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[SilverSlug]

When ordering Michelin Pilot 4S tires from Tire Rack, the sizes I want have different spec options…

FRONT:

255/35ZR19 92Y - ——————- $284 (23lbs)
255/35ZR19 96Y - ——————- $252 (24lbs)
255/35R19 96Y - Star BMW - $269 (25lbs)
(missing "Z")


REAR:

275/35ZR19 96Y - —————— $326 (25lbs)
275/35ZR19 100Y - —————— $319 (27lbs)
275/35ZR19 100Y - Star BMW - $341 (26lbs)



Can anyone please tell me:

• Why do the Star BMW tires have different load ratings?

• Is it okay to mismatch? (Front 96Y, Rear 100Y)

• Why are the Star BMW fronts the heaviest, but the Star BMW for the rears are lighter?

• Why do the front Star BMW tires missing the "Z" speed rating?

• Which ones are you guys running??

[TX]

Originally Posted by SilverSlug

When ordering Michelin Pilot 4S tires from Tire Rack, the sizes I want have different spec options…

FRONT:

255/35ZR19 92Y - ——————- $284 (23lbs)
255/35ZR19 96Y - ——————- $252 (24lbs)
255/35R19 96Y - Star BMW - $269 (25lbs)
(missing "Z")


REAR:

275/35ZR19 96Y - —————— $326 (25lbs)
275/35ZR19 100Y - —————— $319 (27lbs)
275/35ZR19 100Y - Star BMW - $341 (26lbs)



Can anyone please tell me:

• Why do the Star BMW tires have different load ratings?

• Is it okay to mismatch? (Front 96Y, Rear 100Y)

• Why are the Star BMW fronts the heaviest, but the Star BMW for the rears are lighter?

• Why do the front Star BMW tires missing the "Z" speed rating?

• Which ones are you guys running??

I can't answer all of this, but here goes...

The * tires are actually a special run of a tire per the manufacturers requests. Apparently they don't just slap a logo on a stock tire. This results in a different tire. How different? not really sure...or does it make a difference in the end?

A 35R(ZR) are the same tire. the load rating is 92,96 or 100 as above. The actual speed rating is the same - "Y" across the tires @ 186mph.

The R is actually for radial construction and ZR is tossed in for tires over 149MPH, which would be valid on a R tire with a Y speed rating as in your example.

edit: yes you can mix load ratings front and rear, but I would not mix a * and non star on the same end of the car.

[Drv4fun]

Originally Posted by SilverSlug

When ordering Michelin Pilot 4S tires from Tire Rack, the sizes I want have different spec options…

FRONT:

255/35ZR19 92Y - ——————- $284 (23lbs)
255/35ZR19 96Y - ——————- $252 (24lbs)
255/35R19 96Y - Star BMW - $269 (25lbs)
(missing "Z")


REAR:

275/35ZR19 96Y - —————— $326 (25lbs)
275/35ZR19 100Y - —————— $319 (27lbs)
275/35ZR19 100Y - Star BMW - $341 (26lbs)



Can anyone please tell me:

• Why do the Star BMW tires have different load ratings?

• Is it okay to mismatch? (Front 96Y, Rear 100Y)

• Why are the Star BMW fronts the heaviest, but the Star BMW for the rears are lighter?

• Why do the front Star BMW tires missing the "Z" speed rating?

• Which ones are you guys running??

I would like to add:
Keep in mind a star tire seems more specific for a model. For instance for the e92 the star was a 245/35-19 and 265/35-19. Those tires were made by Michelin (PS2), Continental and Pirelli (Pzero). They all had load ratings of 92f and 98r. You may find a newer tire with the star say a MSS in the same size but the load rating higher. That tire wasn’t designed for the E9x platform. Also some of the BMW tires have a 30 profile difference front to rear or 19/20 or 20/21 sizes. So I suspect that the tires you found aren’t a match for your size search.
Don’t rely too much on the search results regarding the star as the search is just pairing the stars together (tires for different cars f/r matched on a search)

From my experience if the tire wasn’t on a car out of the factory for your car, that tire probably wasn’t to design spec of that car but can be a star for a different car.
Of course I may be wrong but this is my understanding.
Also for Michelin please keep in mind that a ZP is a run flat and some sites just list it as a Z.

I have the 255/35-19 and 275/35-19 MSS star tires myself (sku for F80 M3).

That rear tire you found is actually the front tire for the new M3. You can see it yourself if you search for the new M3 on tirerack.
That front tire seems to be the rear tire for the new 330.
Of course there is most likely some overlap of star tire to different cars, but if tire category has to match the car ie a 220 non sport won’t have a star spec in a MPS4 or a MSC2.

All that said try to match the original load rating as best as you can or better but not too much higher (higher load rating might be stiffer and louder compared to the same tire in a lower rating).

[SilverSlug]

Wow interesting thank you both for the insights.

So then would the two Star tires I posted above work for the E9X M3?

Or would the 92Y be better for the front? And the 96Y better for the year? (These two indeed are lighter too).

[TX]

I just took a hike out to the garage. I have M. PSS 97Y on the front and PSS 101Y on the rear. (yes the old style sorry) They've been fantastic tires and have never had any issue of any kind except they melt away on the road too quickly -- oh and they pick up every single nail and screw on the road like glue.

I would think you would be just fine with the 96 and 100 combo.
If you really are after a few pounds you could go for the 92 and 96. If you're really going to push the car hopefully someone can chime in on how the ride will be different with the softer sidewall. Best of luck man,
Cheers.
X

[Drv4fun]

Originally Posted by SilverSlug

Wow interesting thank you both for the insights.

So then would the two Star tires I posted above work for the E9X M3?

Or would the 92Y be better for the front? And the 96Y better for the year? (These two indeed are lighter too).

I would say since the star spec aren’t tires for the car so I would think its no different than getting the non star (assuming bmw has specifics for each model not just the bmw brand). Tire shops recommended manufacture load rating or higher as marked on sticker on door sill of drivers door.
If you really want star tires in 255/275 I would say your best bet is the MSS, I have the sku numbers somewhere but I did a search on tirerack and they no longer show it, they have some other star pair (f/r higher load rating).

[SilverSlug]

So OEM load index for stock M3 tires are 97Y and 101Y… Meaning technically PS4 tires aren't even an option to run on a E9X M3??

I guess I have run MPSS?

[Ervin87]

Any of those will be fine.

[SilverSlug]

Even the 92Y and 96Y?

[Ervin87]

Originally Posted by SilverSlug

Even the 92Y and 96Y?

Yes. The factory 18" OE PSS is 93Y front and 97Y rear. I would go with the PS4S over the PSS anyway and you end up with 96Y all around.

[DrFerry]

Originally Posted by SilverSlug

When ordering Michelin Pilot 4S tires from Tire Rack, the sizes I want have different spec options…

FRONT:
255/35ZR19 92Y - ——————- $284 (23lbs)
255/35ZR19 96Y - ——————- $252 (24lbs)
255/35R19 96Y - Star BMW - $269 (25lbs)
(missing "Z")

REAR:
275/35ZR19 96Y - —————— $326 (25lbs)
275/35ZR19 100Y - —————— $319 (27lbs)
275/35ZR19 100Y - Star BMW - $341 (26lbs)

Can anyone please tell me:
1: Why do the Star BMW tires have different load ratings?
2: Is it okay to mismatch? (Front 96Y, Rear 100Y)
3: Why are the Star BMW fronts the heaviest, but the Star BMW for the rears are lighter?
4: Why do the front Star BMW tires missing the "Z" speed rating?
5: Which ones are you guys running??

Answers:
1: Because the "*" star marked BMW homologated spec tires are XL rated or "Extra-Load" rated

2: Yes. Load rating is a function of tire envelope air volume, tire geometry, body ply carcasse and summit area belt strength. Because the front and rear sizes are different, the load ratings are also different. However, generally speaking it's not good practice to mix Extra-Load and Standard Load rated tires - of the same size - on the same axle due to ply steer effects (drift & pull).

3. The table shows the non star marked 255/35ZR19 92Y is the lightest tire (23lbs) this is because it is standard load rated, and a smaller size than the rears. When comparing mass among the same sizes: Car makers usually have tire design mass targets due to rolling resistance requirements which sometimes forces a standard load or lower mass design strategy. Larger size tires are typically heavier than smaller size tires. XL tires are typically heavier than SL (standard load) tires due robustness of design and materials. I speculate the heavier star marked front may have more dense steel belts to improve steering response and handling as compared to generic mass market design solutions (and it's Extra-Load = XL).

4. Various reasons are possible answers: A) Typo by The Rack? B) The European Tire and Rim Association (E.T.R.T.O) design standards allows the Z to be omitted providing the Speed Index ("Y" in this case) is included in the mold size nomenclature. Alternatively, IF a ZR is included in the size nomenclature then the speed index can be optionally omitted i.e. 255/35ZR19 96 XL.

5. The star marked sizes. Because these tires are custom designed for the car chassis and optimized for handling at the Nurburgring, wet and dry traction, max circuit handling, residual aligning torque (drift), ply steer (pull), steering feel, rolling resistance, handling, noise, comfort etc. etc. ad nauseam..
.

[SilverSlug]

Originally Posted by DrFerry

Answers:
1: Because the "*" star marked BMW homologated spec tires are XL rated or "Extra-Load" rated

2: Yes. Load rating is a function of tire envelope air volume, tire geometry, body ply carcasse and summit area belt strength. Because the front and rear sizes are different, the load ratings are also different. However, generally speaking it's not good practice to mix Extra-Load and Standard Load rated tires - of the same size - on the same axle due to ply steer effects (drift & pull).

3. The table shows the non star marked 255/35ZR19 92Y is the lightest tire (23lbs) this is because it is standard load rated, and a smaller size than the rears. When comparing mass among the same sizes: Car makers usually have tire design mass targets due to rolling resistance requirements which sometimes forces a standard load or lower mass design strategy. Larger size tires are typically heavier than smaller size tires. XL tires are typically heavier than SL (standard load) tires due robustness of design and materials. I speculate the heavier star marked front may have more dense steel belts to improve steering response and handling as compared to generic mass market design solutions (and it's Extra-Load = XL).

4. Various reasons are possible answers: A) Typo by The Rack? B) The European Tire and Rim Association (E.T.R.T.O) design standards allows the Z to be omitted providing the Speed Index ("Y" in this case) is included in the mold size nomenclature. Alternatively, IF a ZR is included in the size nomenclature then the speed index can be optionally omitted i.e. 255/35ZR19 96 XL.

5. The star marked sizes. Because these tires are custom designed for the car chassis and optimized for handling at the Nurburgring, wet and dry traction, max circuit handling, residual aligning torque (drift), ply steer (pull), steering feel, rolling resistance, handling, noise, comfort etc. etc. ad nauseam..
.

Thank you for that. So you would recommend the Star labeled tires from above (96Y and 100Y) even though they technically fall right below the specs that OEM PSS tires came in (97Y and 101Y)?

[DrFerry]

Originally Posted by SilverSlug

Thank you for that. So you would recommend the Star labeled tires from above (96Y and 100Y) even though they technically fall right below the specs that OEM PSS tires came in (97Y and 101Y)?

#1 Best Option = Use the exact star marked OEM tire fitment (specific tire type model, load and speed index) designed and homologated for the car. Example: MPS2 and MPSS star marked.

#2 Option = Use star marked tire sizes of similar or better tire model and type - not necessarily or specifically designed for the exact car model - but preserving the load and speed indexes (whenever possible) from a very similar car model or chassis. Example: MPS4S or MPSS star marked.

#3 Option = Generic replacement market non OEM tire line product, non star marked in same or higher load and speed indexes designed to work well on a variety of car chassis. Example: MPSAS4 or MPSCUP2.

[SilverSlug]

So ultimately, the Star MPSS are better suited for E9X M3 than the Star MP4S?

I thought the 4S was an upgrade to the PMSS, no?

[DrFerry]

Originally Posted by SilverSlug

So ultimately, the Star MPSS are better suited for E9X M3 than the Star MP4S?

I thought the 4S was an upgrade to the PMSS, no?

When the E9X chassis and LCI variant face lifted models were being developed, MPS4S was not yet in existence. It means there is no custom specific OEM designed and homologated MPS4S fitments for the E9X M3 chassis. Only MPS2 and MPSS if I recall correctly were homologated for the E9X M3 chassis (I think). While it is true that MPS4S is an upgrade in technology to MPSS and MPS2, any star marked sizes in that product line are for other BMW chassis variants and not the E9X M3 (as far as I recall). You won't go wrong following the options logic I listed above earlier, while keeping in mind that stepping up to the newest technology product lines does mean stepping away from the custom designed OEM solution(s). Think of it this way: A custom made tailored suit fits better than a generic suit off the rack. While wear life, wet and dry grip are often improved with new product lines; what about the OEM performance levels of road noise, ride comfort, steering response, steering feel, steering delay, yaw damping, lateral firmness, mass, etc. etc. Are they preserved? Most people never notice any difference (better or worse) and consequently generic replacement market tires are enough. Moreover, people's tire performance priorities are different, because their budgets, driving styles, and tastes are often quite different. Ultimately the choice is yours.

[Drv4fun]

OEM 19” for E92 MY13 load rating was 93/98
Supplementary manual page 58.
If I remember correctly the MPSS came later after MY13, the star version came later for the M2 (same 245/265). (Note M2 had option for the sport cup 2 star tire in 245/265.)

As a side note the recommended snow tires had an XL load rating in the manual, summer tires don’t specify XL. My car had the Pirelli PZero and I dont see XL on the tires in my old pictures. The PZeros were great tires but got very loud near the end. Wet traction was poor the last 30%. They got so loud I thought the differential had gone bad. The MPSS have been solid. I had some Conti but were terrible- sold them after less than 1k miles. I also have M A/S 3+ - awesome wet traction and dry comparable to MPSS for daily driving. Other tires I have had are not worth mentioning.

Great input from everyone! Its too bad new tires aren’t made to prior car MY specs- they already have it-I suppose the Manufacturer would have to request it.

Check out MSP4s in 245/265 (factory size) not BMW star - it seems to be a good match to factory spec star tire.

Specifications

Michelin

Pilot Sport 4S

Size: 245/35ZR19
Service Description: (93Y)
Load Range: XL
Eco:Michelin Total Performance
UTQG: 300 AA A
Max Load: 1,433 lbs
Max Inflation Pressure:50 psi
Tread Depth:9.5/32"
Tire Weight: 23 lbs
Rim Width Range:8-9.5"
Measured Rim Width:8.5"
Section Width:9.8"
Tread Width:8.6"
Overall Diameter:25.8"
Revolutions Per Mile:807
Country of Origin: FRANCE


Size: 265/35ZR19
Service Description: (98Y)
Load Range: XL
Eco:Michelin Total Performance
UTQG: 300 AA A
Max Load: 1,653 lbs
Max Inflation Pressure:50 psi
Tread Depth:9.5/32"
Tire Weight: 27 lbs
Rim Width Range:9-10.5"
Measured Rim Width:9.5"
Section Width:10.7"
Tread Width:9.6"
Overall Diameter:26.3"
Revolutions Per Mile:790
Country of Origin: UNITED STATES OF AMERICA

Compare with the PZero (BMW star) still being made

Pirelli

P Zero

Size: 245/35ZR19
Service Description: (93Y)
Load Range: XL
UTQG: 220 AA A
Max Load: 1,433 lbs
Max Inflation Pressure:50 psi
Tread Depth:10/32"
Tire Weight: 24 lbs
Rim Width Range:8-9.5"
Measured Rim Width:8.5"
Section Width:9.9"
Tread Width:8.4"
Overall Diameter:25.9"
Revolutions Per Mile:800
Country of Origin: GERMANY

Size: 265/35ZR19
Service Description: (98Y)
Load Range: XL
UTQG: 220 AA A
Max Load: 1,653 lbs
Max Inflation Pressure:50 psi
Tread Depth:10/32"
Tire Weight: 25 lbs
Rim Width Range:9-10.5"
Measured Rim Width:9.5"
Section Width:10.4"
Tread Width:9.1"
Overall Diameter:26.3"
Revolutions Per Mile:822
Country of Origin: GERMANY

Note above specs taken from tirerack.

Very interested to see what you decided on. Please report back.