Tire/wheel question for destaggered setup
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From: San Francisco
88 BMW M3, 11 BMW M3 Vert, 04 Porsche GT3
Tire/wheel question for destaggered setup
After owning the C32 since 2003 and with only 72k miles, I've decided to turn it loose for a few track events and have some fun. I've read numerous threads regarding handling of the C32 and it's tendency to understeer. I also read that the understeer can be reduced by destaggering the tire/wheel setup. I recently came a cross a set of the c32 rear 17x8.5 rims and purchased them. From all the information I could gather, it appears that 245/40/17 is a good for the destaggered setup. I've read that 245/40/17 on the rear rims will fit in the front. What I want to know is will I need to roll my fenders in order to accomplish this?
Just want to make sure since the track event I am going to is coming up the day after Christmas (Thunderhill) so need to order tires now. I plan on getting the star specs as my track oriented tires.
Thanks.
Just want to make sure since the track event I am going to is coming up the day after Christmas (Thunderhill) so need to order tires now. I plan on getting the star specs as my track oriented tires.
Thanks.
Last edited by inflectionpt; Dec 7, 2011 at 08:51 PM.
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From: Seattle, Warshington
2005 C55, 2006 Ram 2500 MegaCab diesel, sold 2001 Dodge 2500 Cummins, sold 87 190e-16v, sold 97 e420
After owning the C32 since 2003 and with only 72k miles, I've decided to turn it loose for a few track events and have some fun. I've read numerous threads regarding handling of the C32 and it's tendency to understeer. I also read that the understeer can be reduced by destaggering the tire/wheel setup. I recently came a cross a set of the c32 rear 17x8.5 rims and purchased them. From all the information I could gather, it appears that 245/40/17 is a good for the destaggered setup. I've read that 245/40/17 on the rear rims will fit in the front. What I want to know is will I need to roll my fenders in order to accomplish this?
Just want to make sure since the track event I am going to is coming up the day after Christmas (Thunderhill) so need to order tires now. I plan on getting the star specs as my track oriented tires.
Thanks.
Just want to make sure since the track event I am going to is coming up the day after Christmas (Thunderhill) so need to order tires now. I plan on getting the star specs as my track oriented tires.
Thanks.
Your springs or tire pressures may be the cause. I run KMac bushings upfront with 1.5 degrees negative camber and have a car that oversteers, I can dial that out with tire pressure but I react better to oversteer than understeer.
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88 BMW M3, 11 BMW M3 Vert, 04 Porsche GT3
How's the ride with the kmac bushings? I know that will give you a lot more control in terms of suspension setup but my intent is not to setup the car with harsh ride.
There are numerous things that can cause understeer and can fix it without eliminating forward traction. If you destagger, you will end up with a drift car and go slower.
Your springs or tire pressures may be the cause. I run KMac bushings upfront with 1.5 degrees negative camber and have a car that oversteers, I can dial that out with tire pressure but I react better to oversteer than understeer.
Your springs or tire pressures may be the cause. I run KMac bushings upfront with 1.5 degrees negative camber and have a car that oversteers, I can dial that out with tire pressure but I react better to oversteer than understeer.
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Verify proper 245/40/17 clearance before getting after it. My current Michelin Pilot Super Sports are quite close to the MacPherson struts.
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88 BMW M3, 11 BMW M3 Vert, 04 Porsche GT3
I guess I just have to get the tires (thinking star specs) and see if they fit.
Yup, many here have swapped OE AMG 17x8.5 34 ET wheels up front. Gleaned that understeer-reducing upgrade from this forum years ago.
Verify proper 245/40/17 clearance before getting after it. My current Michelin Pilot Super Sports are quite close to the MacPherson struts.
Verify proper 245/40/17 clearance before getting after it. My current Michelin Pilot Super Sports are quite close to the MacPherson struts.
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From: virginia beach
clk 500 (wifey's); 350Z roadster (daily driver); 350Z coupe (track car)
MB's (like many cars nowadays) have HUGE amounts of understeer built into the design, not because of the designers, but because of lawyers!!!!!!! 
Going to a square set-up is really step #1 to deal with that, which is why most dedicated track cars (with the exception of the Porsche guys) are set up that way.
It is also very helpful as you can rotate your tires very easily (assuming you are running a clockwise road course, that driver-side front tire really takes a beating!).
Regarding tires, I think the Star Specs are a great choice - very grippy (for a non R-comp tire) and last a long time.
Good luck and have fun
Going to a square set-up is really step #1 to deal with that, which is why most dedicated track cars (with the exception of the Porsche guys) are set up that way.
It is also very helpful as you can rotate your tires very easily (assuming you are running a clockwise road course, that driver-side front tire really takes a beating!).
Regarding tires, I think the Star Specs are a great choice - very grippy (for a non R-comp tire) and last a long time.
Good luck and have fun
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Joined: May 2010
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From: Seattle, Warshington
2005 C55, 2006 Ram 2500 MegaCab diesel, sold 2001 Dodge 2500 Cummins, sold 87 190e-16v, sold 97 e420
The biggest ride quality degredation I got was going to extreme dry tires but that is something I can live with :-)
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Senior Member
Joined: May 2010
Posts: 380
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From: Seattle, Warshington
2005 C55, 2006 Ram 2500 MegaCab diesel, sold 2001 Dodge 2500 Cummins, sold 87 190e-16v, sold 97 e420
MB's (like many cars nowadays) have HUGE amounts of understeer built into the design, not because of the designers, but because of lawyers!!!!!!!
Going to a square set-up is really step #1 to deal with that, which is why most dedicated track cars (with the exception of the Porsche guys) are set up that way.
It is also very helpful as you can rotate your tires very easily (assuming you are running a clockwise road course, that driver-side front tire really takes a beating!).
Regarding tires, I think the Star Specs are a great choice - very grippy (for a non R-comp tire) and last a long time.
Good luck and have fun
Going to a square set-up is really step #1 to deal with that, which is why most dedicated track cars (with the exception of the Porsche guys) are set up that way.
It is also very helpful as you can rotate your tires very easily (assuming you are running a clockwise road course, that driver-side front tire really takes a beating!).
Regarding tires, I think the Star Specs are a great choice - very grippy (for a non R-comp tire) and last a long time.
Good luck and have fun
To run at the track with street tires, tire pressure needs to be increased significantly to prevent the sidewalls from rolling over. Next to solve balance issues, the rears can be slightly over or under inflated to dial some of that out. These is the no dollar fix.
The next best dollar fix is with dialing in negative camber, marking your tires and observing the wear pattern under hard cornering to determine if you have an optimal contact patch.
Need I say more?
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From: virginia beach
clk 500 (wifey's); 350Z roadster (daily driver); 350Z coupe (track car)
I suggest you research on other forums where people actually use their cars for driving on track. The M3 guys are probably a good source. Example:
http://forum.e46fanatics.com/showthread.php?t=729224
Again, conventional wisdom is that in cars such as MB, BMW etc., a severely staggered set-up (like 235F/275R) will exacerbate the understeer issue. It will make you slow in turns because of "push" and therefore slow on track.
BTW, I am not an expert by any means. I have just tried to learn from others in the 50 plus track weekends I have attended in the past 3 and 1/2 years.
Let us know which direction you take!
Senior Member
Joined: May 2010
Posts: 380
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From: Seattle, Warshington
2005 C55, 2006 Ram 2500 MegaCab diesel, sold 2001 Dodge 2500 Cummins, sold 87 190e-16v, sold 97 e420
OP: As you see, there can be differing opinions!
I suggest you research on other forums where people actually use their cars for driving on track. The M3 guys are probably a good source. Example:
http://forum.e46fanatics.com/showthread.php?t=729224
Again, conventional wisdom is that in cars such as MB, BMW etc., a severely staggered set-up (like 235F/275R) will exacerbate the understeer issue. It will make you slow in turns because of "push" and therefore slow on track.
BTW, I am not an expert by any means. I have just tried to learn from others in the 50 plus track weekends I have attended in the past 3 and 1/2 years.
Let us know which direction you take!
I suggest you research on other forums where people actually use their cars for driving on track. The M3 guys are probably a good source. Example:
http://forum.e46fanatics.com/showthread.php?t=729224
Again, conventional wisdom is that in cars such as MB, BMW etc., a severely staggered set-up (like 235F/275R) will exacerbate the understeer issue. It will make you slow in turns because of "push" and therefore slow on track.
BTW, I am not an expert by any means. I have just tried to learn from others in the 50 plus track weekends I have attended in the past 3 and 1/2 years.
Let us know which direction you take!
And in case you think I am just a street punk, you can see my posts
http://youtu.be/x3CQsaTUNsw
I've got plenty more autox posts if you would like too.
