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      09-01-2013, 07:32 PM   #67
JimD
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OK, here's some more references recommending higher pressure:

http://www.tirerack.com/tires/tirete....jsp?techid=58

This recommends higher pressure on the track than on the street:

http://www.motoiq.com/MagazineArticl...-Pressure.aspx

This one recommends setting pressure by temperature which seems like the right thing to do. But I lack the equipment. It also suggests setting cold pressure and only fine tuning hot. I agree completely with that, the cooling time affects the hot temperature making adjustments much more difficult.

http://www.trackpedia.com/wiki/Tire_pressure

This one recommends the same sort of testing I did and illustrates it. It doesn't really recommend high pressures although it says he runs 38-40 in front:

http://racingready.com/2010/05/27/ti...s-tuning-tips/

I will know better what Michelin PSS want after I actually get to use them in an autocross. But I will start at 40 psi and not be surprised if I have to go up. But maybe I will be surprised and have to go down. We'll see. I will probably mark them so I know if I am on the tread or the shoulder of the tire.

I will also point out what I said in the first post I made, a lot of the one lap of America cars were running Michelin tires which seemed to be PSS. Surely one lap cars are viewed as having pretty extreme duty. They were also on a M6 I saw at the dealership. I don't think BMW would pretty tires prone to chunking on a M6.
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Last edited by JimD; 09-01-2013 at 07:37 PM.
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      09-01-2013, 08:38 PM   #68
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Jim, not sure why you're still arguing this?
Did you actually read your own "references"?

1. http://www.tirerack.com/tires/tirete....jsp?techid=58

Cold starting points:
"Front Engine/Rear Drive
Front 35-45 psi
Rear 30-40 psi"

Sounds about right. The RS-3 start about 32psi cold to get them to around 38/40 hot.
Tirerack doesn't mention vehicle weight though, which as I said is a serious consideration.

2. http://www.motoiq.com/MagazineArticl...-Pressure.aspx

"The baseline hot tire pressure for most cars is usually from 38 to 45 PSI."

"So if it's an 80 degree day and you'd like your tires to be at 38 PSI hot, set the tires at 30 PSI cold."

3. http://www.trackpedia.com/wiki/Tire_pressure

"Somewhere within the 30-40 psig range is likely for most cars"

"the typical pressures you run on the street are going to be too high for the race track. During normal street driving, tire pressures will increase over the recommended factory "cold" settings about 2-4 psig. During racing, a cold tire pressure setting will increase anywhere from 6 to 10 psig. Tire pressures must be lowered from their usual street settings before going onto the track. "

4. http://racingready.com/2010/05/27/ti...s-tuning-tips/

Doesn't say if hot or cold (I'd assume hot), but:
"My rear tires at that pressure couldn’t get traction AT ALL! I ended up with the rear pressure at 32-33 which gave me the balance I was looking for."

Quote:
I will know better what Michelin PSS want after I actually get to use them in an autocross. But I will start at 40 psi and not be surprised if I have to go up. But maybe I will be surprised and have to go down.
*Maybe* on a 128i, but no way on the 135i... Your car will handle like on ice skates. Good luck with that!
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      09-02-2013, 06:34 PM   #69
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Quote:
Originally Posted by JimD View Post
I will know better what Michelin PSS want after I actually get to use them in an autocross. But I will start at 40 psi and not be surprised if I have to go up. But maybe I will be surprised and have to go down. We'll see. I will probably mark them so I know if I am on the tread or the shoulder of the tire.

I will also point out what I said in the first post I made, a lot of the one lap of America cars were running Michelin tires which seemed to be PSS. Surely one lap cars are viewed as having pretty extreme duty. They were also on a M6 I saw at the dealership. I don't think BMW would pretty tires prone to chunking on a M6.
The "shoulder" is still the tread, and should be driven on the shoulder. This is not to be mistaken by the sidewall, which I think you're mixing up the terms.

As well, to comment on your first post regarding the BMW Performance Center, they throw whatever tires they get for free. This is directly out of the mouth as Hans, the same guy that broke the World Record for the longest Drift.

Quote:
Originally Posted by int2str View Post
Jim, not sure why you're still arguing this?
Did you actually read your own "references"?

1. http://www.tirerack.com/tires/tirete....jsp?techid=58

Cold starting points:
"Front Engine/Rear Drive
Front 35-45 psi
Rear 30-40 psi"

Sounds about right. The RS-3 start about 32psi cold to get them to around 38/40 hot.
Tirerack doesn't mention vehicle weight though, which as I said is a serious consideration.

2. http://www.motoiq.com/MagazineArticl...-Pressure.aspx

"The baseline hot tire pressure for most cars is usually from 38 to 45 PSI."

"So if it's an 80 degree day and you'd like your tires to be at 38 PSI hot, set the tires at 30 PSI cold."

3. http://www.trackpedia.com/wiki/Tire_pressure

"Somewhere within the 30-40 psig range is likely for most cars"

"the typical pressures you run on the street are going to be too high for the race track. During normal street driving, tire pressures will increase over the recommended factory "cold" settings about 2-4 psig. During racing, a cold tire pressure setting will increase anywhere from 6 to 10 psig. Tire pressures must be lowered from their usual street settings before going onto the track. "

4. http://racingready.com/2010/05/27/ti...s-tuning-tips/

Doesn't say if hot or cold (I'd assume hot), but:
"My rear tires at that pressure couldn’t get traction AT ALL! I ended up with the rear pressure at 32-33 which gave me the balance I was looking for."



*Maybe* on a 128i, but no way on the 135i... Your car will handle like on ice skates. Good luck with that!
40 PSI in the rear is just asking to light tires up. I have hard with traction on 265s, and 27 PSI hot for autocross.

At least OP gets what I'm trying to explain. It is one thing to read an article, another is to drive your car, play with pressures, and tune them to maximize the performance of the tire without compromising the tires life.

Typical rule of thumb is 8 PSI gain for autocross. I start at 34 front and 32 rear cold pressures at Mid-Ohio, and ended at 38 PSI by the time I get to paddock, which means I probably cooled down a pound or so and can start at lower pressures.
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      09-02-2013, 07:40 PM   #70
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Kgolf31,

Huh? The first reference, even by your quote recommends cold pressures higher than BMW recommends, including the 40 psi I plan (although that is close or at the top of the range). The second reference contains the phrase " When driving on a racetrack you should run a higher tire pressure than you would normally run on the street. " I'm not sure what car you are referring to but for a 1 series, the pressures you are talking about are also a little higher than the sticker in my car so maybe you agree. The third reference does talk about starting below stock tire pressure when testing tires with a temperature probe. But I don't see anything that pretends to know where you will end up. Your pick of quote for the last reference is OK but deceptive since he also says the best front tire pressure for his tires and car was 38-40. Doesn't mean a lot about what is best for PSSs.

So you try and pick a few words from each reference that supports your position? Or say tire rack does when they clearly don't? And you seem to run above stock pressures but argue it can't be the OP's issue if he ran stock pressure and damaged his tires? Huh?

Do you think everybody is stupid or what? The simple fact is that the OP may or may not have run the wrong tire pressure for his tire and car but the fact that the tires were damaged is plenty of reason to try something different. The range of suggested pressures do go down to stock or a little below but also go much above stock pressures.

The other obvious fact is that Michelin PSS tires are great tires. Use Google a little and you can find tests on great cars on a race track with great results. You can run whatever you want but PSS tires are plenty suitable for track use. I am going to take the OP's results as an indication they like more pressure than some. With a soft sidewall, that would also be my first guess. But I will test and let that and the feel of the car tell me where to go from there.
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      09-02-2013, 07:53 PM   #71
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there's no one size fits all solution. as has been said earlier there are many variables to consider and weight is a big one among others. tire pressure is the last track side fine tuning option available to achieve the balance desired. there's definitely a sweet spot to be discovered somewhere between under and over inflation. generally speaking the heavier the car the more pressure you will need for maximum traction so it's not surprising the pro driving the FRS on such low pressures. personally I got best handling balance for my driving style on my R-comps around 38-40 hot. I would usually start around 6-8 psi lower from cold to get there plus I would shoot for a +1 rear pressure bias for a perfect neutral handling balance taking into account my total alignment specs and general handling characteristic.

PS. PSS's are not track tires and should not be mistaken for one
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      09-02-2013, 07:54 PM   #72
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Quote:
Originally Posted by JimD View Post
Kgolf31,

Huh? The first reference, even by your quote recommends cold pressures higher than BMW recommends, including the 40 psi I plan (although that is close or at the top of the range). The second reference contains the phrase " When driving on a racetrack you should run a higher tire pressure than you would normally run on the street. " I'm not sure what car you are referring to but for a 1 series, the pressures you are talking about are also a little higher than the sticker in my car so maybe you agree. The third reference does talk about starting below stock tire pressure when testing tires with a temperature probe. But I don't see anything that pretends to know where you will end up. Your pick of quote for the last reference is OK but deceptive since he also says the best front tire pressure for his tires and car was 38-40. Doesn't mean a lot about what is best for PSSs.

So you try and pick a few words from each reference that supports your position? Or say tire rack does when they clearly don't? And you seem to run above stock pressures but argue it can't be the OP's issue if he ran stock pressure and damaged his tires? Huh?

Do you think everybody is stupid or what? The simple fact is that the OP may or may not have run the wrong tire pressure for his tire and car but the fact that the tires were damaged is plenty of reason to try something different. The range of suggested pressures do go down to stock or a little below but also go much above stock pressures.

The other obvious fact is that Michelin PSS tires are great tires. Use Google a little and you can find tests on great cars on a race track with great results. You can run whatever you want but PSS tires are plenty suitable for track use. I am going to take the OP's results as an indication they like more pressure than some. With a soft sidewall, that would also be my first guess. But I will test and let that and the feel of the car tell me where to go from there.
Maybe you should see who is quoting you and quick attacking me. Even the OP is calling you out, and he is the one that went through the quotes. Not surprising that you're trying to prove me wrong when all I did was agree with those statements.

"Running a Higher Pressure" doesn't correlate to "I'm going to start at 40 PSI Cold WHAT SO EVER. I don't know how you're not getting this through your head.

Running a higher pressure is indeed running a higher pressure, but your cold starting pressures are pretty close, to if not the same as what the sticker shows. I run my tires lower than what my sticker shows, so that when I'm coming off the track they are INDEED running higher than what sticker shows. Start at 40 PSI, then I would love to hear you come off the track and tell everyone that the car can't corner, or grip, because you're coming at near maximum inflation rates of the tire.

In case you didn't realize, you can't come off the track, bleed air, and continue on. You're running the track hard for 20-30 minutes, so you need to account for that difference and pressure differential. I've made this fairly clear that my starting pressures for track were cold, and for autox are hot. And yes, my hot autox pressures are below my sticker ratings.

I don't want to use google, because it leads to false results from people that think they are good tires, when in reality they aren't the greatest out there. I'm going out on a limb, but people IMO buy these tires from false reviewers, and don't know any better and think the tires are awesome because they haven't driving on an actual high performance tires. And yes I said it, actual high performance tire because clearly....this tire cannot perform as such.

Instead, I'll use SCCA SOLO National Results for Street Tire Classes. You let me know when you find a car that was running Michelin tires

http://sololive.scca.com/STX.html

http://sololive.scca.com/STR.html

http://sololive.scca.com/STU.html

http://sololive.scca.com/STS.html

http://sololive.scca.com/STC.html

(Since you know so much about tires, I'm assuming you know about the Pixie Dust Tires and why cars are running Toyos within STS and STC. But if you don't I can explain)

http://sololive.scca.com/RT2.html

http://sololive.scca.com/RT4.html


I'd rather go with proven results, rather than some tests that 3rd party people have done. The consumers are the ones that make the ultimate choice, and clearly if it was a tire you thought it was...Michelin would be running at the top.
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      09-04-2013, 07:17 AM   #73
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Kgolf31,

I don't know how anybody would think that the sticker in your car refers to anything other than cold pressures. I also don't see how any reasonable person would see a reference to running higher pressures as referring to the heat up during track use. I think it is much more reasonable to look at these references as relating to higher cold pressure.

I will also remind you that I've already done this with positive results. I tested to see what pressure kept me off the sidewalls and ran that pressure (40psi cold). My times were pretty good for run flats. I can't see why running the same pressure on Michelins with their softer sidewall is a bad starting point. The articles put that pressure within the suggested range and my experience does the same. You want to read references to pressure in this range as referring to hot pressure. I am most certainly not talking about hot pressure. I doubt the articles are either unless that is specifically what they say.

I don't know why Michelins are not used by autocrossers but the PSS is a relatively new tire. I will remind you again that there were a lot of one lap cars with Michelins - I saw the sidewalls - and it is reasonable to think they were PSS. The duty in the one lap of America is more than at an autocross.

Jim
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      09-04-2013, 11:49 AM   #74
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Quote:
Originally Posted by JimD View Post
I don't know why Michelins are not used by autocrossers but the PSS is a relatively new tire. I will remind you again that there were a lot of one lap cars with Michelins - I saw the sidewalls - and it is reasonable to think they were PSS. The duty in the one lap of America is more than at an autocross.

Jim
BDG Rivals, as well as Dunlop ZIIs just came out this year, in fact the beginning of this year.

I'd call those newer than PSS.

As well, Do you want me to pull up NASA TT Cars that run street tires as well as LeMons cars? I doubt any of them are using PSS Tires.

I believe the blinders are put on, as you don't realize that the tire isn't good for hard driving duties. Now before you claim you know the one Lap of America cars were PSS and now you think it is reasonable to think they were PSS. So what is it? How do you not know they are PS2s?

Because you don't know, is hilarious because you can't back up any information.

Anyways, here is some reasonable data:

http://www.tirerack.com/features/mot...astresults.jsp

Yes, PSS was a tire used, but you can see the Rivals, ZIIs, and RS3s are all on that page as well.

Times that are good are subjective to the driver, unless you have video and/or results from events, 40 PSI could be slow...but felt good for you. The fact that I was running mid-30s on my RS3s and PAXing within top-20. Dropped them at and below 30s and now are running 4th in the past 3 events with 100+ drivers at each event should tell you something. Feel free to check out my videos, as I have proof.






Last edited by Kgolf31; 09-04-2013 at 02:27 PM.
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      09-04-2013, 01:31 PM   #75
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As Kgolf31 mentioned earlier, I think there is so much confusion with regarding the PSS because most of the "glowing" reviews about them are from people coming from non-performance tires or the stock run flats. Of course you're going to be blown away by its performance if you've never driven on anything in the same category that produces as much grip before.

Some people have success with them but Im willing to bet just about anything that the people who are thrilled with their performance on track and have never had a problem are newer/less experienced or simply aren't going very fast or pushing the car very hard (not aimed at anyone on this thread. It is just my personal belief.)

Jim- If you're happy with the PSS and you're pressure settings then more power to you! BUT it doesn't mean that it is the most correct thing to do. Have you tried lowering pressures down to the mid to high 30s HOT? If you need 40psi cold (close to 50 hot) to keep the tire off the sidewalls then you need more camber not more pressure. I don't care what tire is... If you're running hot pressures in the high 40s or low 50s you're choking the performance of the tire big time.

The PSS aren't used by (experienced) auto crossers or track day guys because they know better. As others have mentioned they are not meant for heavy competition. They will overheat very quickly which will lead to chunking if you keep pushing once its been overheated. They would make a descent track tire for rainy days though.

Yes, the PSS was used in tire rack's one lap but that doesn't mean anything. Most of the cars in the one lap (R35 GT-R for example) use tire sizes that most extreme performance summer tires don't offer. Additionally they are shorter "sprint" type events which don't put as much heat into the tires as say a 20 or 30 minute track session. Yes, they come standard on the M6 and a few other cars but that is also irrelevant. The PS2 suffered from the same things the PSS does and it came standard on those cars before the PSS was available. They are comfortable street tires that have pretty good cold grip and excellent wet grip and that is all.

Last edited by MMisencik157; 09-04-2013 at 10:05 PM.
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      09-04-2013, 04:37 PM   #76
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Okay teen girl squad, can we agree now?

Edit - you win the argument if you get the "teen girl squad" reference without googling it.
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      09-04-2013, 07:58 PM   #77
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IMO they aren't suitable for track. These are mine after only 12 laps, doing 3 hot laps at a time.
They were getting greasy very quickly and rolling over on the shoulder.

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      09-04-2013, 10:03 PM   #78
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Quote:
Originally Posted by Nugget View Post
IMO they aren't suitable for track. These are mine after only 12 laps, doing 3 hot laps at a time.
They were getting greasy very quickly and rolling over on the shoulder.

Thank you for posting. This is exactly what Im talking about.
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      09-04-2013, 10:11 PM   #79
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Quote:
Originally Posted by Nugget
IMO they aren't suitable for track. These are mine after only 12 laps, doing 3 hot laps at a time.
They were getting greasy very quickly and rolling over on the shoulder.

My PSS's chunked worse than that after a handful of autocrosses. Just fell apart!
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      09-04-2013, 10:27 PM   #80
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Quote:
Originally Posted by Bimmer-Bob View Post
My PSS's chunked worse than that after a handful of autocrosses. Just fell apart!
This was after only 4 lots of 3 laps. So about 12 minutes of total driving on nearly new tyres. I stopped before I ruined them and sold them. Great street tyres.
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      09-05-2013, 02:38 PM   #81
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Nugget and Bimmer-Bob, my key question is at what pressure? I am not suggesting you shouldn't have expected better performance from PSS tires, I am just trying to figure out if it is possible my experience will be different with different pressure.

For those of you who don't think one lap tells you anything, this is the 2012 schedule:

"With over 3,400 road miles and 16 more timed events scheduled in the seven days ahead of them, the teams began their One Lap of America journey driving to many of America's premier racetracks and motorsports country clubs for timed competition. This year's schedule included an autocross at Grisson Air Force Base, Bracket and ET drag racing at Alabama International Dragway (rained out), and road course competition at Talledaga Gran Prix Raceway, NOLA Motorsports Park, Daytona International Speedway (24 Hours of Daytona course), Carolina Motorsports Park, BMW Performance Center, Virginia International Raceway and Pittsburgh International Race Complex. Teams returned to Tire Rack for the final competitive event on Saturday morning, May 11th for a Dry Skid Pad Challenge followed by the now famous victory tire burnout celebration."

In that same competition, thanks to Kgolf, we know that 9 of 14 class winners of the wet skidpad competition were running PSS tires. If I counted right that is 9 competitions on the same set of PSS tires (no changes allowed by the rules). Most of the competitions more severe than an autocross. They also drove 3400 miles to reach all the competitions on the same set of tires.

So we have two different sets of experience, for sure, with at least 9 competitors in 2012 and probably more in 2013 in a pretty severe duty race having good experience with PSS tires. But we also know some of our fellow members got a lot less than they paid for out of the same PSS tires. That is what I am trying to reconcile. It seems like it is possible to get different experience out of PSS - but it is obviously possible to have adverse experience too. I'd like to know more about the aderse experience so I can avoid it.

For anybody wanting to disclaim the one lap example please click the link Kgolf provided. The cars running PSS tires include a e36 M3 and a new M6 and also at least one Porsche, a Vette, a Mustang, and a Camaro. A wide range of vehicles. Literally half the 14 class winners of the overall competition were on PSS tires including the overall winner and two bimmers. How can these be "bad tires" unsuitable for track duty?

Jim
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      09-05-2013, 03:21 PM   #82
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With the center chucking is telling me you have too much air in it. I track my pss and autocross them and the only time I seen wear like that was when it got over 40 psi. I found I was getting the best wear at 38 hot in the front and 36 rear it wore even with the little michelin man on the side. This is with stock m sport suspension and stock camber. I getting more wear on the outside but not pass the little michelin man. Never chunked a pss with pressures 36-38 hot. Only when I got at 41 psi.
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      09-05-2013, 03:26 PM   #83
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SCCA SCCA Solo Drivers that run street tires run Continental DWS Tires in the Wet. Does that mean they are good all-around tires for racing? No. They can channel water. Look at the tread on RS3s or ZIIs and you'll realize this quick. RS3s are not known for good wet weather. They SUCK. The fact that they do indeed suck, and cannot change tires, would make you think they need a more all-performing tire. This will make sense.

You also fail to see that you can get sponsorships to supply tires. Who knows if all of them who are supplied Hankook, Dunlop....etc aren't sponsored and supplied for free?

It appears, from the results, is that these are time attack events. Which means you are not pushing for 30 minutes. You set a hot lap, cool tires for a lap, and run another hot lap. I wouldn't call this the same abuse as a HPDE.

Highways is nothing, and shouldn't be accounted for. I've driven close to 10k on my RS3s, so what does that tell you? Nothing.


If we can look at exactly how long these tires are driven on during track we can further investigate. I have a feeling these are TT runs. As well, with full prep cars versus cars with no understeer, there can be easily more wear already.
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      09-05-2013, 09:28 PM   #84
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Quote:
Originally Posted by bimmer Don
With the center chucking is telling me you have too much air in it. I track my pss and autocross them and the only time I seen wear like that was when it got over 40 psi. I found I was getting the best wear at 38 hot in the front and 36 rear it wore even with the little michelin man on the side. This is with stock m sport suspension and stock camber. I getting more wear on the outside but not pass the little michelin man. Never chunked a pss with pressures 36-38 hot. Only when I got at 41 psi.
Absolutely I was running pressures that were too high, on the advice of others who warned me about excessive rollover due to the soft sidewall. I was starting around 37 cold, but wasn't bleeding off any air in between runs, so who knows how high they got (talking AX, not track). More recently I've been shooting for 38-40 hot, but the tires are already toast.
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      09-05-2013, 09:36 PM   #85
bimmer Don
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The tire not toast. That chunking not to bad it will clean up when they start to wear down.
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      09-05-2013, 09:40 PM   #86
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Oh next time you auto x spay down your pss with water after. 3rd run and every run after that. That's what I found success in keeping then from over heating at auto x
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      09-05-2013, 09:56 PM   #87
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Crazy thread. I've had good luck with MPSS so far. I agree with the post that says you need to watch the high pressures or risk chunking. No chunking on mine and starting cold pressure of 32. Also need to warm the tires up over a couple laps. After my next track event I expect that I will have consumed most of these tires. It will have been approx 6K miles plus 12 hours of hard track time.

As far as getting greasy you have to watch for that. If its happening then you are likely running a little high on pressure. At my last event this happened and my hot pressure was getting near 40. I pulled 4 out and was good again.

In the end the MPSS is NOT a track tire but is a pretty good track/street compromise. With proper precaution it will serve you well.
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      09-06-2013, 07:11 AM   #88
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Bimmer Bob, Bimmer Don, HeelToe and Kgolf,

Thanks. I think I better start lower on pressure and see where I need to go with my PSS tires.

With respect to Kgolf's question on how they run the One lap events, I only witnessed the BMW Performance Center. I've driven this course several times with cones set out to keep our speed down to about 70mph max in an autocross. I've also driven it at a 2 day M-school with a lot less cones and our maximum speed was about 100 mph (in the big sweeping turn). These guys were running the entire course so I would guess they were getting a little over 100 mph in spots (it is pretty tight). Maybe 110 or a little higher. We did not stay for the whole thing but I am pretty sure each car was running about 5 timed laps. I don't remember any warmups. That would be less than 10 minutes hard running. Tracks like VIR would be higher speed, I believe, but my guess is they run only a limited number of laps like this because they have about 40 cars to get through each track session. The cars come in from traveling from the last event, dump all the extra stuff from their car, and wait for their turn to race. Seems pretty grueling. Wife and I may do it, however. The entry fee is low and it seems like it would be a good way to run a bunch of tracks. There aren't a lot of rules but one hard and fast one is to run the same set of tires for the entire event. There was anything from a supercharged Mercedes AMG gull wing to a stock Camry with a 4 cylinder. The turbo-charged Honda mini-van was surprisingly fast. Nissan GTRs win and take a lot of the top spots but this year a Viper was 3rd.

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