is not a warrantable condition because it occurs as the result of improper use or storage, tires exhibiting compound cracking must be replaced.


```

So yeah, I swapped to my winter wheels quite quickly once it turned cold.

That's what I saw somewhere too. So, I guess there is no avoiding putting actual all seasons on the car. No star compound PS4s until I decide on wheels next spring.

Thanks.

[Squidget]

FWIW, you'll find other drivers who claim to drive summers in cold weather all the time and never have any problems with cracking. That, in effect, the whole winter thing is a sham to sell more tires. But ya know, internet.

Until I see a reputable source to contradict the official recommendations, I'd rather not risk it. I guess Big Tire wins again (lol).

[Fastfwd]

I squeaked an order in this week with Discount Tire for a set of PS4 All Seasons while they still had a $100 off offer. So, that's a relief from fearing what might happen to those precious star compound PS4s summer only tires. I may not get another set of the star compounds in the future. It would be a shame to not at least experience them to see how they compare to the regular PS4s when time comes to replace them.

[M2siast]

Originally Posted by Fastfwd

I squeaked an order in this week with Discount Tire for a set of PS4 All Seasons while they still had a $100 off offer. So, that's a relief from fearing what might happen to those precious star compound PS4s summer only tires. I may not get another set of the star compounds in the future. It would be a shame to not at least experience them to see how they compare to the regular PS4s when time comes to replace them.

Sorry, why is it important to compare a PS4S tire to a PS4? Star spec or not? I am not sure I get the symbolism.

[Fastfwd]

Originally Posted by M2siast

Sorry, why is it important to compare a PS4S tire to a PS4? Star spec or not? I am not sure I get the symbolism.

My understanding is that the 'Star' Compound version of the PS4s that comes on the G87 is a compound recipe developed by Michelin with BMW specifically for the G87. It supposedly has much of the 'Cup 2' DNA in it, etc.

Your 'off the shelf' PS4S tires from a tire dealer in the same size won't be as sticky, but perhaps better treadlife? I'm not certain myself. I haven't compared the tread-life ratings.

I haven't priced the star compound tires, but my guess is that they are just too pricey for me to replace them once worn with another set of star compound. I'll just run the off the shelf versions for my needs. I won't be tracking the car anyway.

My point was that I don't want to ruin the special compound tires before I have a chance to experience them. I may not buy another set unless I just can't believe the difference they make.

[M2siast]

Originally Posted by Fastfwd

My understanding is that the 'Star' Compound version of the PS4s that comes on the G87 is a compound recipe developed by Michelin with BMW specifically for the G87. It supposedly has much of the 'Cup 2' DNA in it, etc.

Your 'off the shelf' PS4S tires from a tire dealer in the same size won't be as sticky, but perhaps better treadlife? I'm not certain myself. I haven't compared the tread-life ratings.

I haven't priced the star compound tires, but my guess is that they are just too pricey for me to replace them once worn with another set of star compound. I'll just run the off the shelf versions for my needs. I won't be tracking the car anyway.

My point was that I don't want to ruin the special compound tires before I have a chance to experience them. I may not buy another set unless I just can't believe the difference they make.

I get it, but you didn’t buy PS4S tires, correct? You bought PS4.
If you want to compare PS4S* to off the shelf PS4S, you’d have to buy the PS4S tires too.
PS4 will be totally different.

Unless I’m misunderstanding.

[Fastfwd]

Originally Posted by M2siast

I get it, but you didn’t buy PS4S tires, correct? You bought PS4.
If you want to compare PS4S* to off the shelf PS4S, you’d have to buy the PS4S tires too.
PS4 will be totally different.

Unless I’m misunderstanding.

I bought PS4 'All Seasons' to put on the stock wheels. So, if that's what you are calling PS4 - then yes.

I am preserving my stock tires the PS4 'S' summer only tires for next year after winter. They will be mounted to an aftermarket set of wheels.

So, I'm running a winter set and a summer set. Does that make sense?

Once the stock star compound do wear out I probably won't replace them with star compound tires. THEN I will have something to compare the different blend of PS4 'S' compounds.

I'm talking about what will probably be a few years down the road. I think even the star compound are probably 30k mile tires, but not sure.

[M2siast]

Originally Posted by Fastfwd

I bought PS4 'All Seasons' to put on the stock wheels. So, if that's what you are calling PS4 - then yes.

I am preserving my stock tires the PS4 'S' summer only tires for next year after winter. They will be mounted to an aftermarket set of wheels.

So, I'm running a winter set and a summer set. Does that make sense?

Once the stock star compound do wear out I probably won't replace them with star compound tires. THEN I will have something to compare the different blend of PS4 'S' compounds.

I'm talking about what will probably be a few years down the road. I think even the star compound are probably 30k mile tires, but not sure.

I got it now. You will not replace them with star marked tires. That's probably a good idea.
I am doing the same, I think the non-star tires are better (I said this before and was flamed here, so I will just say it again and expect the same). So no star spec Michelins for me.

I wrote to Tyre Reviews asking him to compare the Pirelli and Michelin star marked tires if he has a chance. That chance might not come. Hard for us to compare them ourselves too, especially because when you replace tires the old ones were old anyway, so new tires always feel better.

[rons e92]

I'll be honest, I didn't know any of this last year as I'm driving my G42 M240i through the NY winter on the PS4S star tires the ZTK package came with and I didn't have any issues.

Although I did have a blowout when I hit a pothole one day, I think it was in February, which makes sense now.

As of right now I'm sending it. It's gotten as cold as 28, although the coldest it's been when I've driven the car was 34 degrees. After cruising a bit it doesn't take much to get then up to 55-60 degrees. Not optimal, but they won't crack.

You do have to be careful. When I leave my office at the end of the day I need traffic to be totally clear to pull out onto the highway because if you give it too much throttle it immediately spins and wheel hops, then it kills power and I'd be a sitting duck. Honestly that wasn't an issue with the xDrive M240i.

I guess I'll be the guinea pig. If I have any other issues I'll update you guys.

I'm changing the rears for NT555RIIs in the spring anyway, so even if these tires aren't destroyed by the winter I'll destroy them with burnouts and donuts come spring.