Michelin PS4S - BMW Star Spec - 255/35/19

[ZM2]

Hey guys, I posted this in the M2 forum a couple weeks ago: https://f87.bimmerpost.com/forums/sh....php?t=1597644

My BMW & Michelin contacts are not divulging the goods. Anyone know specifically what’s different with this new BMW Star spec?

[G4BR13L]

BMW claims these tires were specially developed for the design of the rear and front axles of the F8x. To meet the “BMW standards” they need to be BMW approved. It just means that the rubber compound, tread pattern, dimensions, ... are approved by BMW for this car. There might be a slight impact in cornering, overall stability when not using the approved tires. Imho what makes a specific tyre BMW approved is car dependant, this theoretically means that a tyre approved for the M3/M4 is not necessarily a good tyre for the M2 even if the dimensions are the same.

Initially for the F8x it was the Michelin Pilot Super Sport:

255/40 ZR18 (front)
275/40 ZR18 (rear)

255/35 ZR19 (front)
275/35 ZR19 (rear)

For the GTS the Michelin Pilot Sport Cup 2:

265/35 ZR19 (front)
285/30 ZR20 (rear)

[ZM2]

Yup, understand all that.

Just wondered if any of the M3/4 crowd had gotten their hands on the new 255 BMW Star spec to note any visible differences in tread pattern/groves, or had driven them both back to back.

[G4BR13L]

The BMW approved are 255/35 R19 96Y XL. This means stronger sidewalls but the tyre was not manufactured exclusively for BMW, imho you are overthinking this.

[ZM2]

Not sure how asking the group for feedback is overthinking it.

Like many here I’ve run lots of different tire sizes and compounds F/R on both the street and track, and they all have pros/cons depending on the application & situation.

Getting another data point, especially since it’s a new offering in a tire that a lot of us use for the street, is a good thing for everyone.

Lastly, all the 255/35/19 PS4S’s are 96Y. Not sure which tire you’re comparing the new PS4S BMW Star Spec to.

[G4BR13L]

It is the only 255 with the * according to the Belgian website and also the only one with 96Y XL:

https://www.michelin.be/nl/banden/mi...ilot-sport-4-s

Which tyres are you comparing then to ask exactly what difference there is? Difference between which two tyres exactly?

[G4BR13L]

I also don’t understand what more you need to know then the fact these were designed for the design of the axles. Does it matter which polymer they used or how many channels? I did not know that this was some kind of fetish for some. If you feel the difference you must be a pro driver?

[ZM2]

We're not going to be able to figure anything out from spec sheets, as they all say something different:

https://www.michelin.be/nl/banden/mi...ilot-sport-4-s
https://www.tirerack.com/tires/Spec....Pilot+Sport+4S
https://www.michelinman.com/upload/m...t-sport-4s.pdf

Knowing this about spec sheets and tires is why I was asking if anyone had their hands on one of these, yet, vs getting the typical Star vs non-Star speech. I don't really care if it has a Star or not, I'm curious if there are any visible construction differences and any other intel we can get on the tire from reputable sources.

For instance, on the BE site it lists water performance for the * as a 'B'. On the TR and Michelin US sites, it lists the * as a lb heavier than the current 96Y 255 PS4S. Does this mean the rain groves are narrower b/c there's more flat tread for dry grip? I have no idea, but that's what I would prefer from a 255. We won't know until someone sees one of these tires.

Can some of us tell a difference? Absolutely! I drive endurance races with US BMW instructors and pro's that are in World Challenge, have 40+ track days in my personal M2, and have driven Spa and 2 full days on the Ring on your side of the world. I'm not the only guy here in that boat, and we can all pick up on these nuances. It's part of being in tune with your machine.

I really didn't expect to get trolled on my first post here. I know some of you actually drive your cars to the limit, so I'm guessing you can probably provide better input. If I end up being the first one to get one of these, then I'll provide the input.

[CanAutM3]

The 255/35R19(*) is the REAR tire option for the new G20 3-series 8.5" wide wheel. I would NOT recommend for using it on the front 9" wide F8X wheel.

[CanAutM3]

Originally Posted by ZM2

We're not going to be able to figure anything out from spec sheets, as they all say something different:

https://www.michelin.be/nl/banden/mi...ilot-sport-4-s
https://www.tirerack.com/tires/Spec....Pilot+Sport+4S
https://www.michelinman.com/upload/m...t-sport-4s.pdf

Knowing this about spec sheets and tires is why I was asking if anyone had their hands on one of these, yet, vs getting the typical Star vs non-Star speech. I don't really care if it has a Star or not, I'm curious if there are any visible construction differences and any other intel we can get on the tire from reputable sources.

For instance, on the BE site it lists water performance for the * as a 'B'. On the TR and Michelin US sites, it lists the * as a lb heavier than the current 96Y 255 PS4S. Does this mean the rain groves are narrower b/c there's more flat tread for dry grip? I have no idea, but that's what I would prefer from a 255. We won't know until someone sees one of these tires.

Can some of us tell a difference? Absolutely! I drive endurance races with US BMW instructors and pro's that are in World Challenge, have 40+ track days in my personal M2, and have driven Spa and 2 full days on the Ring on your side of the world. I'm not the only guy here in that boat, and we can all pick up on these nuances. It's part of being in tune with your machine.

I really didn't expect to get trolled on my first post here. I know some of you actually drive your cars to the limit, so I'm guessing you can probably provide better input. If I end up being the first one to get one of these, then I'll provide the input.

Indeed, not many people here really understand the subtelties and importance of tire design. I am far from an expert, but I have done a fair bit of research on the topic in the quest to find the optimal tires for my use, so I can share what I've learned.

A manufacturer spec tire, such as the BMW star spec, is designed and optimized for a very specific application. It does not mean it is a better overall tire or is better on any BMW. It means the specific chassis and tire have been developped in conjunction for optmal performance. As I posted above, the 255/35R19 star PS4S is designed to be used on the rear of the G20 and for a 8.5" wide wheel, it will therefore be suboptimal to use it mounted on the front of the F8X on 9" wide wheel. I'd say it it better to stick with the generic version of the 255/35R19 PS4S here, since they are designed for "generic" use.

I also think it is OK to use different spec tires as long as they fit the intended design. For instance, on my 2015 M4, I used the AMG GT-S front 265/35R19(M0) PSS tire, since it was specifically designed for a 9" wide front wheel on a front engined rear wheel drive car, a perfect fit for a 437M shod F8X.

[CanAutM3]

Originally Posted by G4BR13L

The BMW approved are 255/35 R19 96Y XL. This means stronger sidewalls but the tyre was not manufactured exclusively for BMW, imho you are overthinking this.

No, he's not .

[ZM2]

Originally Posted by CanAutM3

The 255/35R19(*) is the REAR tire option for the new G20 3-series 8.5" wide wheel. I would NOT recommend for using it on the front 9" wide F8X wheel.

Interesting and thanks! How did you figure that out?

[ZM2]

Originally Posted by CanAutM3

Indeed, not many people here really understand the subtelties and importance of tire design. I am far from an expert, but I have done a fair bit of research on the topic in the quest to find the optimal tires for my use, so I can share what I've learned.

A manufacturer spec tire, such as the BMW star spec, is designed and optimized for a very specific application. It does not mean it is a better overall tire or is better on any BMW. It means the specific chassis and tire have been developped in conjunction for optmal performance. As I posted above, the 255/35R19 star PS4S is designed to be used on the rear of the G20 and for a 8.5" wide wheel, it will therefore be suboptimal to use it mounted on the front of the F8X on 9" wide wheel. I'd say it it better to stick with the generic version of the 255/35R19 PS4S here, since they are designed for "generic" use.

I also think it is OK to use different spec tires as long as they fit the intended design. For instance, on my 2015 M4, I used the AMG GT-S front 265/35R19(M0) tire, since it was specifically designed for a 9" wide front wheel on a front engined rear wheel drive car, a perfect fit for a 437M shod F8X.

I had seen the M0 265 for the PSS, but I do not see anything similar for the 4S. I’ve been running the generic 265 4S on my front 437M for 2yrs and don’t care for the turn in bc it’s not designed for a 9” wheel. The grip is great, the turn in is just a bit slow.

I do like the 4S over the PSS, tho, so that’s why I was looking at dropping to a 255 for the front. The best we can do in the rear on the M2 is 285, unless we drop to 30-series, which I’m not too interested in doing for the street.

Thanks for your input!

[G4BR13L]

Originally Posted by CanAutM3

No, he's not .

Whether you like it or not, I don’t care but he is overthinking it and so are you! If it would really matter, cinsidering you are a pro driver and all, you would not be on these forums asking about Michelin tyres. All we should care about is that these star rated tyres have passed BMW testing. What the bloody difference is with a non star rated tyre is irrelevant and is imho only interesting to people with autistic tendencies, like a lot of people on these forum (take the hint).

First of all during vehicle development BMW runs a sh!tload of computer simulations. They come up with initial tyre specifications considering also axle elasticity, ... Then they test prototype tyres on a tyre map tester by applying lateral and longitudinal forces.

Then they test tyres on early models of the car and wear these tyres. These are then tested again in a lab and mounted again on test cars and driven on wet tracks and hydroplaning tests in bends.

They also do a 100 km/h to 0 km/h brake test in dry conditions.

They do a rim roll test with a tyre pressure around 1.2 psi (1.1 G of lateral acceleration).

BMW drives for example (i don’t know exactly how many) rounds on the Nurburgring with a specific tyre to test the structural strength. They record this driving data and in labs they test complete axles and wheels against this recorded data.

Then there is a tyre endurance test. They fit tyres on a preproduction car and again wear the tyres. The wear pattern should be the same on the four tyres. These worn tyres are then subjected to other tests (noise, hydroplaning, ...)
They also do a rolling resistance test. In the laboratory they check roll resistance on drum testers and conduct tests on the vehicle itself to verify fuel consumption.

They test the tyres for their handling properties (steering, ditectional stability, corner handling, ...). They also test legal compliance of the tyres (pass-by noise tests, ...). Tests around comfort (tyre dampening, roll noise, ...) are conducted and for ensuring quality they only focus on a couple of tyre manufacturers such as Michelin, Continental, ...

A tyre that meets all the BMW tyre specifications and passes all the aformentioned test are essential for the premium driving and comfort qualities This is why all BMW tire specifications (summer, winter and all-season tyres) are marked with the BMW tyre mark (*).

Did I get all the details 100% correct? Hell no, because run flats is a different story that I did not even touch. And because I am not autistic I don’t care about all the details. 99% of the people here don’t care about the theoretical engineering explanation of topics, they like to keep it pragmatic.

All I know is that specific tyres undergo rigourous testing and if BMW think that specific tyres deserve the * then this is all I need to know. Don’t forget that these kind of testing has been going on for over 15 years for all I know and it tyre providers such as Michelin know what BMW expects so it is perfectly possible that they release a specific tyre that meet the BMW requirements but because BMW still needs to conduct the tests they are not (yet) designated with the *. It is perfectly possible that a tyre gets the * without any freaking change done to the specific tyre.

So yes you are OVERTHINKING this! Up until 20 years ago I would have said yes you are right but looking at the big six tyre providers there aren’t nowadays really “bad” tyres.

[CanAutM3]

Originally Posted by G4BR13L

Whether you like it or not, I don’t care but he is overthinking it and so are you! If it would really matter, cinsidering you are a pro driver and all, you would not be on these forums asking about Michelin tyres. All we should care about is that these star rated tyres have passed BMW testing. What the bloody difference is with a non star rated tyre is irrelevant and is imho only interesting to people with autistic tendencies, like a lot of people on these forum (take the hint).

First of all during vehicle development BMW runs a sh!tload of computer simulations. They come up with initial tyre specifications considering also axle elasticity, ... Then they test prototype tyres on a tyre map tester by applying lateral and longitudinal forces.

Then they test tyres on early models of the car and wear these tyres. These are then tested again in a lab and mounted again on test cars and driven on wet tracks and hydroplaning tests in bends.

They also do a 100 km/h to 0 km/h brake test in dry conditions.

They do a rim roll test with a tyre pressure around 1.2 psi (1.1 G of lateral acceleration).

BMW drives for example (i don’t know exactly how many) rounds on the Nurburgring with a specific tyre to test the structural strength. They record this driving data and in labs they test complete axles and wheels against this recorded data.

Then there is a tyre endurance test. They fit tyres on a preproduction car and again wear the tyres. The wear pattern should be the same on the four tyres. These worn tyres are then subjected to other tests (noise, hydroplaning, ...)
They also do a rolling resistance test. In the laboratory they check roll resistance on drum testers and conduct tests on the vehicle itself to verify fuel consumption.

They test the tyres for their handling properties (steering, ditectional stability, corner handling, ...). They also test legal compliance of the tyres (pass-by noise tests, ...). Tests around comfort (tyre dampening, roll noise, ...) are conducted and for ensuring quality they only focus on a couple of tyre manufacturers such as Michelin, Continental, ...

A tyre that meets all the BMW tyre specifications and passes all the aformentioned test are essential for the premium driving and comfort qualities This is why all BMW tire specifications (summer, winter and all-season tyres) are marked with the BMW tyre mark (*).

Did I get all the details 100% correct? Hell no, because run flats is a different story that I did not even touch. And because I am not autistic I don’t care about all the details. 99% of the people here don’t care about the theoretical engineering explanation of topics, they like to keep it pragmatic.

All I know is that specific tyres undergo rigourous testing and if BMW think that specific tyres deserve the * then this is all I need to know. Don’t forget that these kind of testing has been going on for over 15 years for all I know and it tyre providers such as Michelin know what BMW expects so it is perfectly possible that they release a specific tyre that meet the BMW requirements but because BMW still needs to conduct the tests they are not (yet) designated with the *. It is perfectly possible that a tyre gets the * without any freaking change done to the specific tyre.

So yes you are OVERTHINKING this! Up until 20 years ago I would have said yes you are right but looking at the big six tyre providers there aren’t nowadays really “bad” tyres.

Skimming through this post, I wonder who is autistic

[CanAutM3]

Originally Posted by ZM2

I had seen the M0 265 for the PSS, but I do not see anything similar for the 4S. I’ve been running the generic 265 4S on my front 437M for 2yrs and don’t care for the turn in bc it’s not designed for a 9” wheel. The grip is great, the turn in is just a bit slow.

I do like the 4S over the PSS, tho, so that’s why I was looking at dropping to a 255 for the front. The best we can do in the rear on the M2 is 285, unless we drop to 30-series, which I’m not too interested in doing for the street.

Thanks for your input!

Yes, sorry I should have been more specific, the 265/35R19 I ran on my previous M4 were indeed PSS and not PS4S. I was just mentioning an example where it is possible to find alternate spec tires for a very good fit. I fixed my OP to make it clearer.

Tires specifically designed for the front axle are usually designed with a rounder contact patch to improve turn-in response and with better aquaplaning resistance to "cut" through water. Tires specifically designed for the rear axle usually have a squarer contact patch for improved straight line traction. Generic tires are somewhere in between but often closer to rear tire design.

Sadly, at this stage, there is no "optimal" PS4S fitment for the 19" F8X so one has to settle for the generic ones.

[G4BR13L]

Originally Posted by CanAutM3

Skimming through this post, I wonder who is autistic

You and I buddy.

[CanAutM3]

Originally Posted by G4BR13L

You and I buddy.

[ZM2]

Originally Posted by G4BR13L

Whether you like it or not, I don’t care but he is overthinking it and so are you! If it would really matter, cinsidering you are a pro driver and all, you would not be on these forums asking about Michelin tyres. All we should care about is that these star rated tyres have passed BMW testing. What the bloody difference is with a non star rated tyre is irrelevant and is imho only interesting to people with autistic tendencies, like a lot of people on these forum (take the hint).

First of all during vehicle development BMW runs a sh!tload of computer simulations. They come up with initial tyre specifications considering also axle elasticity, ... Then they test prototype tyres on a tyre map tester by applying lateral and longitudinal forces.

Then they test tyres on early models of the car and wear these tyres. These are then tested again in a lab and mounted again on test cars and driven on wet tracks and hydroplaning tests in bends.

They also do a 100 km/h to 0 km/h brake test in dry conditions.

They do a rim roll test with a tyre pressure around 1.2 psi (1.1 G of lateral acceleration).

BMW drives for example (i don’t know exactly how many) rounds on the Nurburgring with a specific tyre to test the structural strength. They record this driving data and in labs they test complete axles and wheels against this recorded data.

Then there is a tyre endurance test. They fit tyres on a preproduction car and again wear the tyres. The wear pattern should be the same on the four tyres. These worn tyres are then subjected to other tests (noise, hydroplaning, ...)
They also do a rolling resistance test. In the laboratory they check roll resistance on drum testers and conduct tests on the vehicle itself to verify fuel consumption.

They test the tyres for their handling properties (steering, ditectional stability, corner handling, ...). They also test legal compliance of the tyres (pass-by noise tests, ...). Tests around comfort (tyre dampening, roll noise, ...) are conducted and for ensuring quality they only focus on a couple of tyre manufacturers such as Michelin, Continental, ...

A tyre that meets all the BMW tyre specifications and passes all the aformentioned test are essential for the premium driving and comfort qualities This is why all BMW tire specifications (summer, winter and all-season tyres) are marked with the BMW tyre mark (*).

Did I get all the details 100% correct? Hell no, because run flats is a different story that I did not even touch. And because I am not autistic I don’t care about all the details. 99% of the people here don’t care about the theoretical engineering explanation of topics, they like to keep it pragmatic.

All I know is that specific tyres undergo rigourous testing and if BMW think that specific tyres deserve the * then this is all I need to know. Don’t forget that these kind of testing has been going on for over 15 years for all I know and it tyre providers such as Michelin know what BMW expects so it is perfectly possible that they release a specific tyre that meet the BMW requirements but because BMW still needs to conduct the tests they are not (yet) designated with the *. It is perfectly possible that a tyre gets the * without any freaking change done to the specific tyre.

So yes you are OVERTHINKING this! Up until 20 years ago I would have said yes you are right but looking at the big six tyre providers there aren’t nowadays really “bad” tyres.

Wow, that’s a lot of spew with no coherent help. CanAutM3 already answered the question with real world input.

[AlpsRider]

Some people are more sensitive to handling and more analytical than others. Personally I can feel the difference in the way my car handles when I change the cold tire inflation pressure by even just one pound. It makes a difference on bumps, turn in, and break away behavior. Some people can't tell the difference between Starbucks and Denny's coffee either

[irokwrx]

Originally Posted by G4BR13L

The BMW approved are 255/35 R19 96Y XL. This means stronger sidewalls but the tyre was not manufactured exclusively for BMW, imho you are overthinking this.

Over thinking it.....LOL

Check out this vid.

[ONEof500]

Originally Posted by irokwrx

Over thinking it.....LOL

Check out this vid.

Ha! I was just about to post this video. Well done.