[greentrbo95gst]

Anyone tried it? Just wondering if the trans would freak out.
My ferrari doesn't like off factory sizes for the front and rear and throws bunch of codes.

[GladiatorOwner]

Shouldn't. Tire needs to be very close in diameter as dialed in to oem. I think front and rear need to be within .5 inch. It's when diameter sizes are more than inch or so the system doesn't like it. There are specific acceptable ranges but I forget the actual numbers.

When you go from 20 to 21s, the diameter should be close. That's why aspect ratio goes from 30 to 25, etc. but I think you know that.

[shawnhayes]

Originally Posted by GladiatorOwner

Shouldn't. Tire needs to be very close in diameter as dialed in to oem. I think front and rear need to be within .5 inch. It's when diameter sizes are more than inch or so the system doesn't like it. There are specific acceptable ranges but I forget the actual numbers.

When you go from 20 to 21s, the diameter should be close. That's why aspect ratio goes from 30 to 25, etc. but I think you know that.

[Do you know what square even means?] - *edit* - I misunderstood what GladiatorOwner meant. "Shouldn't" was in response to "will it make trans freak out", not "anyone tried it"

It's when the front and rear tires are THE SAME, which means they are PERFECT.

For the OP, I'm on square front and rears on the track, both wheels and tires the same. Works awesome. Stable to 160MPH sustained.

And my around town/track hybrid are square Pilot Sport 2's on OEM rims. Also perfect.

Shawn

[GladiatorOwner]

Originally Posted by shawnhayes

Do you know what square even means?

It's when the front and rear tires are THE SAME, which means they are PERFECT.

For the OP, I'm on square front and rears on the track, both wheels and tires the same. Works awesome. Stable to 160MPH sustained.

And my around town/track hybrid are square Pilot Sport 2's on OEM rims. Also perfect.

Shawn

Holy shit, do you even know how to read or comprehend? Wtf do you think “shouldn’t” means. I know it works since I ran a “square” setup during the winters on 2 M5s and an M6GC.

[shawnhayes]

Originally Posted by GladiatorOwner

Holy shit, do you even know how to read or comprehend? Wtf do you think “shouldn’t” means. I know it works since I ran a “square” setup during the winters on 2 M5s and an M6GC.

"

Well, shit. I thought you were "Shouldn't" to "Anyone tried it", not "Will it make the trans freak out". The further expounding on differences between front and rear led me further down the path that you meant he shouldn't try different than OEM.

My apologies.

To the OP, so now you know, two people have the square setup.

Shawn

[greentrbo95gst]

Thanks! I Didn't mean to start a war, but appreciate any feedback.
I ran square winter setup with no issues, but now I am planning on doing square Mickey Thompson setup with lightweight 19" wheels.

https://www.mickeythompsontires.com/.../et-street-s-s

285/35R19 with 26.9 diameter

[shawnhayes]

Originally Posted by greentrbo95gst

Thanks! I Didn't mean to start a war, but appreciate any feedback.
I ran square winter setup with no issues, but now I am planning on doing square Mickey Thompson setup with lightweight 19" wheels.

https://www.mickeythompsontires.com/.../et-street-s-s

285/35R19 with 26.9 diameter

I just misinterpreted a word. No war, it was late and I misread it. Mea culpa.

I'm with you. I have all square setups now. My 285/30r20 on square 10" wheels requires a 5mm spacer in front to clear the uprights. The rears do just fine. I suspect with a 5mm offset greater it would clear fine, but they're pretty close to the fenders now, and I don't want to be doing any fender rolling.

Shawn

[GladiatorOwner]

Originally Posted by shawnhayes

I just misinterpreted a word. No war, it was late and I misread it. Mea culpa.

I'm with you. I have all square setups now. My 285/30r20 on square 10" wheels requires a 5mm spacer in front to clear the uprights. The rears do just fine. I suspect with a 5mm offset greater it would clear fine, but they're pretty close to the fenders now, and I don't want to be doing any fender rolling.

Shawn

No harm. All good bro. I didn’t need to jump either. I’ve never tried all square for summer. Interesting option.

[pbonsalb]

The ABS and traction control are programmed for the factory front/rear diameter differential. I have not looked up what that is. Increasing or decreasing that differential obviously affects ABS and traction control, but may be so minimal that only a track driver could notice and even then the change could slightly improve or worsen handling. Since BMW apparently allows square winter tires, eliminating the variation can’t be bad.

[shawnhayes]

Originally Posted by pbonsalb

The ABS and traction control are programmed for the factory front/rear diameter differential. I have not looked up what that is. Increasing or decreasing that differential obviously affects ABS and traction control, but may be so minimal that only a track driver could notice and even then the change could slightly improve or worsen handling. Since BMW apparently allows square winter tires, eliminating the variation can’t be bad.

All wheel drive cars with any mechanical links from front to back ALWAYS do better with perfectly matched front and rear outer diameter's

I'll bet pretty good money, that if we look it up, the stock tires are ALMOST perfectly the same outer diameter as each other.

Because in winter, as above, the BMW winter setup is perfectly square. When, of course, the handling most often means the difference between superstar and super dud. Or worse, hurt really bad.

Just "been there, done that".

Shawn

[pbonsalb]

About 2/10 inch difference for 285/35/30 and 275/36/20, which is only about 8 revolutions per mile, so the difference is indeed so minuscule it would not matter if you did away with it and went square.

[shawnhayes]

Originally Posted by pbonsalb

About 2/10 inch difference for 285/35/30 and 275/36/20, which is only about 8 revolutions per mile, so the difference is indeed so minuscule it would not matter if you did away with it and went square.

Superb work. Thank you.

I came from the GT-R world, where the stock GT-R tires were 255/40R20's and 285/35R20's which, from the OEM manufacturer, differed by only 2 revolutions per mile. In a quest for track tires, either you got it near perfect, or you ate the center differential.

The only REAL test (even if the OEM manufacturer said they were perfect) was to mount and balance the tires and do an actual dry rollout of the car to make sure they were off by less than a very miniscule amount.

For those of us who didn't want to buy a set of tires that you might would not be able to use, the 285's fit both the front and rear rims, so a lot of us just did that.

I carried my habits over to this M5.

Square=safe

Shawn