[dmicah]

Originally Posted by 335dFan

I would have agreed with you until a few weeks ago when I became the outlier. I have the space saver spare. I changed out my OEM runflats to Michelin Pilot Sport All Season 4s, and then picked up a screw in my right rear within about 150 miles. I was screwed.

Arr arr arr very funny fellow dad-joker! I'm sorry my magical axiom failed for you. I hope you popped on the spare and got the tire to a shop for a quick patch and all is well again.

[doug_999]

Originally Posted by 335dFan

Interesting factoid which surprises me a bit. I ordered my 2021 M40i in late 2020 and picked it up on 14 Jan 2021...with 19" wheels and M Sport Differential (and Adaptive M Suspension).

I have now located the place in the manual to which you refer. I wish I had read that before buying my Michelin Pilot Sport All Season 4 tires a few weeks ago. Now that might explain a strange sensation I have been feeling when taking a corner and then stomping on the go-pedal. A couple of times I did that and could feel the slight squirrely feeling in the steering wheel. I wonder why that is? Strange phenomenon. Now to figure out what to do about it.

Right - my bad, it says
"If the vehicle is equipped with an M Sport differential and all-weather tires on 19 inch rims, this can alter handling, for instance the vehicle
may skid. There may be a risk of accident or risk of damage to property. If the vehicle is equipped with an M Sport differential, do not mount all-weather tires on 19 inch rims."

The configurator shows a change from 887M to 887 wheels. So are the 887M non-staggered and the 887 staggered?

[335dFan]

Originally Posted by dmicah

Arr arr arr very funny fellow dad-joker! I'm sorry my magical axiom failed for you. I hope you popped on the spare and got the tire to a shop for a quick patch and all is well again.

It gets better, then worse. The tire guys patched it for free and it was a slow leak so I just drove to the place. But then some other forum member here who has better attention to detail than I do pointed out a little warning on page 295 of the 2021 manual. With M-Sport Differential, no all seasons with 19" wheels. So now I'm bummed again. it's more than a warning to me as I have noticed some subtle indications of what the warning talks about.

[335dFan]

Originally Posted by doug_999

The configurator shows a change from 887M to 887 wheels. So are the 887M non-staggered and the 887 staggered?

My 2021 OEM 19" wheels are M Style 698M. I run a square setup as I don't care for staggered from a total life cycle perspective (i.e., rotation, etc.).

But now I have a real dilemma. I may want to unload my new Michelin Pilot Sport All Season 4 tires that I just paid $1,000 for. But what to replace them with? I am a lifelong Michelin fan who has never bought all season tires before now, and I live in California so I don't really need anything but all seasons. It seems the Michelin Performance Summer tires (Pilot Sport 4 SUV) are low in inventory now. I wouldn't mind having summers and winters again like before even though I don't need them. But now I have to unload the brand new all seasons.

I was planning to buy some 18" wheels as my second set and then put Falken Wildpeak All Terrain Trails on them. But now I'm afraid those are considered all seasons as well. Very confusing.

[dmicah]

Originally Posted by 335dFan

It gets better, then worse. The tire guys patched it for free and it was a slow leak so I just drove to the place. But then some other forum member here who has better attention to detail than I do pointed out a little warning on page 295 of the 2021 manual. With M-Sport Differential, no all seasons with 19" wheels. So now I'm bummed again. it's more than a warning to me as I have noticed some subtle indications of what the warning talks about.

I mean, maybe this would be less controversial as a PM, but I find it hard to believe that the M-sport differential would be a problem with 19" all seasons. I've got it with 20" all seasons. They might just be worried that it's a bit more tail happy with the grip of the all seasons. The whole thing sounds kinda hinky to me...

Actually, I just looked at the manual for my 2020 and same warning does appear. HOWEVER: it appears as a safety warning under the section for winter tires. So what I think they're saying is that in winter conditions with the differential all seasons are more slippery than winter tires. Which we knew. So maybe don't use the 19" all seasons to drive over to Tahoe

[335dFan]

Originally Posted by dmicah

I mean, maybe this would be less controversial as a PM, but I find it hard to believe that the M-sport differential would be a problem with 19" all seasons. I've got it with 20" all seasons. They might just be worried that it's a bit more tail happy with the grip of the all seasons. The whole thing sounds kinda hinky to me...

Actually, I just looked at the manual for my 2020 and same warning does appear. HOWEVER: it appears as a safety warning under the section for winter tires. So what I think they're saying is that in winter conditions with the differential all seasons are more slippery than winter tires. Which we knew. So maybe don't use the 19" all seasons to drive over to Tahoe

Yeah, well I'm now an old fart so I wasn't planning to use them in real snow anyway, but rather bought them just for those situations where the temperature gets down in the low 40s and below. I live up in NorCal where it actually does that once in a while. And I don't probably have any interest any more about taking it to the track where that phenomenon would be mostly felt. But when alone I do tend the push the car to my limits (not its limits) and it definitely felt more "over-steerish" when I romped on it after taking a diagonal turn to the left and had it mostly straightened out. It was more like the M Sport Differential was working to keep things right but couldn't make up its mind perfectly well. It didn't concern me as much as it surprised me. I'm one of those guys who feels and hears everything in my car that is just slightly unusual.

But I still want a second set. More for mild off-road than winter, but pulling double duty if needed. Like Falken Wildpeak A/T Trail. They are M+S tires but not true winters. And a very off-roady tread.

[doug_999]

Something does not make sense. While I'm not a tire/suspension/bmw engineer..... I do have a degree in Mechanical Engineering.

I could totally understand if BMW was like
"Don't use a square set with the M-Sport Diff". That would make total sense.
But to come and say "don't use it with 19" all-seasons", that just doesn't make sense. How would "19 inch summer" tires have anything to do with the differential?

Anyone?

[335dFan]

Originally Posted by doug_999

Something does not make sense. While I'm not a tire/suspension/bmw engineer..... I do have a degree in Mechanical Engineering.

I could totally understand if BMW was like
"Don't use a square set with the M-Sport Diff". That would make total sense.
But to come and say "don't use it with 19" all-seasons", that just doesn't make sense. How would "19 inch summer" tires have anything to do with the differential?

Anyone?

OK, let me offer my thoughts. I'm not even an engineer, but I do tend to think like one...whatever. These thoughts are based on reading, observations, discussions with track instructors, and just generally paying attention for the last 50+ years. And not just pulling this out of my rectal databank.

Assertions:
1. Understeer is safer for your average driver than oversteer.
2. BMW tends to tune their mainstream vehicles (notwithstanding their Ultimate Driving Machine moniker) for the average driver, and thus tends to dial in more understeer.
3. I believe that the staggered setups are generally more understeery than the square setups, but I could be all wrong. Plus staggered is much "cooler" looking for the average owner.
4. An old track instructor once told me that square setups were more neutral in general (meaning between the under and over extremes). Same thing with having equal PSI on all four corners.
5. With all that in mind, I would imagine that BMW engineers have tried to find the sweet (safe) spot for their various wheel/tire configuration and have tuned their hardware and firmware to that end. Also, I expect they have been aware that certain configurations somewhat at the extremes of their likely average driver configurations will mess with their design goals.
6. M Sport Differential I guess probably pushes the envelope a bit with their design goals, and also further does so with certain wheel size and tire makeup combinations. Hence, it makes it less "safe" for the average driver.
So, the lawyers and tech writers felt it wise to insert the warning.

End of Assertions

From driving the very configuration that they are warning against, I can kinda/sorta understand why they decided to put that warning in.

Now, being 77 years old, I am just trying to decide whether I care or not, and whether I can just adjust my muscle memory reactions for this enlightened understanding.

On the other hand, maybe I'll just go to Michelin Pilot Sport 4 SUV, if I can find them.

[doug_999]

good points 335dFan !

[GS - X3]

Perhaps BMW is specifically referring to the relatively new designation of "All Weather" tires vs. the more traditional "All Season". All Weather tires differ from All Season tires in that they qualify for the "Snowflake" designation on the sidewall, making them a true "Snow Tire" that also offers All Season capabilities, and a longer tread life than traditional "Winter" tires.

[335dFan]

Originally Posted by GS - X3

Perhaps BMW is specifically referring to the relatively new designation of "All Weather" tires vs. the more traditional "All Season". All Weather tires differ from All Season tires in that they qualify for the "Snowflake" designation on the sidewall, making them a true "Snow Tire" that also offers All Season capabilities, and a longer tread life than traditional "Winter" tires.

You may be onto something here. Here is the warning in my 2021 manual from page 295.

"If the vehicle is equipped with an M Sport differential
and all-weather tires on 19 inch rims,
this can alter handling, for instance the vehicle
may swerve off course. There may be a risk of
accident or risk of damage to property. If the
vehicle is equipped with an M Sport differential,
do not fit all-weather tires on 19 inch rims."

The term "all-weather" is specifically used. From a superficial search on the internet (why didn't I know this already?) the following distinction is presented: "All-weather tires are distinguished by the unique 3-peak mountain snowflake pictogram on the sidewalls which indicates that the tire has at least 110% the traction of a standard all-season tire (for the curious, the standard used is ASTM E1136-14)." My Michelin Pilot Sport All Season 4s do not have that 3-peak symbol, but I already knew that. What I was doing was conflating the two terms "all season" and "all weather," and it appears that is not accurate.

This does not make my driving impression reported earlier go away, but it seems to indicate the manual warning does not necessarily apply to all season tires, but only to all weather tires.

This does mess with my follow-on plans to get Falken Wildpeak A/T tires, because they are definitely all-weather tires. But maybe I'm home free because I was going to mount them on 18" rims. I'll take a guess that if the warning applies to 19" rims, it would be more so with 18". I wonder.

This seems to be a problem for those of us with M Sport Differential, with what I believe is a common practice: going to a smaller wheel and a "higher" aspect ratio tire for winter and all-terrain use. It would seem to mean that to make the car handling "safe," I would have to go with a 20" wheel, which is exactly the opposite from the common practice.

[Negtvions]

Originally Posted by dmicah

Yeah, I think we're confusing two different axes in this discussion:

• RFT vs. not RFT
• Summer vs. All Season

WRT RFT vs regular tires, I'm a strong advocate for ditching RFTs and toting a spare or some mobility kit solution. My experience is that if you have a spare, that magically prevents you from ever needing it.

I agree with your statements above re: how to approach the issue of summer vs all season (in most cases). It's better to have two sets of wheels, one for summer and one for winter. I'm not doing that anymore because I just don't want to consume garage space in my current situation. And for me, the A/S 4's are the right solution out here in the desert where my family might occasionally end up up in big bear. They're great tires (and the OEM tires for the C8 corvette, I might add (unless you get the Z51 package)). I have the PS4S on my sedan and wow, it's an amazing handling tire! Agree with your assessment about grip and comfort.

I'm out in San Diego and and considering these tires precisely for trips to Big Bear in the winter. Have you driven on the Michelin all seasons in that kind of environment yet?
Thoughts?

[doug_999]

Unfortunately, the configurator takes away your "All Season" tires and replaces them with Summer when you add the M-Sport. So I think they mean "All Season".

[335dFan]

Originally Posted by doug_999

Unfortunately, the configurator takes away your "All Season" tires and replaces them with Summer when you add the M-Sport. So I think they mean "All Season".

Not sure what MY that configurator is for, but I suspect it might have something to do more with speed rating of the tires.

[doug_999]

Originally Posted by 335dFan

Not sure what MY that configurator is for, but I suspect it might have something to do more with speed rating of the tires.

Just for a differential swap?

[335dFan]

Originally Posted by doug_999

Just for a differential swap?

Yeah, that doesn't make sense does it? I think I am going to write a letter to BMW NA and see if they will try to give me something other than a marketing or business answer. I want to find out more about that warning and what my options are for Winter/AT tires are at this point, and whether they really meant all season or all weather. I don't anticipate a useful response, but what the hey. In the meantime I am going to keep my all seasons on, but hold off on the Falken Wildpeaks.

[dmicah]

Originally Posted by Negtvions

I'm out in San Diego and and considering these tires precisely for trips to Big Bear in the winter. Have you driven on the Michelin all seasons in that kind of environment yet?
Thoughts?

I will never forget the phone call I got from my daughter when she was driving the M40i back from Fort Irwin in the winter. Google maps had directed her to avoid traffic by going over one of the foothills of Big Bear in the middle of a sudden snowfall. She called me in mid-slide backwards down the hill. She got it under control but was suitably freaked. I made her backtrack and deal with the traffic, which she was happy to do. At this time the car was shod with the Michelin AS3+

My sense has been that the Michelins are slightly less capable in light snow than the Conti DWS06+'s. This was more the case, I believe with the AS3+'s than the AS4's. I've shown the comparison of user reviews below between the two tires from Tirerack and it seems to sort of support the point (DWS on the left, AS4 on the right).

I love the AS4s and the AS3's were probably 80% through their tread when my daughter called me, but if you anticipate going to Big Bear regularly buy a set of snows. Or maybe consider the DWS06+'s--they're both great tires.

[glennbk]

They are, but you sacrifice on-center feel with the Continentals. Sidewalls are also softer than the Michelin's. Compared to the OE tires, anything is better. I'm not a fan of run flats. I feel like you sacrifice a lot for what you get in return.

[doug_999]

Had the DWS 06 on my 650GC. Mushy ride and in the snow, somewhat scary. Maybe the 06+ is better ?

[gphin]

I know there are many Conti and Michelin lovers here and I've probably used 40-50 sets of tires over the years, including Mich and Conti. Recently replaced my oem Alenza runflats with 20" staggered 275/245 Sumitomo HTR A/S PO3 all seasons. Look good and very satisfied with handling, quiet ride, and wear so far. And at the time, got a great price. Good ratings on Tire Rack and elsewhere. I'd throw in the mix for those looking to replace with all seasons.

[glennbk]

I think the main reason you see so many Continental and Michelin tire is because they generate the most profit and are always in stock. Do either make a perfect tire? No. Do I prefer Michelin? Yes. They've never failed me except for the Snowpocalypse 2021. We had 2" of ice everywhere. Had absolutely no traction. Lesson learned. And now, I'm finding out that Alenza's are coming with my car. Not happy...

[jeffvb9]

255/40/21 instead of 265/40/21?

I see a lot of people going to this:

FR 265/40/21
RR 295/35/21

I see on here most are going to 255 on the front. Any specific reason?