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      11-15-2011, 11:31 PM   #1
disapr
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Pilot Sport Cup - Camber settings?

Michelin Pilot Sport Cup users - What camber settings are you running?

I've read the PDF that covers adjusting the camber based on temperature but that seems like a lengthy method if someone already has a working configuration that I can at least use as a baseline.

I'm currently at 2.2 F on my RE-11's and the fronts are looking pretty chewed up on the outer shoulder.

Thanks!
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      11-16-2011, 03:32 AM   #2
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Garage List
2009 BMW M3 E92  [10.00]
2.6 in front, 2.3 in the back.
2.3 bar warm, starting with 1.8 - 1.9 cold.
No chewed up outer shoulder.
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      11-16-2011, 05:16 AM   #3
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I use PSC on my e46 M3 and I'm running 3.6 deg of neg camber; however, with the e9x M3 you can get away with a little less neg camber so I'd recommend starting somewhere in the 2.5-3.0 deg range, probably closer to 3.0, to get the most out of the tire. R-comps like neg camber!

Is this a street-track car or dedicated track car? Obviously running -3 deg of camber on the street is not the greatest for tire longevity.
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      11-16-2011, 06:57 AM   #4
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how long do theses tyres last on the streets
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      11-16-2011, 07:21 AM   #5
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Quote:
Originally Posted by ole85 View Post
how long do theses tyres last on the streets
I've never used a set only on the street so I'd guess maybe 5-6k of street-only miles? However, the bigger problem you'll run into is wet weather driving - tires have OK hydroplane resistance at full tread depth but will quickly become dangerous in the wet, especially when there's standing water. The PSC+ have additional grooves/channels in them compared to the PSC but I doubt the grooves result in a significant improvement in wet weather performance. Why not buy an extreme performance summer tire (RE11, AD08, etc) instead? Lose dry performance but gain wet performance.
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      11-16-2011, 08:31 AM   #6
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Quote:
Originally Posted by TobiasMUC View Post
2.6 in front, 2.3 in the back.
2.3 bar warm, starting with 1.8 - 1.9 cold.
No chewed up outer shoulder.
Thanks - That shouldn't be too bad on the street driving to the track

Quote:
Originally Posted by dbarnes View Post
Is this a street-track car or dedicated track car? Obviously running -3 deg of camber on the street is not the greatest for tire longevity.
It's mixed use but it only sees 300 or so miles per month on the street and a many track days as I can make time for.
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      11-16-2011, 09:42 AM   #7
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Quote:
Originally Posted by disapr View Post

It's mixed use but it only sees 300 or so miles per month on the street and a many track days as I can make time for.
Then I'd try running the front as close to -3.0 deg and the rear around -2.0 deg, if you want to maximize track performance.

I've also learned over the years if you keep the PSC hot tire pressure at or below 40 psi they won't get greasy during a 30-45 minute track session.

Are you planning on using the PSC or PSC+? I have no experience with the "+" version.
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      11-16-2011, 10:23 AM   #8
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I have the standard pilot cup tire, not the + version.

How badly is -3.0 camber going to cut the inside of my tires when I'm on the street? At 2.2 it's really not doing very much that isn't evened out on the track so I don't know if that will really change much.

TobiasMUC - Are you running the same pressure all around?

In this document they are using more pressure in the rear. This seems more appropriate for a rear/mid engine car.
http://www.tirerack.com/tires/tirete...nd_Feeding.pdf
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      11-16-2011, 10:45 AM   #9
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Quote:
Originally Posted by disapr View Post
I have the standard pilot cup tire, not the + version.

How badly is -3.0 camber going to cut the inside of my tires when I'm on the street? At 2.2 it's really not doing very much that isn't evened out on the track so I don't know if that will really change much.

TobiasMUC - Are you running the same pressure all around?

In this document they are using more pressure in the rear. This seems more appropriate for a rear/mid engine car.
http://www.tirerack.com/tires/tirete...nd_Feeding.pdf
With a lot of street driving only it will fairly quickly wear out the inside edge.

Based on your street driving I assumed you'd want to maximize settings for the track but if you want a better street-track friendly setup then I'd go with -2.5 front and -1.8 rear (typically want rear to be about 1deg less but -1.5 is definitely not enough camber for a r-comp that's driven on the track).

No, rear pressures should be higher than front. I usually start with a 2psi delta between the front and rear with a higher rear pressure, and then adjust for track conditions and temp.
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      11-16-2011, 11:01 AM   #10
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I'm running -2.2|-2.2 F / -2.0|-2.0 R right now. My rear RE-11 looks fine but the front is getting rolled a bit. My point is that 2.0 in the rear is fine so I'll probably adjust the front to 2.6 or so. The RE-11's might also benefit from a little more
camber.

Can someone explain why you would want more pressure in the rear? I can make some assumptions but I'd like to know the real reason.

Front RE-11 @ -2.2 Camber:
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      11-16-2011, 03:42 PM   #11
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Part of the problem with your street tires is the tread block depth. If you have significant tread depth then camber alone won't completely solve excessive wear of the outer tread blocks. Also, you can get excessive heat buildup in tall tread blocks which results in more lateral deformation and increased wear. That's why race tires, even r-comps, have a lot less tread depth. Shaving most r-comps will result in better lap times because it minimizes what tread squirm there is.

Here's a good article discussing tire pressures:
http://www.turnfast.com/tech_handling/handling_pressure

Another rule-of-thumb for front engine, rear drive cars is (works for all BMWs I've driven on the track): to reduce oversteer you can either increase rear tire pressure or decrease front tire pressure; and to reduce understeer you can either decrease rear tire pressure or increase front tire pressure. The next time you are at the track play around with tire pressures to see the effect it has on handling characteristics - fine tune the handling and braking balance of your car!

Last edited by M3SQRD; 11-16-2011 at 07:02 PM..
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      11-16-2011, 04:26 PM   #12
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Good info, thanks for the link. I suppose I should shop around for a good pyro so that I can dial in my pressure and camber exactly.

Just for clarification: Wouldn't less tire pressure typically increase traction? (Assuming that it's within range for the tire) It seems like less pressure in the front and/or more pressure in the rear would magnify over steer, not decrease it.

Either way I will spend some time adjusting pressure and testing this at the track. I found that the RE-11's worked best for me at 33psi hot on all corners. With the cups I'll take this info as a starting point and try to fine tune it from there.

Thanks
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      11-16-2011, 05:00 PM   #13
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Quote:
Originally Posted by dbarnes View Post
Part of the problem with your street tires is the tread block depth. If you have significant tread depth then camber alone won't completely solve excessive wear of the outer tread blocks. Also, you can get excessive heat buildup in tall tread blocks which results in more lateral deformation and increased wear. That's why race tires, even r-comps, have a lot less tread depth. Shaving most r-comps will result in better lap times because it minimizes what tread squirm there is.

Here's a good article discussing tire pressures:
http://www.turnfast.com/tech_handling/handling_pressure

Another rule-of-thumb for front engine, rear drive cars is (works for all BMWs I've driven on the track): increase rear tire pressure or decrease front tire pressure to reduce oversteer, and decrease rear tire pressure or increase front tire pressure to reduce understeer. The next time you are at the track play around with tire pressures to see the effect it has on handling characteristics - fine tune the handling and braking balance of your car!
what about running the same pressure all around?

i was running 31 cold F 32-33 cold R on my stock CS3s
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      11-16-2011, 05:16 PM   #14
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Quote:
Originally Posted by dbarnes View Post
Another rule-of-thumb for front engine, rear drive cars is (works for all BMWs I've driven on the track): increase rear tire pressure or decrease front tire pressure to reduce oversteer, and decrease rear tire pressure or increase front tire pressure to reduce understeer. The next time you are at the track play around with tire pressures to see the effect it has on handling characteristics - fine tune the handling and braking balance of your car!
dbarnes thanks for the insight...but one clarification. What excactly where u saying here: " increase rear tire pressure or decrease front tire pressure to reduce oversteer, and decrease rear tire pressure or increase front tire pressure to reduce understeer" ??

Seems the two statements contradict each other unless I'm reading it wrong.
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      11-16-2011, 05:57 PM   #15
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J for your car use keep it -2.6 to -2.8 front and 2.0 rear. Going over -3.0 front will kill the inside of your tires, especially Cup tires where the tread is much less vs. street tires.

RE-11 is known to wear on the outer edge when the pressure and camber are not optimal. Also why I switched to AD08 where the tread design is more "wear friendly".

In terms of pressure, Michelin has a good quick start guide in terms of how to set up the tire pressure and camber. http://www.tirerack.com/tires/tirete...nd_Feeding.pdf

Last thing to keep in mind is that the optimal set up for the race track will most likely not work for extended street driving. You can only make trade offs and find a middle point which works OK (not great) for both.
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      11-16-2011, 06:20 PM   #16
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Quote:
Originally Posted by dapopa9 View Post
dbarnes thanks for the insight...but one clarification. What excactly where u saying here: " increase rear tire pressure or decrease front tire pressure to reduce oversteer, and decrease rear tire pressure or increase front tire pressure to reduce understeer" ??

Seems the two statements contradict each other unless I'm reading it wrong.
No. Assuming you have your "hot" tire pressures dialed in, not "cold", and the handlling is off then to reduce (dial out) understeer or oversteer you would adjust the tire pressures as listed above. The difference being "hot" vs "cold" and "fine tuning" of the handling characteristics. You still first need to figure out what "cold" F and R tire pressures to start with. I left this out because I assumed people would read the article.

BTW, the delta psi I posted above is "cold" and on a dedicated track car so I would not recommend anyone use that as a starting point.

Also, PSC tires can easily handle over -3 deg of neg camber and perform extremely well, even without shaving. I certainly would not recommend over -2.5 deg for a street tire.
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      11-16-2011, 06:25 PM   #17
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Quote:
Originally Posted by dbarnes View Post
No. Assuming you have your "hot" tire pressures dialed in, not "cold", and the handlling is off then to reduce (dial out) understeer or oversteer you would adjust the tire pressures as listed above. The difference being "hot" vs "cold" and "fine tuning" of the handling characteristics. You still first need to figure out what "cold" F and R tire pressures to start with. I left this out because I assumed people would read the article.

BTW, the delta psi I posted above is "cold" and on a dedicated track car so I would not recommend anyone use that as a starting point.

Also, PSC tires can easily handle over -3 deg of neg camber and perform extremely well, even without shaving. I certainly would not recommend over -2.5 deg for a street tire.
I was just quoting the part of the increase/decrease of pressure..you actually say to increase/decrease both the front and back all at the same time which is contradicting in itself...I think you were meaning to say to - Reduce Understeer decrease front and increase rear.

BTW great article you posted!
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      11-16-2011, 06:31 PM   #18
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Quote:
Originally Posted by persian54 View Post
what about running the same pressure all around?

i was running 31 cold F 32-33 cold R on my stock CS3s
If you've checked "hot" tire pressures and temps then yes you could potentially start with the same "cold" F and R pressures. There are other variables like F/R spring rate, sway bar stiffness/setting, cross weights, tires staggered/unstaggered, etc. that come into play.

By the end of a session are your lap times remaining consistent or dropping off? Is the balance of the car changing? Are the tires getting greasy? If things feel great and lap times aren't dropping off then you have good "cold" pressures.

Also, make sure to adjust your "cold" temps for changes in ambient temp - people forget this a lot and don't bleed off pressure from the morning to afternoon and then can't figure out why their car is handling differently!
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      11-16-2011, 06:35 PM   #19
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Quote:
Originally Posted by dbarnes View Post
If you've checked "hot" tire pressures and temps then yes you could potentially start with the same "cold" F and R pressures. There are other variables like F/R spring rate, sway bar stiffness/setting, cross weights, tires staggered/unstaggered, etc. that come into play.

By the end of a session are your lap times remaining consistent or dropping off? Is the balance of the car changing? Are the tires getting greasy? If things feel great and lap times aren't dropping off then you have good "cold" pressures.

Also, make sure to adjust your "cold" temps for changes in ambient temp - people forget this a lot and don't bleed off pressure from the morning to afternoon and then can't figure out why their car is handling differently!
I've had session where it's pretty greasy.... but this was when i ran stock psi (35)

once i dropped them to 31/32, things got significantly better.

Lap times for me are a strange thing... I tend to have my off days and on days. I have had better lap times in 100+ heat than I have in cooler days, and vice versa...
So I can't say if they improved due to tire pressure or not

31/32 cold goes up to about 40 hot on hot days, 38-39 on cooler days

35 cold went way past 40...X.x.
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      11-16-2011, 06:35 PM   #20
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Quote:
Originally Posted by dapopa9 View Post
I was just quoting the part of the increase/decrease of pressure..you actually say to increase/decrease both the front and back all at the same time which is contradicting in itself...I think you were meaning to say to - Reduce Understeer decrease front and increase rear.

BTW great article you posted!
You can do "either" not both. For example, to deal with oversteer you could increase R pressure OR decrease front pressure. However, let's say you increased rear but then under braking your rear starts to dance then you'd go back and drop the R pressure back to what it was before you raised it and then lower the F to get rid of the oversteer.

Please note, we are assuming all other varables are not being adjusted otherwise things can get complicated fast!
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      11-16-2011, 06:40 PM   #21
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Quote:
Originally Posted by persian54 View Post
I've had session where it's pretty greasy.... but this was when i ran stock psi (35)

once i dropped them to 31/32, things got significantly better.

Lap times for me are a strange thing... I tend to have my off days and on days. I have had better lap times in 100+ heat than I have in cooler days, and vice versa...
So I can't say if they improved due to tire pressure or not

31/32 cold goes up to about 40 hot on hot days, 38-39 on cooler days

35 cold went way past 40...X.x.
Then it sounds like your starting pressures are OK once you adjusted them down. However, if you consistently run better lap times on a hot day then you should adjust your cold pressures up a couple of psi on cold days so hot pressures are always at 40 psi.

BTW, sorry to read about the nut job
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      11-16-2011, 07:32 PM   #22
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Quote:
Originally Posted by dbarnes View Post
You can do "either" not both. For example, to deal with oversteer you could increase R pressure OR decrease front pressure. However, let's say you increased rear but then under braking your rear starts to dance then you'd go back and drop the R pressure back to what it was before you raised it and then lower the F to get rid of the oversteer.

Please note, we are assuming all other varables are not being adjusted otherwise things can get complicated fast!
ahh ok I follow you now!
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