BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Wheels + Tires Sponsored by The Tire Rack
  TireRack

KEEP M3POST ALIVE BY DOING YOUR TIRERACK SHOPPING FROM THIS BANNER LINK!
Post Reply
 
Thread Tools Search this Thread
      01-20-2012, 03:23 PM   #1
Definitive
definitivecars.com
Definitive's Avatar
United_States
352
Rep
3,833
Posts

Drives: Elsa - 2015 F80 M3 - YMB/SS
Join Date: Aug 2006
Location: So Cal

iTrader: (3)

Garage List
PS2 Question for Smart tire people.

So I was looking at my tires on the car and thought all of a sudden that I was somehow sold two right, or two left tires...

I know this sounds weird already, because the next thing I thought to myself is that I KNOW that there is no left or right with PS2's, just an outside and inside.

So Im thinking to myself. How is it possible that one of the best tires out there has tread that goes in opposite directions on the same axle. wouldn't this cause tread wear issues, handling issues, traction issues and who knows what else.

Take a look at the picture before and pretend your looking at them on the back of a car. To me the tread seems to be totally opposite. Like one tire would have better traction than the other.



Am I the only one that is noticing this now after years of running these tires? Can someone try to explain how "physically" this works ok? To me its like if the direction of the holes on our break rotors when opposite ways from right to left. Wouldent that cause different performance?

Embarrassed,
D
Appreciate 0
      01-20-2012, 07:36 PM   #2
Definitive
definitivecars.com
Definitive's Avatar
United_States
352
Rep
3,833
Posts

Drives: Elsa - 2015 F80 M3 - YMB/SS
Join Date: Aug 2006
Location: So Cal

iTrader: (3)

Garage List
Wow, I thought for sure I would get some immediate responses or flamings. Lol but not crickets.

D
Appreciate 0
      01-20-2012, 07:51 PM   #3
paradocs98
Lieutenant Colonel
paradocs98's Avatar
United_States
392
Rep
1,519
Posts

Drives: M2C
Join Date: May 2009
Location: NY

iTrader: (0)

Okay, I'll bite...

This is normal, even though it looks strange. The PS2s are asymmetric (there is a different tread compound and pattern inboard vs. outboard) but not directional (it does not matter which direction the tire travels). So all PS2s are the same--there is no specific left-side tire vs. right-side tire--so the outer pattern runs opposite on one side vs. the other (as does the inner pattern). As to why this does not create an issue, I have no idea--I'd like to hear a good explanation, too.

I first noticed this a few years ago with the PS2s on my former car. I immediately began checking out every sports car I could find to see if this was the case with their PS2s, too. I thought maybe I had incorrect tires on one side! Up until that point, I had only been familiar with symmetric, directional tires like the original Pilot Sport and the Bridgestone S03 Pole Positions. With those tires, there is no inboard vs. outboard, but there is certainly a correct direction of rotation!

Once you've noticed this, though, you'll see it everywhere. This asymmetric, non-directional pattern is also used on the OEM PZeros that came on my M3, and on the new Michelin Pilot Super Sports. In fact, I think that asymmetric, directional tires are pretty rare, since, if used in a staggered setup, there is literally a specific LF tire, a specific RF tire, a specific LR tire, etc. It makes for a very careful phone call when you need to replace one tire: "I need a 275/30-19 LEFT-sided tire..."

So it does seem weird that the tread pattern runs in different directions on one side of the car relative to the other with the PS2, PSS, PZero, etc., but I assume the engineers know what they're doing.
Appreciate 0
      01-20-2012, 09:27 PM   #4
bigjae1976
Major General
bigjae1976's Avatar
1567
Rep
8,074
Posts

Drives: 11 E90 M3 Individual
Join Date: Mar 2006
Location: Houston, TX

iTrader: (22)

Garage List
2004 BMW M3  [4.50]
2011 BMW E90 M3  [5.25]
2013 BMW 328i  [5.00]
Quote:
Originally Posted by paradocs98
Okay, I'll bite...

This is normal, even though it looks strange. The PS2s are asymmetric (there is a different tread compound and pattern inboard vs. outboard) but not directional (it does not matter which direction the tire travels). So all PS2s are the same--there is no specific left-side tire vs. right-side tire--so the outer pattern runs opposite on one side vs. the other (as does the inner pattern). As to why this does not create an issue, I have no idea--I'd like to hear a good explanation, too.

I first noticed this a few years ago with the PS2s on my former car. I immediately began checking out every sports car I could find to see if this was the case with their PS2s, too. I thought maybe I had incorrect tires on one side! Up until that point, I had only been familiar with symmetric, directional tires like the original Pilot Sport and the Bridgestone S03 Pole Positions. With those tires, there is no inboard vs. outboard, but there is certainly a correct direction of rotation!

Once you've noticed this, though, you'll see it everywhere. This asymmetric, non-directional pattern is also used on the OEM PZeros that came on my M3, and on the new Michelin Pilot Super Sports. In fact, I think that asymmetric, directional tires are pretty rare, since, if used in a staggered setup, there is literally a specific LF tire, a specific RF tire, a specific LR tire, etc. It makes for a very careful phone call when you need to replace one tire: "I need a 275/30-19 LEFT-sided tire..."

So it does seem weird that the tread pattern runs in different directions on one side of the car relative to the other with the PS2, PSS, PZero, etc., but I assume the engineers know what they're doing.
Disappointed, no smart ass comment .

OP, I did the same thing...no worries
__________________
2018 F30 320iX Melbourne Red
2011 E90 M3 Monte Carlo Blue
2004 E46 M3 Imola Red
2000 E36/7 Z3 Steel Blue
Appreciate 0
      01-20-2012, 09:51 PM   #5
bchang2001
Lieutenant
18
Rep
463
Posts

Drives: e92 M3
Join Date: Mar 2011
Location: OC,CA

iTrader: (5)

you tires are going the wrong way!
Appreciate 0
      01-23-2012, 01:56 PM   #6
ben@tirerack
M3Post Supporting Vendor
87
Rep
964
Posts

Drives: 740i
Join Date: Mar 2008
Location: South Bend, IN

iTrader: (0)

Paradocs had great info. I'll add a couple notes. I am NOT a tire engineer. I sell a lot of tires, I test a lot of tires, I think about tires pretty much all day, but don't expect lots of calculations and formulas.


When a tire is running 'backwards', the main concern is water evacuation, and in this case water evacuation is straight through the tread via the main circumfrential grooves.

First and foremost, don't get bogged down in the minutia: the PS2 is basically a straight-rib tread design. It consists of circumferential grooves of varying width spaced across the tread of the tire. The ribs between the grooves are basically solid. Water evacuation, the main area of concern if a tire was running 'backwards', is straight through the tread via the main circumfrential grooves.

There are minor diagonal elements in the tire, but they are not as deep or wide as the circumfrential elements. The bigger diagonal grooves are on the shoulders, and they are very close to horizontal, making them equally effective going one way as the other. Some of the elements may do better than others in one direction or the other, but the net effect is equivalent performance going either way.

This is especially happy news for those who like to drive really fast in reverse.
__________________
_______________________________________________
I have accepted a new position at Tire Rack and am no longer in the sales department. gary@tirerack.com is available to assist with M3 questions.
Appreciate 0
      01-24-2012, 09:24 AM   #7
paradocs98
Lieutenant Colonel
paradocs98's Avatar
United_States
392
Rep
1,519
Posts

Drives: M2C
Join Date: May 2009
Location: NY

iTrader: (0)

Quote:
Originally Posted by ben@tirerack View Post
This is especially happy news for those who like to drive really fast in reverse.
Good one!

TowMater, ya hear that? Ben's got new shoes for you!!
Attached Images
 
Appreciate 0
      01-24-2012, 10:40 AM   #8
Definitive
definitivecars.com
Definitive's Avatar
United_States
352
Rep
3,833
Posts

Drives: Elsa - 2015 F80 M3 - YMB/SS
Join Date: Aug 2006
Location: So Cal

iTrader: (3)

Garage List
Haha, Thanks for the responses guys.
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 08:10 AM.




m3post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST