Sponsored by The Tire Rack

[///S65]

Originally Posted by 1fastdoc

I'm not sure exactly what you're asking. I suspect you mean from stock PS2's or Conti's to the PSS but same sizes? I can't really answer that one. Too soon on the newest setup. You'll have less understeer with a less staggered setup.

From a mathematical standpoint, the difference percentage wise between 255 to 275 is less than 245 to 265 but it's probably negligible.

Now, from the initial pic, you can see there is significantly more rubber on the 275 than the 265. The 245 and 255 look nearly identical IIRC. So, more rubber on the rear = greater effective stagger = more understeer. That's my rationale. But, I'm a doc, not an engineer, and I'm just making this shit up.

Sorry for the confusion. I was running on 245/265 PSS on the track and the car gave me a lot of understeer. They don't have much tread left so its time to replace them. I am still debating if I should step up to 255/275. I guess I will wait till you put more miles and track days on this setup.

[1fastdoc]

I would search a bit. There are a lot of people running the 255/275 combo.

[grantmax]

Reporting back on this topic. After putting some mileage on my awkward setup (245/275 PSS), the understeer is fairly ridiculous. Even with my 15/12 spacers. I'm swapping to 15/10 to help with looks and drive-ability.

The rear with 275s looks and feels great. There is so much grip. Unfortunately, the 245s up front can't keep up. I also don't like the way the car behaves now. The "fun factor" of the smaller tires in back made sliding around a breeze. The 275s chirp under hard acceleration but that's about it.

I'll be moving to 255s up front at the end of the month and will report back with a second update.

[FogCityM3]

The GTS also has hub centric spacers, probably by at least +10mm, which widens the track and reduces understeer.

Originally Posted by 1fastdoc

I'm quite happy with the 255/275 setup, the car feels solid.

Are you are aware that the ZCP wheels are the exact same as the M3 GTS wheels?

Are you also aware that the GTS comes shod with 255/285's?

As Larthal stated, mass production cars are all about compromise. Hate to tell you, but most M3's spend their entire lives docily driven on the street. Not mine.

Also, while they may fit the 220 wheels well, the 245/265's are stretched tight on the wider ZCP wheels. Hitting a good bump ruptured the sidewall on one of my front tires last year. The bigger size has a slightly meatier sidewall and it isn't stretched so thin.

I agree with Hujan, I think BMW kept the 245/265 despite the wider ZCP wheel for cost and simplicity. It's not the best compromise.

[Ant Man]

I'm fairly certain the GTS uses spacers in the front only (5mm) and for the sole purpose of providing more clearance for the suspension.

Someone asked about moving from 245/265 to 255/275 and if it would incease turn it. The front to rear ratios are very similar therefore the balance of the car is unlikely to be altered. Reducing the amount of front toe-in would allow the car to turn-in better.

[Richbot]

Weird the 265/40-18 PSS has the narrower grooves. Pictures here next to a 245/40-18:

[Richbot]

Photo didn't attach. Stupid app.

[AMG_LAWL]

I just bought 275's and I like them a lot better than the 265's. Plus all limerock m3's come with 255 front and 275 rear.

[Seattle M3]

Originally Posted by AMG_LAWL

I just bought 275's and I like them a lot better than the 265's. Plus all limerock m3's come with 255 front and 275 rear.

Are you sure of this? First I have ever heard that.

[Amirsm3]

Originally Posted by Richbot

Weird the 265/40-18 PSS has the narrower grooves. Pictures here next to a 245/40-18:

There are more grooves with the 265, though, so I'm guessing there's still the same volume of water being channeled.

[AMG_LAWL]

Yup, he bought it brand new from a BMW of Valencia in California. The car came stock with 255 front and 275 rear Contis. HE verified with the dealership and they said its not a mistake. My 275's in the rear feel really good on turns, it feels like it has a little more grip and less slip.

Originally Posted by Seattle M3

Are you sure of this? First I have ever heard that.

[LarThaL]

Originally Posted by Richbot

Calling the tires the car was fitted with from the factory optimal is like calling 414hp optimal. Adequate, yes, but improvement is always possible

Nobody said they were optimal. They are the best compromise given a variety of requirements for a street driven car. The analogy with the engine doesn't hold IMO.

[slicer]

Originally Posted by AMG_LAWL

.................Plus all limerock m3's come with 255 front and 275 rear.

Originally Posted by AMG_LAWL

Yup, he bought it brand new from a BMW of Valencia in California. The car came stock with 255 front and 275 rear Contis. HE verified with the dealership and they said its not a mistake....

Sorry but this is 100% inaccurate. The Limerock M3 came with the same tire size as all other M3's (245/265).

[LarThaL]

Originally Posted by slicer

Sorry but this is 100% inaccurate. The Limerock M3 came with the same tire size as all other M3's (245/265).

Agree. 245/265 for Limerock, unless the dealership changed the tires....which I doubt.

[Denk]

Only the GTS came with different size tires. Edition and Limerock wore the same old skinny's.

[AMG_LAWL]

Lol don't kill the messenger

Its not 100% inaccurate if the car came with them right? Whether or not the dealer slapped them on or manufacture.

You can call BMW in Valencia, CA and even speak to the general manager, his name is Mr. Sood. He knows me very well. You can even ask him, the tires came on the Limerock (255/275) from the manufacture. The dealership did not put these on themselves. Two limerock M3's left their dealership with those tires on them. I thought this was weird too because when my friend purchased it, I had my M3 at that time and I was running stock 245/265 on comp. We ALL thought it was super weird haha

Originally Posted by slicer

Sorry but this is 100% inaccurate. The Limerock M3 came with the same tire size as all other M3's (245/265).

[jerseygirl]

Originally Posted by 1fastdoc

I researched the hell out of this and debated for a while before deciding to upsize from the 265/35-19 to the 275/35-19. There is also another thread around here discussing the difference in weight (3 lb each) and the amount of rubber. I figured I'd snap the pick below to show how dramatically different they are. I had previously bumped the front up from 245 to 255 and definitely noticed it behaved better when entering a fast turn (street, haven't tracked it). It will be interesting to see how it feels when I go from a 255/265 setup to the new 255/275 setup. I suppose I'll have more understeer with the increased stagger.

Anyway, here they are. The 275 above is mounted.

i did the same two years ago. i thought it handled better too

[z3papa]

Originally Posted by LarThaL

Nobody said they were optimal. They are the best compromise given a variety of requirements for a street driven car. The analogy with the engine doesn't hold IMO.

I have seriously question any representation along this line. Michelin PS2's are basically good tires with a name brand the gives an impression but not great tires and the stagger is about building in intentional understeer. If you really like understeer, then you are good to go. Me -- I like a more neutral car which is less prone to understeer. If it were up to me, they'd have -2.5 camber up front and a square 275 setup and let me control any oversteer issues in the rear.

[maloo]

Originally Posted by 1fastdoc

Below are the tires/sizes I've run and how it felt. Bear in mind, they can't truly be directly compared because I also changed from PS2 to PSS. None of the tires were worn beyond half way when they were changed.

PS2 245/265: Nimble, quick turn in at lower speeds but some unpleasant understeer during a hotter turn. Came out of turn and got on it too quick (on a clean track), thus putting the ass end of the car before the front end. Not fun.

Sears tried to fix a leak and bubbled the sidewall on the 265 trying to get it off the wide rim. The 275's weren't available so I went to a 265 PSS.

PS2 245 / PSS 265: The ass end felt like it planted much better through turns. No track but took it to Tail of the Dragon and Cherohala skyway. Put 240 miles on the car before noon, in mostly wet conditions. Stability control NEVER came on. Understeer was still an issue at times on the back roads.

Blew my front tire hitting the junction between asphalt and concrete on a highway overpass. Bumped a size AND changed PS2 to PSS.

PSS 255/265: Definitely less understeer. I liked this setup but all of a sudden I found it much easier to get the ass end to kick a bit through turns. Never lost it but the stability control popped up from time to time. My car was wearing these tires when my friend spun it 180 on a highway and ate a guardrail. Decided it was time to get more staggered.

PSS 255/275: I've only had the car back on the road like this for about 100 miles. So far it feels well planted. It it not as nimble as the stock setup and I definitely feel it a little more in the wheel. However, the stability control has not tried to intervene they way it would on wet roads with the 255/265 setup.

If I were to keep it to basic daily driving without the need to take on/off ramps at triple digit speeds I would stay with the 245/265. But if that were the case I would put them on a Lexus, not an M3.

Thanks, great feedback. I'm staying with the 245/265 stock setup.

[Amirsm3]

Originally Posted by AMG_LAWL

Lol don't kill the messenger

Its not 100% inaccurate if the car came with them right? Whether or not the dealer slapped them on or manufacture.

You can call BMW in Valencia, CA and even speak to the general manager, his name is Mr. Sood. He knows me very well. You can even ask him, the tires came on the Limerock (255/275) from the manufacture. The dealership did not put these on themselves. Two limerock M3's left their dealership with those tires on them. I thought this was weird too because when my friend purchased it, I had my M3 at that time and I was running stock 245/265 on comp. We ALL thought it was super weird haha

Just because someone works at a BMW dealership doesn't make them an expert on any particular model.
http://www.autoblog.com/2013/07/25/2...view/#image-14

That shows a 245/35/19 out front - and if you look at the other images, you can see a 265 out back. The car may have come like that to the dealership, but the car did not come from the factory with a 255/275 set up.

[1fastdoc]

Originally Posted by maloo

Thanks, great feedback. I'm staying with the 245/265 stock setup.

You're welcome. I searched for a long time trying to figure out what would work best so I hope my experience helps others.

BTW, if it wasn't clear in the last sentence, if I were doing it again for the M3, I would go to 255/275 every time. The steering is a little heavier and road fluctuations are more noticeable but it definitely felt more solid. If you plan to keep the car under 100 mph, then stick with the factory size.

[Helmsman]

Originally Posted by 1fastdoc

You're welcome. I searched for a long time trying to figure out what would work best so I hope my experience helps others.

BTW, if it wasn't clear in the last sentence, if I were doing it again for the M3, I would go to 255/275 every time. The steering is a little heavier and road fluctuations are more noticeable but it definitely felt more solid. If you plan to keep the car under 100 mph, then stick with the factory size.

Thanks from me too Doc, so I'll try with 255/275 when changing for Summer wheel next time...😊

Ps. Got fully used to the truck, or started to look for another M3 yet mate?