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 > Track / Autocross / Dragstrip / Driving Techniques
 
PYSPEED
Post Reply
 
Thread Tools Search this Thread
      05-24-2010, 04:53 PM   #1
MojorisinM3
Major
 
MojorisinM3's Avatar
 
Drives: 08 M6
Join Date: Apr 2005
Location: Nashville, TN

Posts: 1,043
iTrader: (0)

Track day tire pressure 18" stock tires?

Hi guys, my first track day tomorrow with my E90. What tire pressure is optimal? Its going to be 85 degrees here so the tires will be hot!
__________________
08 M6
MojorisinM3 is offline  
0
Reply With Quote
      05-24-2010, 06:33 PM   #2
MojorisinM3
Major
 
MojorisinM3's Avatar
 
Drives: 08 M6
Join Date: Apr 2005
Location: Nashville, TN

Posts: 1,043
iTrader: (0)

Quote:
Originally Posted by TrackRat View Post
The "optimal" pressure is TBD. A pyrometer is your friend if you're really interested in "optimal".

Typically you start 5-8 psi higher than BMW calls for an adjust according to the tires performance, your skills, the track, etc.

P.S. Have fun and stay hydrated with the hot temps!
thanks for the response. so 5 psi hgher? i would think keep standard as the tires heat up, no? so if its 35 then start with 40? what happens if they get up over 40, reduce heat betweens runs?
__________________
08 M6
MojorisinM3 is offline  
0
Reply With Quote
      05-27-2010, 09:45 AM   #3
elh0102
Captain
 
Drives: E92 M3
Join Date: Apr 2010
Location: USA

Posts: 704
iTrader: (0)

Assuming the OE street tires, you are probably going to find that something in the 38-42 range, hot, will be your sweet spot, but you will have to experiment. And you are right, start a few pounds below your target range, and check the pressures immediately upon coming off track. Just noticed this thread is a few days old, how did it turn out?
elh0102 is offline  
0
Reply With Quote
      05-27-2010, 12:19 PM   #4
Jaypod
Brigadier General
 
Jaypod's Avatar
 
Drives: Frozen Silver M3, AM V8V
Join Date: Nov 2008
Location: Toronto

Posts: 4,905
iTrader: (7)

Quote:
Originally Posted by TrackRat View Post
Over 40 psi has no particular significance.
Actually it does - you need to be aware of what the max psi rating is for your tire. I would not recommend starting your pressure at 40 psi for the OEM PS2's for example which is max 50 psi - I usually started mine around 31-33 and after a session they generally get to around 40 and seemed to perform fine although the get a little greasy after 4 or 5 laps. I have seen tire temps start at 31-33 and go as high as 45psi which in my opinion is too high for this tire and this car which leads to premature wear and lots of oversteer (although that can be lots of fun )
Jaypod is offline   No_Country
0
Reply With Quote
      05-27-2010, 02:14 PM   #5
igom3
Captain
 
Drives: 2002 E46M3 2013 535i
Join Date: Mar 2009
Location: San Diego

Posts: 762
iTrader: (1)

Garage List
2013 535I  [0.00]
2002 E46 M3  [0.00]
Quote:
Originally Posted by Jaypod View Post
Actually it does - you need to be aware of what the max psi rating is for your tire. I would not recommend starting your pressure at 40 psi for the OEM PS2's for example which is max 50 psi - I usually started mine around 31-33 and after a session they generally get to around 40 and seemed to perform fine although the get a little greasy after 4 or 5 laps. I have seen tire temps start at 31-33 and go as high as 45psi which in my opinion is too high for this tire and this car which leads to premature wear and lots of oversteer (although that can be lots of fun )
Agree
igom3 is offline  
0
Reply With Quote
      05-27-2010, 02:17 PM   #6
igom3
Captain
 
Drives: 2002 E46M3 2013 535i
Join Date: Mar 2009
Location: San Diego

Posts: 762
iTrader: (1)

Garage List
2013 535I  [0.00]
2002 E46 M3  [0.00]
I run my RA1 40-42 psi hot.
igom3 is offline  
0
Reply With Quote
      05-27-2010, 03:02 PM   #7
Jaypod
Brigadier General
 
Jaypod's Avatar
 
Drives: Frozen Silver M3, AM V8V
Join Date: Nov 2008
Location: Toronto

Posts: 4,905
iTrader: (7)

Quote:
Originally Posted by TrackRat View Post
The max tire pressure listed on the sidewall is for DOT purposes for a fully loaded vehicle running down the hwy. It's typically 50 psi or higher on hi-perf radial pass car tires. This pressure rating has nothing to do with the operating pressure that the tire can use. You should use the pressure that gives the best performance which is typically 5-8 psi higher cold than the car maker suggests for street use but it varies and that is why a tire pyrometer is so valuable. Each tire, driver, track and vehicle are different so you adjust the tire for the best performance. If you're starting with 33 psi cold and getting to 45 psi you're probably over driving/heating the tires.

FWIW - Many FWD appliactions run well above 55 psi pressures hot without any issues. As Hoosier and BFG state, this is much better than running under inflated tires and damaging them.

Excessive heat from under-inflation or abuse can cause serious tire failures as seen in the link below.

http://www.e90post.com/forums/showthread.php?t=390776
Umm - okay - were not talking about GTI's here. Most M3 drivers that I know that track their cars generally start their tires at the psi range I stated and go for 40ish hot. And that seems to work.

I will be sure to tell the guy that got his tires to 45 that he is over driving his car He has tons of experience racing and probably the quickest driver I know. I am pretty sure he knows what he is doing.....

Not sure what you drive, but if you want to start your pressure high - that's your prerogative. Glad it works for you, but I hope you don't blow a tire.
Jaypod is offline   No_Country
0
Reply With Quote
      05-27-2010, 03:38 PM   #8
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3 SQ5
Join Date: Apr 2007
Location: Toronto

Posts: 6,601
iTrader: (0)

I generally start at about 32-34 psi and aim for 40-42 psi when the tires are hot.I have seen pressure increases of up to 15 lbs from the crappy R888's when I had poor rear grip.Even at the low tire pressures cold tire roll over has not been much of an issue.
Gearhead999s is offline  
0
Reply With Quote
      05-27-2010, 03:42 PM   #9
Jaypod
Brigadier General
 
Jaypod's Avatar
 
Drives: Frozen Silver M3, AM V8V
Join Date: Nov 2008
Location: Toronto

Posts: 4,905
iTrader: (7)

Quote:
Originally Posted by TrackRat View Post
All of the tire companies tell you to use more pressure for the track than street pressures and to start high and adjust as necessary, due to the increased loads placed on a tire on track. A tire's load capacity is a direct function of tire pressure.

You can do whatever makes you happy. People ignore good technical information all the time based on perception instead of actual objective scientific testing like tire engineers conduct. It makes absolutely no difference to me what pressures you run. I just try to provide technically accurate information for those who want it. What people do with it is completely their decision.

BTW, a tire doesn't know or care what vehicle it is on. All it cares about is the loads placed on it. You can damage a tire on any vehicle with improper pressures or driving style.
No kidding - but weight and the type of car their mounted to is a very important factor - one which you have ignored. Not all tires perform well on all cars at the track.

I know what you are trying to say. I know many say increasing tire pressures by aprox. 10% above the cars specs. Again not all cars are going to have the same spec for the same tire. Unfortunately Theory and Reality are not often the same. I am not suggesting the info you have stated is not valid or accurate - just stating doesn't work in all instances and we are talking about M3's and their not exactly light. The driver's style is also going to have an impact as well - and that has nothing to do with over driving.
Jaypod is offline   No_Country
0
Reply With Quote
      05-27-2010, 06:02 PM   #10
ShadeD1
First Lieutenant
 
Drives: 2010 Jerez Black E92 DCT
Join Date: Feb 2010
Location: Houston, TX

Posts: 319
iTrader: (0)

I run the oem continentals at 39 hot.
ShadeD1 is offline   United_States
0
Reply With Quote
      05-27-2010, 08:19 PM   #11
drivendriver
Second Lieutenant
 
drivendriver's Avatar
 
Drives: 2010 E83 X3
Join Date: Apr 2009
Location: Alexandria, VA

Posts: 269
iTrader: (0)

Quote:
Originally Posted by Jaypod View Post
Actually it does - you need to be aware of what the max psi rating is for your tire. I would not recommend starting your pressure at 40 psi for the OEM PS2's for example which is max 50 psi - I usually started mine around 31-33 and after a session they generally get to around 40 and seemed to perform fine although the get a little greasy after 4 or 5 laps. I have seen tire temps start at 31-33 and go as high as 45psi which in my opinion is too high for this tire and this car which leads to premature wear and lots of oversteer (although that can be lots of fun )
That's my experience too. I usually start at 30-32 or 31-33 (cold). On a very hot track, I have indeed seen 10+ psi differences between hot and cold, and I agree that the PS2's don't work very well above 40 hot.

I don't think you can avoid the "greasiness" on a hot day. It's just a limitation of the design. If the air temp is 85, then it's likely to happen.
__________________
drivendriver is offline  
0
Reply With Quote
      05-28-2010, 07:19 AM   #12
Jaypod
Brigadier General
 
Jaypod's Avatar
 
Drives: Frozen Silver M3, AM V8V
Join Date: Nov 2008
Location: Toronto

Posts: 4,905
iTrader: (7)

Quote:
Originally Posted by TrackRat View Post
That's why I tell people to run the tire pressures that make them happy...

I run the tire pressure that make my tires happy and then I'm happy.

I'm not ignoring the vehicle or driver. The tire simply doesn't care what the vehicle is or who is driving. All the tire cares about is the forces imposed on it. A basic vehicle dynamics primer such as Herb Adams' "Chassis Engineering", Fred Puhn's "How to make you car handle", etc. may help people btter understand the relationship between tire loads, pressures and performance?

The tire engineers that develop the tire pressure recommendations do so by actual instrumented track testing with professional drivers. They don't just pull numbers out of the air. You will notice that the heavier the vehicle the higher the recommended tire pressure. That is because the load capacity of the tire increases with pressure. So if you're running a heavier car you want higher tire pressures to handle the loads. That is why Hoosier, BFG and other tire companies provide nice technical info. on getting the most from your performance tires for track use. Accurate testing and a pyrometer give you the answers to what is the optimal tire pressure, camber settings, etc. Without careful testing and data gathering you're just guessing.
If you cant recognize that there is a direct correlation here - enjoy your theory and marketing info and have fun at the track. Many of us in the M3 track section of the forum like to feedback on real life instances as that's what really matters. Car specific information not just marketing and text book info. The OP asked about tracking his E90 M3 not <insert other car here>. For some reason you fail to see or comprehend this.

But thanks for the info - I am sure some find it interesting - just doesn't answer the OP's question or seem to be the experience of the other track goers here.
Jaypod is offline   No_Country
0
Reply With Quote
      05-28-2010, 11:27 AM   #13
Jaypod
Brigadier General
 
Jaypod's Avatar
 
Drives: Frozen Silver M3, AM V8V
Join Date: Nov 2008
Location: Toronto

Posts: 4,905
iTrader: (7)

Quote:
Originally Posted by TrackRat View Post
Jaypod-

You seem to be taking the comments personally and there is no need to. If you don't understand the point that the tire doesn't care what car it's mounted on maybe you should read a vehicle dynamics reference and get up to speed on the friction circle and tire loads. The laws of physics don't change by car. A tire does not know or care what car it is on. All it cares about is the loads it must deal with. The loads are different for different cars, tires, tracks, etc. This isn't theory it's reality. That is why you test to determine what works best.

No one can tell the OP what the "optimal" tire pressure is for his tires as it varies by tire, car, track, ambient temp, etc. All anyone can do is give the OP a recommended starting point. From there he should test to determine what works best for him. In my track cars I run four different tire pressures because that is what the tires want for a given track configuration, tire loads, weight distribution, etc. the tire makers give your recommended tire pressures based on real world testing. They give you a safe range to start in for testing.
I am actually not taking anything personally - get over yourself - sounds like you are though. I am not the one looking for advice and could care less about yours. (sorry if that hurts your feelings) I don't know you and could care less about you or if you like what I have to post. My pet peeve is watching someone post info on a forum to someone who is looking for some advice. OP mentions this is his first time tracking his M3 - best advice is going to be to give real life examples are here from people who actually track an M3, not just regurgitate info they have read or plagiarize from a website. If this is his first day tracking the car, reality is he may not even have enough track time to find optimal for the track conditions, but at least he will be further along and better prepared with the info others have offered.

I find that there are a lot of very experienced forum members which offer great advice based on real life experience on this forum. Sorry your not one of them. (and for the record, I don't care if my opinion or advice matters to other people, maybe that's the difference between you and I) It certainly doesnt take much to get you on the defensive - quite fun actually!
Jaypod is offline   No_Country
0
Reply With Quote
      05-28-2010, 07:43 PM   #14
V1.47fan
Captain
 
V1.47fan's Avatar
 
Drives: Bay M Vee
Join Date: Apr 2008
Location: NATIONWIDE

Posts: 976
iTrader: (0)

Quote:
Originally Posted by TrackRat View Post
The max tire pressure listed on the sidewall is for DOT purposes for a fully loaded vehicle running down the hwy. It's typically 50 psi or higher on hi-perf radial pass car tires. This pressure rating has nothing to do with the operating pressure that the tire can use. You should use the pressure that gives the best performance which is typically 5-8 psi higher cold than the car maker suggests for street use but it varies and that is why a tire pyrometer is so valuable. Each tire, driver, track and vehicle are different so you adjust the tire for the best performance. If you're starting with 33 psi cold and getting to 45 psi you're probably over driving/heating the tires.

FWIW - Many FWD appliactions run well above 55 psi pressures hot without any issues. As Hoosier and BFG state, this is much better than running under inflated tires and damaging them.

Excessive heat from under-inflation or abuse can cause serious tire failures as seen in the link below.

http://www.e90post.com/forums/showthread.php?t=390776
Agreed,
I usually start at 40psi front 36psi rear,anything less than 35psi hot I get serious front tires rollover then again autocross is a bit more extreme than road racing.hahaha
I wouldn't start off at 30-31psi for such a heavy car...
__________________
V1.47fan is offline   United_States
0
Reply With Quote
      05-28-2010, 08:33 PM   #15
revster
Private
 
Drives: 2008 e90 M3
Join Date: Jun 2009
Location: Oakland, CA

Posts: 70
iTrader: (0)

Ran Thunderhill last fall, it was easily over 92 deg F ambient. Started at 40 psi hot on PS2 stock 18s, got them down to 38 psi hot after couple sessions and stuck with that. Did not get significant shoulder/sidewall wear, so I probably could have gone a little lower.

Ran Laguna Seca this past Wed, cloudy and passing light showers. Started at 40 cold and pretty much left it there as I didn't run very hard in my sessions and was not gonna chance testing the limits in varying cold/wet conditions.

Whatever temps you decide at, always look at your sidewalls to gauge how much deformation you are getting and adjust (small increments!) as necessary.
__________________
revster :: 08 e90 M3 jerez/black/carbon
revster is offline  
0
Reply With Quote
      05-28-2010, 11:19 PM   #16
Hellride
Private
 
Hellride's Avatar
 
Drives: 2008 E92 M3 Jet Black
Join Date: Oct 2008
Location: Southern California

Posts: 90
iTrader: (0)

I target 40 hot back at the paddocks. Depending on the tire, the weather, the track - I may be estimating between a 5 and 10psi gain after a session. I've run both BFG-R1's and NT-01's and they both seem to get real greasy north 40, especially the R1's.

I've started my day as low as 28. But starting that cold - you have to warm them up (lap or 2 or more) before any fast laps. Then monitor the sidewall or use shoe polish. Unless you have a good pyrometer, not sure it's too useful (yet).

Having said this, at your first event starting higher - even as high a 5psi above MFG rec could be a good thing. How'd it go?
__________________
08 E92 DCT31.1 | JTBLK/BLK/CARBON LEATHER | CF ROOF | TP | PP | 18 | MEDIUM CERAMIC TINT | HARDWIRE V1
Hellride is offline   United_States
0
Reply With Quote
      05-29-2010, 06:51 AM   #17
Jaypod
Brigadier General
 
Jaypod's Avatar
 
Drives: Frozen Silver M3, AM V8V
Join Date: Nov 2008
Location: Toronto

Posts: 4,905
iTrader: (7)

Quote:
Originally Posted by TrackRat View Post
Jaypod-

You have a bad attitude that does not serve any useful purpose.

Stating accurate info. with references is not defensive at all it's enlightening for those who want to learn. I tried to explain to you technical information which you obvious don't understand and then you take it personally and post inappropriate barbs because you don't understanding the physics involved and thus have a closed mind on the subject.

It's acceptable to respectifully disagree with someone without the cheap shots that are a technically and socially ignorant retort.
Ah yes, I have a bad attitude - well if wanting to see a fellow M3 owner/enthusiast gets some useful info for the first day tracking their M3 so they can go out and not worry and enjoy themselves give me a bad attitude - Guilty as charged and I can live with that.

Perhaps you should go back and read your posts. Just because I suggested to not starting your pressures above the OEM pressures (which is my opinion, and apparently the opinion of others that have replied to this thread as well) for an M3 you get your knickers in a twist and get defensive and suggest that because someone is getting 10psi or so gain in their tires they are over diving their car. I have made no mention of your driving ability or lack there of nor have I suggested that the generic info you have posted is useless. I (and others) who have tracked their M3's have given our experience and recommendation that seems to work for this car.

Your babel about operating temperatures etc is all fun and nice, but we are talking about M3's not FWD cars which you seem to have an fascination with.

Perhaps you can relate to us your M3 specific tracking experience and the pressures and tires and set up of your car. I guarantee you that members here with find that info much more useful. You seem to like to hear yourself speak or see your words on a screen so make some thread and knock yourself out. Sorry I am not hanging off your every word but I can go to any tire manufacturing website or track site and get the generic info you provided over and over and over again.

Please enlighten us oh wise one. Sorry for raining on your parade......

Bad attitude signing out! (someone please remind me where the ignore user option is for this site! )

PS - read through the threads, you will find that there is a lot of very experienced racers/lappers in this forum who can provide a wealth of knowledge that is very useful for our cars (I am in no way suggesting that I am one of them). In my experience learning from those that can and do, is much more valuable than any text book or marketing material. You never know you might learn something!
Jaypod is offline   No_Country
0
Reply With Quote
      05-29-2010, 10:38 PM   #18
V1.47fan
Captain
 
V1.47fan's Avatar
 
Drives: Bay M Vee
Join Date: Apr 2008
Location: NATIONWIDE

Posts: 976
iTrader: (0)

Hahaha it's hard to get two M3 owners to agree on anything. Then again there are a bunch of threads on ruined front PS2's.

If you start at 28psi before the tires get hot and overdrive the car,you can get some serious sidewall flex that might lead to excessive tire wear on the outside shoulder.

So it might be better to start close to the target psi and go down as required.
__________________
V1.47fan is offline   United_States
0
Reply With Quote
      06-04-2010, 07:34 AM   #19
bigjae1976
Takes threads off topic...daily
 
bigjae1976's Avatar
 
Drives: 11 E90 M3 Individual
Join Date: Mar 2006
Location: Milwaukee, WI

Posts: 5,077
iTrader: (11)

Garage List
2004 BMW M3  [4.50]
2011 BMW E90 M3  [5.00]
2013 BMW 328i  [5.00]
There is a great article on tire pressures in Roundel...I think it is the one with the review on the new 5er...which is a great looking car BTW!
__________________


Sponsored by Momentum BMW #593...We Bleed BMW BLUE!
bigjae1976 is offline  
0
Reply With Quote
      06-04-2010, 09:21 PM   #20
adc
Brigadier General
 
Drives: 2009 E90 M3 ED
Join Date: Sep 2006
Location: MD/DC

Posts: 4,033
iTrader: (6)

Quote:
Originally Posted by bigjae1976 View Post
There is a great article on tire pressures in Roundel...I think it is the one with the review on the new 5er...which is a great looking car BTW!
+1, read that and actually applied it at the track.


Tracking at Summit Point Main, 70-80 degree day which started rainy and ended up warm & sunny. I started with +3psi over the manufacturer recommended pressures and it worked pretty well.

I probably should have increased by 1 or even 2 PSI, there was just a hint of rollover scrub on the top of the sidewall.
__________________

2009 E90 M3 ED
2014 X1 28i
2000 Boxster
adc is offline  
0
Reply With Quote
      07-16-2010, 06:24 PM   #21
LvnLrg213
Private First Class
 
Drives: 2013 F10 M5; 2013 X5M
Join Date: Oct 2007
Location: Coral Gables, Florida

Posts: 125
iTrader: (0)

Quote:
Originally Posted by bigjae1976 View Post
There is a great article on tire pressures in Roundel...I think it is the one with the review on the new 5er...which is a great looking car BTW!
Link to the article??
LvnLrg213 is offline  
0
Reply With Quote
      07-16-2010, 08:22 PM   #22
bigjae1976
Takes threads off topic...daily
 
bigjae1976's Avatar
 
Drives: 11 E90 M3 Individual
Join Date: Mar 2006
Location: Milwaukee, WI

Posts: 5,077
iTrader: (11)

Garage List
2004 BMW M3  [4.50]
2011 BMW E90 M3  [5.00]
2013 BMW 328i  [5.00]
Well, I couldn't find window chalk here in Korea so I used whiteout. Works, just makes a more permanent white mark on your tires.

So cold PSI was 38, hot was 46L/45R PSI. Max load on my tires is 51.

So I guess I would try to dial in a little more camber first? If I increase tire pressure by 1-2 PSI, I fear that I will be getting close to the max PSI of my tires.

Quote:
Originally Posted by LvnLrg213 View Post
Link to the article??
April 2010 issue of Roundel.

Try this link: http://roundel.imirus.com/Mpowered/i...issue=7&page=1

I think this will only work if you have a BMWCCA membership. I will try to print and scan from work.
__________________


Sponsored by Momentum BMW #593...We Bleed BMW BLUE!

Last edited by bigjae1976; 07-16-2010 at 08:27 PM.
bigjae1976 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 04:53 AM.




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