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
      04-06-2009, 01:29 PM   #1
TRZ06
Captain
 
TRZ06's Avatar
 
Drives: 08' IB E90 M3
Join Date: Apr 2007
Location: Bay Area, CA

Posts: 652
iTrader: (0)

Why 18's over 19's for better handling?

I don't understand why the 18's would handle better than 19's.

The 19"s have a lower profile sidewall to keep the tire from rolling too much during hard cornering, thereby keeping more tire to the ground. The lower profile makes the car feel more stable and planted with less roll.

I don't get why a 40's series tires is even offered on the M.

Look at all the Ferraris, Porsches, Lambo's, Corvettes, they are using anything from 35 down to 25 series.

They ONLY reason I can see is weight. If you take the weight out of the equation, I would think a 35" 19" would corner better that a 40" 18"

Comments......?
__________________
11' Cyber Gray Corvette Grand Sport
PREVIOUS:
08' M3 Interlagos Blue: 6sp, Tech. & Premium Package
07' 335i E90: KWV2, H&R Sways, SSTT
01' & 04' Corvette Z06
TRZ06 is offline   United_States
0
Reply With Quote
      04-06-2009, 01:43 PM   #2
richardg
Major
 
richardg's Avatar
 
Drives: e36M / e92M / e36 328i
Join Date: Jul 2006
Location: Bloomfield Hills Mi.

Posts: 1,310
iTrader: (5)

Quote:
Originally Posted by TRZ06 View Post
I don't understand why the 18's would handle better than 19's.

The 19"s have a lower profile sidewall to keep the tire from rolling too much during hard cornering, thereby keeping more tire to the ground. The lower profile makes the car feel more stable and planted with less roll.

I don't get why a 40's series tires is even offered on the M.

Look at all the Ferraris, Porsches, Lambo's, Corvettes, they are using anything from 35 down to 25 series.

They ONLY reason I can see is weight. If you take the weight out of the equation, I would think a 35" 19" would corner better that a 40" 18"

Comments......?
You have to remember that the sidewall measurement is a ratio of how wide the tire is. For all the cars you mentioned they have very wide tires. Especially Lamborghinis and Corvettes. Another example is a bike tire. Most people that do not know how sidewall measurements work would think that a bike has an extremely low profile. In reality a bike has HUGE profile since the tires are almost as thick as they are wide.

Also I would think that the weight you save would work better for you with a smaller wheel. I am not sure but I believe weight that rotates can have a huge affect on the car so every pound counts significantly.
richardg is offline  
0
Reply With Quote
      04-06-2009, 04:37 PM   #3
PunjabiM3
Lieutenant Colonel
 
PunjabiM3's Avatar
 
Drives: R8 5.2 6MT
Join Date: Mar 2008
Location: Oro Valley, AZ

Posts: 1,776
iTrader: (1)

F1 cars run tires with HUGE sidewalls...I wonder why...
__________________
2012 Audi R8 V10, 6MT, Suzuka Gray, Larini Clubsport exhaust, Klassen M52R, GMG springs, Satin Black badges
2012 Audi A6 3.0T Prestige, Moonlight Blue
2014 BMW 528i, Space Gray
Previous: 11 e82 1M, Several 911's & M3's
PunjabiM3 is offline   India
0
Reply With Quote
      04-06-2009, 04:40 PM   #4
PunjabiM3
Lieutenant Colonel
 
PunjabiM3's Avatar
 
Drives: R8 5.2 6MT
Join Date: Mar 2008
Location: Oro Valley, AZ

Posts: 1,776
iTrader: (1)

You will get better overall handling from a 40 series tire than a 30 series in the same width unless maybe you are on a road that is as smooth as glass. Like stated above, the width of a tire makes a huge difference in the fatness of the sidewall. A 285/30 has a fatter/larger sidewall than a 225/30...you can easily tell by just looking at the two tires even though both are a 30 series tire.
__________________
2012 Audi R8 V10, 6MT, Suzuka Gray, Larini Clubsport exhaust, Klassen M52R, GMG springs, Satin Black badges
2012 Audi A6 3.0T Prestige, Moonlight Blue
2014 BMW 528i, Space Gray
Previous: 11 e82 1M, Several 911's & M3's
PunjabiM3 is offline   India
0
Reply With Quote
      04-06-2009, 05:18 PM   #5
TRZ06
Captain
 
TRZ06's Avatar
 
Drives: 08' IB E90 M3
Join Date: Apr 2007
Location: Bay Area, CA

Posts: 652
iTrader: (0)

Ok, I get the sidewall ratio thing, but then why do all exotic supercars use thin sidewalls?

Anybody look at the side profiles (regargless of series) of the new Porsches, Ferrari, Lambo, etc. They are not even close to having the kind of sidewall that the stock 18" tires have on the M3.

Now the 19" sidewalls on the M3 look about right with the supercars, but the 18" don't, their sidewalls are definately taller then the supercars.

My thoughts on the 40 series on the 18" thus far are that once in the corner they stick well, but that initial transition into the corners, you can feel the sidewalls flex and that lessens the quick turn-in response.
__________________
11' Cyber Gray Corvette Grand Sport
PREVIOUS:
08' M3 Interlagos Blue: 6sp, Tech. & Premium Package
07' 335i E90: KWV2, H&R Sways, SSTT
01' & 04' Corvette Z06
TRZ06 is offline   United_States
0
Reply With Quote
      04-06-2009, 06:29 PM   #6
FStop7
I like cars
 
FStop7's Avatar
 
Drives: M6
Join Date: Oct 2008
Location: Newbury Park, CA

Posts: 5,059
iTrader: (3)

Quote:
Originally Posted by PunjabiM3 View Post
F1 cars run tires with HUGE sidewalls...I wonder why...
because the tire is a very big part of the suspension on those open wheel cars.

Quote:
Ok, I get the sidewall ratio thing, but then why do all exotic supercars use thin sidewalls?
Because it looks good.
__________________
FStop7 is offline   Vatican City State
0
Reply With Quote
      04-07-2009, 12:11 AM   #7
JAJ
Captain
 
Drives: 2014 Shelby GT500
Join Date: Apr 2008
Location: Vancouver, BC

Posts: 927
iTrader: (4)

Who said that the 18's perform better than the 19's? I saw a quote about that earlier when the E9x M3 was first released, but it was unattributed. It might not be true.

I will say that the 18's ride better than the 19's if you don't have EDC. Do they handle better? I have no idea.
JAJ is offline  
0
Reply With Quote
      07-19-2009, 10:34 AM   #8
x838nwy
Private First Class
 
Drives: nothing right now...
Join Date: Jun 2009
Location: Thailand

Posts: 178
iTrader: (0)

Quote:
Originally Posted by PunjabiM3 View Post
F1 cars run tires with HUGE sidewalls...I wonder why...
It's in the regulations. Wheel diameters, tyre diameters, widths etc.

Quote:
Originally Posted by TRZ06 View Post
Ok, I get the sidewall ratio thing, but then why do all exotic supercars use thin sidewalls?

Anybody look at the side profiles (regargless of series) of the new Porsches, Ferrari, Lambo, etc. They are not even close to having the kind of sidewall that the stock 18" tires have on the M3.

Now the 19" sidewalls on the M3 look about right with the supercars, but the 18" don't, their sidewalls are definately taller then the supercars.

My thoughts on the 40 series on the 18" thus far are that once in the corner they stick well, but that initial transition into the corners, you can feel the sidewalls flex and that lessens the quick turn-in response.
In my experience a taller sidewall will generally give you a more progressive feeling of the grip limit of the tyre. The taller side-walls will also cope better with bumps including apexes and other circuit furniture.
x838nwy is offline  
0
Reply With Quote
      07-19-2009, 10:53 AM   #9
sgar0777
Private
 
sgar0777's Avatar
 
Drives: 2009 E92 M3 AW/BLK 6MT
Join Date: Oct 2008
Location: Alpharetta, Ga.

Posts: 75
iTrader: (0)

I suspect that it is significantly more complicated than we think, and that you can not make a blanket statement about 18" vs. 19" tires. If we were able to test the two sizes side by side in various road conditions, temps, etc. I would wager that the 18's are better in some circumstances and 19's are better in others ON THE M3. Any conversations about another car brings too many variables in to play that can not be accounted for.
sgar0777 is offline   United_States
0
Reply With Quote
      07-20-2009, 04:27 AM   #10
bigjae1976
That's what she said...
 
bigjae1976's Avatar
 
Drives: 11 E90 M3 Individual
Join Date: Mar 2006
Location: Milwaukee, WI

Posts: 5,411
iTrader: (12)

Garage List
2004 BMW M3  [4.50]
2011 BMW E90 M3  [5.00]
2013 BMW 328i  [5.00]
The tires are part of the suspension. Some might do better with an small diameter wheel and larger sidewall and vice versa.

For me it really comes down to cost and selection. There are a LOT more choices at MUCH lower prices for 18" tires vrs 19" tires.
__________________


Sponsored by Momentum BMW #593...We Bleed BMW BLUE!
bigjae1976 is offline  
0
Reply With Quote
      07-20-2009, 05:34 AM   #11
bobbyd1961
Banned
 
Drives: 2009 M3 sedan LeMans Blue
Join Date: Jun 2009
Location: new jersey

Posts: 2,411
iTrader: (0)

Quote:
Originally Posted by TRZ06 View Post
I don't understand why the 18's would handle better than 19's.

The 19"s have a lower profile sidewall to keep the tire from rolling too much during hard cornering, thereby keeping more tire to the ground. The lower profile makes the car feel more stable and planted with less roll.

I don't get why a 40's series tires is even offered on the M.

Look at all the Ferraris, Porsches, Lambo's, Corvettes, they are using anything from 35 down to 25 series.

They ONLY reason I can see is weight. If you take the weight out of the equation, I would think a 35" 19" would corner better that a 40" 18"

Comments......?
the 19 rims so much nicer and the car handles fantastic and takes bumps 1000 times better than my 335 xi did with 18s
bobbyd1961 is offline  
0
Reply With Quote
      07-20-2009, 10:26 AM   #12
Trier Germany
Banned
 
Drives: 2009 E-90 M3 space gray
Join Date: Nov 2008
Location: Deutschland KreisTrier auf Autobahn 64 & Tucson AZ

Posts: 1,085
iTrader: (1)

Did your 335 have RFT? I f so of course there going to feel un comfprtable!

335 18''s RFT versus M3 19''s ps2 = apples and oranges. Go drive an M3 with 18''s oh so comfortable on the road and on the track.


Plus tire manufacyures dont have a huge selection of competion tires in 19''s for the M3 only in 18''s.
Trier Germany is offline   Luxembourg
0
Reply With Quote
      07-20-2009, 01:20 PM   #13
KonigsTiger
Racying Dynamics
 
KonigsTiger's Avatar
 
Drives: E92M3 RS46 Club Sport, others
Join Date: Jan 2008
Location: Dweller

Posts: 4,398
iTrader: (0)

Quote:
Originally Posted by Trier Germany View Post
Did your 335 have RFT? I f so of course there going to feel un comfprtable!

335 18''s RFT versus M3 19''s ps2 = apples and oranges. Go drive an M3 with 18''s oh so comfortable on the road and on the track.


Plus tire manufacyures dont have a huge selection of competion tires in 19''s for the M3 only in 18''s.
Well, you can find R-Compound/competition tires in 19" such as the Pilot Sport Cup and the Pirelli P-Zero Corsa System (soon to be Pirelli Triumfo). Granted, not a huge collection but as far as I am concerned you only need one for our cars and this fit just fine in 19".

Also, I know the 20" wheels on the M3 leaves sooo little side wall that its difficult for the tire to morph into an appropriate contact area when g forces act on it, this is at least why 19" is better than 20". Now, how much improvement (other than comfort) there is from 19" to 18" I donīt know. There is also the matter of fitting large brakes and not many 18" wheels will allow fitment of competition brakes.
__________________
==================================================
KonigsTiger is offline  
0
Reply With Quote
      07-22-2009, 11:27 AM   #14
dcstep
Brigadier General
 
Drives: '09 Cpe Silverstone FR 6MT
Join Date: Nov 2008
Location: Colorado

Posts: 4,882
iTrader: (0)

Garage List
2009 M3  [4.00]
I'll be using 30-series, 18" tires for my autocross set up next year. I'll be going to a 10" to 10.5" rear wheel to allow as much tire as possible back there, to gain acceleration, since AX is mostly run in 2d gear and I now spin my 19" wheel/tire set at will anywhere on the course. The low profile will give both a wider contact patch and stiffer sidewall. The front tires will also be 30-series and about 20mm narrower than the backs, to maintain balance.

The added advantage of 18", 30-series tires will be that the final drive ratio will be slightly higher numerically, improving mid-gear acceleration.

For street, I'll be staying with the 19" factory option, forged wheels in summer and 18" factory wheels, with snow tires for winter. I think these are the best compromise of ride and handling, where my AX setting is aimed at acceleration and handling with no concern for ride.

Dave
__________________
dcstep is offline   United_States
0
Reply With Quote
      07-22-2009, 12:51 PM   #15
KonigsTiger
Racying Dynamics
 
KonigsTiger's Avatar
 
Drives: E92M3 RS46 Club Sport, others
Join Date: Jan 2008
Location: Dweller

Posts: 4,398
iTrader: (0)

Quote:
Originally Posted by dcstep View Post
I'll be using 30-series, 18" tires for my autocross set up next year. I'll be going to a 10" to 10.5" rear wheel to allow as much tire as possible back there, to gain acceleration, since AX is mostly run in 2d gear and I now spin my 19" wheel/tire set at will anywhere on the course. The low profile will give both a wider contact patch and stiffer sidewall. The front tires will also be 30-series and about 20mm narrower than the backs, to maintain balance.

The added advantage of 18", 30-series tires will be that the final drive ratio will be slightly higher numerically, improving mid-gear acceleration.

For street, I'll be staying with the 19" factory option, forged wheels in summer and 18" factory wheels, with snow tires for winter. I think these are the best compromise of ride and handling, where my AX setting is aimed at acceleration and handling with no concern for ride.

Dave
Sorry, how do you figure the 18 x 30 tires will give you a lower profile side wall?
__________________
==================================================
KonigsTiger is offline  
0
Reply With Quote
      07-22-2009, 01:28 PM   #16
dcstep
Brigadier General
 
Drives: '09 Cpe Silverstone FR 6MT
Join Date: Nov 2008
Location: Colorado

Posts: 4,882
iTrader: (0)

Garage List
2009 M3  [4.00]
Quote:
Originally Posted by BMW-M-Mexico View Post
Sorry, how do you figure the 18 x 30 tires will give you a lower profile side wall?
30-series vs. stock at 40-series, equals lower profile. Maybe I don't get your drift.

Dave
__________________
dcstep is offline   United_States
0
Reply With Quote
      07-22-2009, 03:01 PM   #17
elp_jc
Brigadier General
 
Drives: .
Join Date: May 2008
Location: .

Posts: 4,910
iTrader: (0)

There's always a point of diminishing returns on everything. On wheel size, seems like it's between 18s and 19s, depending on track, as previously said; no one tire/wheel combo is best for everything.
By the way, stock 19s are lighter than 18s because they're forged, but forged 18s would be lighter than forged 19s in same design, but a 5-spoke design would be even lighter. Then you have the tire width, aspect ratio, and wheel width to mess with .
elp_jc is offline   United_States
0
Reply With Quote
      07-22-2009, 03:14 PM   #18
askiles
Major
 
askiles's Avatar
 
Drives: 2008 M3 Sedan - Alpine White
Join Date: Apr 2009
Location: Phoenix, AZ

Posts: 1,164
iTrader: (2)

Quote:
Originally Posted by dcstep View Post
30-series vs. stock at 40-series, equals lower profile. Maybe I don't get your drift.

Dave
Depends on the width obviously.

-Andy
__________________
2008 M3 Sedan- Alpine White
askiles is offline  
0
Reply With Quote
      07-22-2009, 03:53 PM   #19
dcstep
Brigadier General
 
Drives: '09 Cpe Silverstone FR 6MT
Join Date: Nov 2008
Location: Colorado

Posts: 4,882
iTrader: (0)

Garage List
2009 M3  [4.00]
Quote:
Originally Posted by askiles View Post
Depends on the width obviously.
Duh, really???

Dave
__________________
dcstep is offline   United_States
0
Reply With Quote
      07-22-2009, 05:07 PM   #20
wea
Private
 
Drives: 2012 Porsche Cayman R
Join Date: Jan 2009
Location: Austin, TX

Posts: 74
iTrader: (2)

Quote:
Originally Posted by PunjabiM3 View Post
F1 cars run tires with HUGE sidewalls...I wonder why...
This is due to Formula 1 Technical Regulations on maximum brake size which is limited to a diameter of 10.9" or 278mm and to limit the cooling potential they limited the rim size. The thinking is that 13" rims (332mm max) would limit ability to cool the brakes because of the limited space. The high side wall is a consequence of the small rims.

FYI, F1 cars were braking 4.5G going into turn 10 at the German GP, so I guess that is limited.

2009 Formula 1 Technical Regulations

Cheers
__________________
Favorite Quote on Supercars: "They are designed to melt ice caps, kill the poor, poison the water table, destroy the ozone layer, decimate indigenous wildlife, recapture the Falkland islands, and turn the entire third world into a huge uninhabitable desert... but only after they nicked all the oil." Jeremy Clarkson from Top Gear 05x02 @ 48:55.
wea is offline  
0
Reply With Quote
      07-22-2009, 05:08 PM   #21
ben@tirerack
M3Post Supporting Vendor
 
Drives: 740i
Join Date: Mar 2008
Location: South Bend, IN

Posts: 850
iTrader: (0)

Quote:
Originally Posted by elp_jc View Post
There's always a point of diminishing returns on everything. On wheel size, seems like it's between 18s and 19s, depending on track, as previously said; no one tire/wheel combo is best for everything.
By the way, stock 19s are lighter than 18s because they're forged, but forged 18s would be lighter than forged 19s in same design, but a 5-spoke design would be even lighter. Then you have the tire width, aspect ratio, and wheel width to mess with .
Very good point regarding the point of diminishing returns. I read a test (way back in the early 90's I think) which compared results plus-sizing from a (then common) 15" wheel to +1, +2, and +3 sizing. The +1 was a little quicker around the track, the +2 was quicker yet, but started to feel a little harsher ride, and the +3 was not any faster than the +2, but harder riding.

This was one test of one car by one magazine, but it illustrates the point. In general, a particular vehicle stops gaining performance at a particular wheel size (aside from vehicles with extreme mods that may have special parameters).

Generally, newer cars are engineered around bigger wheels. So tire sizes that used to be silly are now common. 18" wheels on an E36 were 'too big' for pure performance, but are now the smallest thing offered on the E9x.

A little bit of flex makes a tire more progessive, too much sidewall flex makes it sloppy in transition. So there is always an optimal mid point between too big and too small. Honestly I'm not yet sure if it's 18 or 19.
__________________
_______________________________________________



To credit the forum, click through one of the banners in my signature and the top of the page, or call me direct at 877.522.8473 ext 660.
Email:ben@tirerack.com
ben@tirerack is offline  
0
Reply With Quote
      07-22-2009, 10:41 PM   #22
stylinexpat
Captain
 
stylinexpat's Avatar
 
Drives:
Join Date: Aug 2008

Posts: 807
iTrader: (0)

Quote:
Originally Posted by ben@tirerack View Post
Very good point regarding the point of diminishing returns. I read a test (way back in the early 90's I think) which compared results plus-sizing from a (then common) 15" wheel to +1, +2, and +3 sizing. The +1 was a little quicker around the track, the +2 was quicker yet, but started to feel a little harsher ride, and the +3 was not any faster than the +2, but harder riding.

This was one test of one car by one magazine, but it illustrates the point. In general, a particular vehicle stops gaining performance at a particular wheel size (aside from vehicles with extreme mods that may have special parameters).

Generally, newer cars are engineered around bigger wheels. So tire sizes that used to be silly are now common. 18" wheels on an E36 were 'too big' for pure performance, but are now the smallest thing offered on the E9x.

A little bit of flex makes a tire more progessive, too much sidewall flex makes it sloppy in transition. So there is always an optimal mid point between too big and too small. Honestly I'm not yet sure if it's 18 or 19.

You can get them with 18" or 19" from the factory and an inch must make some sort of difference. Between size and weight I can't see them as pretty close if the weight savings were 5-7 lbs. per corner. If one went to a lightweight forged 18" wheel and saved 5-7 lbs. per corner I would be surprised to see no performance gains..
stylinexpat is offline  
0
Reply With Quote
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
Forum Jump


All times are GMT -5. The time now is 01:59 PM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
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