[ZM2]

I just wanted to point out that Michelin now has a BMW Star spec 255/35/19 PS4S available: https://www.tirerack.com/tires/tires...XLV3&tab=Specs

I don't know the exact differences b/n this BMW Star spec and the regular version, but often times the car manufacturers will ask for a different tread block pattern or a slight variation in width for the same size tire to better suit their cars' specific suspension, wheel, and handling designs.

I'll ping Michelin & Tirerack to see if I can get an answer, but if anyone knows or can compare a regular 255/35 PS4S to the 255/35 PS4S BMW Star spec, please let us know!

[five3three]

It isn't offered in the 275 size which most people would pair up with the 255. I guess that's why I wasn't offered that as an option yesterday when I ordered a set of mps4s from tire rack that will arrive today. I guess they don't mix and match.

I don't know the difference though.

[ZM2]

Yeah, TR won’t mix/match with Star/non-Star, even tho it’s no big deal. There’s generally not a huge difference bn Star/non-Star, but it’s always good to know the specs and make your own call.

For instance, I think the last 255 PSS Star had larger channels for water than the reg PSS. That’s not what I’d want from my PS4S. Altho, the 295/35/19 BMW Star was designed to fit 10” wheels, so that’s a good thing if you want that tire and size.

Who knows how Star’s impact all the different setups we’re each running, but I’ll try to get the specs so we can each decide on our own.

I’m thinking they’ll come out with a 275/35/19 PS4S Star, but not quite sure. Probably depends on what tire they’re spec’ing for the next M3/4.

[ZM2]

Lame answer from Michelin. I'll see if I can get more from them:

"The compound is slightly differently and that would affect the handling and performance. That Star means that tire has been approved by BMW. Also to get into the specifics of the tires that would be considered proprietary information and not given."

[ZM2]

And, shot down by TR:

"When a tire manufacturer works in collaboration with a vehicle manufacturer to produce a spec tire by tuning a tire already on the replacement market like the PS4S, any changes that are made internally to the tire beyond what a standard spec sheet will tell you are proprietary information between the tire manufacturer and the vehicle manufacturer. They do not share specifics on changes for OEM tuned tires, so the only way to get an answer to that question would be to know an insider engineer at Michelin or BMW that would be willing to break secrecy and give you the details. We do not even have that info."

I figured they wouldn't know. I'll try my BMW contacts. If you guys have any, ping them.

[ZM2]

My BMW contact: "Let me do an inquiry for you about the tire question. Standby."

We shall see!

[five3three]

One problem I can see is that if there is any material change that could affect driving dynamics from the standard ones, it would not weigh much on the overall reviews (since they are combined between star spec and not). I am not sure I would simply take BMW's word that this is better as they could have gotten it wrong. I do however trust overall tire rack reviews and ratings.

[ZM2]

Yeah, if it’s simply a compound difference, who knows what the performance difference will be like without driving them back to back and over many miles.

If it’s a clear tread pattern difference (more/less water groves), that would certainly be noticeable.

To correct what I mentioned earlier, I was thinking of the Mercedes spec 265/35/19 PSS that a lot of M3/4 guys run upfront that has wider groves for rain. Again, not what I’d want, but it was designed for a 9” wheel for anyone that wants to run that upfront.

I’ve been running a regular 265 PS4S on the front OEM wheels for a while, and while the grip is great, I don’t like the turn in. So, will be going back to 255.

[Karmic Man]

Interesting. Please keep us posted with updates as I am also looking at tyre options beyond the staggered 245/260 setup.

[paradocs98]

Originally Posted by ZM2

I’ve been running a regular 265 PS4S on the front OEM wheels for a while, and while the grip is great, I don’t like the turn in. So, will be going back to 255.

Do you think the turn-in suffers because the 265 is a bit too wide for the width of the OEM front wheel, causing some shifting of the tire on the wheel or decreasing overall stiffness/crispness? It would be interesting to compare with a 265 front tire on a 0.5" wider front wheel.

[ZM2]

Originally Posted by paradocs98

Do you think the turn-in suffers because the 265 is a bit too wide for the width of the OEM front wheel, causing some shifting of the tire on the wheel or decreasing overall stiffness/crispness? It would be interesting to compare with a 265 front tire on a 0.5" wider front wheel.

That’s absolutely what it is. I run 265s on my 9.5” track wheels. Turn in feels great.

[paradocs98]

Originally Posted by ZM2

That’s absolutely what it is. I run 265s on my 9.5” track wheels. Turn in feels great.

Good data--thanks. When I had an E90 M3 I ran a 275/35-18 track setup all around on 18x10 wheels. It was fantastic.

[ZM2]

Some of the M3/4 guys are helping out on this (some aren’t). Bottom line, we don’t want to use the new 255 Star Spec 4S:

https://f80.bimmerpost.com/forums/sh....php?t=1602752

[omasou]

I tried the 255/275 on the M2 and other than less stretch, I didn't find any great improvement in handling or grip. In fact, I think it was the opposite.

[ZM2]

Originally Posted by omasou

I tried the 255/275 on the M2 and other than less stretch, I didn't find any great improvement in handling or grip. In fact, I think it was the opposite.

Depends on your driving situ. Around town there's not much difference.

If you're a the limit, 255/275 will provide more lateral grip, and the 275 gives a tiny bit more acceleration grip. 245/265 is better in heavy rain, tho.

I run 255/285. That gives me the best mix of at limit grip on the OEM wheel sizes for my tune.

[omasou]

Originally Posted by ZM2

Depends on your driving situ. Around town there's not much difference.

If you're a the limit, 255/275 will provide more lateral grip, and the 275 gives a tiny bit more acceleration grip. 245/265 is better in heavy rain, tho.

I run 255/285. That gives me the best mix of at limit grip on the OEM wheel sizes for my tune.

Which 285 do you run? The 35 or 30? In a different thread someone said the difference was too large?

I have the MP coilovers. Do you know if the 255/285 rubs w/o excessive camber? I didn't see a definite answer in the threads that I have read.

[ZM2]

Originally Posted by omasou

Which 285 do you run? The 35 or 30? In a different thread someone said the difference was too large?

I have the MP coilovers. Do you know if the 255/285 rubs w/o excessive camber? I didn't see a definite answer in the threads that I have read.

I run the 285/35 to keep things more comfortable around town. The 285/35 will rub if you're lowered more than 17mm or so, have a full trunk and rear passenger, and hit a decent sized bump. I'm on Dinan HAS and had to raise it back up some after starting with a 23mm drop.

If you're at 20mm with the more stiffly sprung MP's, I think you'd be right on the edge of rubbing or not, assuming you aren't loaded down like I mentioned. I'd bet it'd work, tho.