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      02-02-2012, 01:19 AM   #1
michaelalex17
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change bushings to reduce understeer?

i dont know much about suspension components. i am trying to reduce understeer in my 335xi. i have Bilstein Sport shocks and H&R sport springs. i was also thinking about getting a rear sway bar. from what i heard getting just the rear sway bar will help more then getting both the front and rear because tightening up the front will still make me have understeer. if this is wrong please correct me. i was also curious if i should change my bushings? would this help reduce understeer? if so should i just do the rear like the sway bar or do i change the front and rear to help reduce understeer? thanks
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      02-08-2012, 10:21 PM   #2
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I just spoke to Sal at ACM about this.. Yes.. It is highly recommended.. Let me know how it goes if you do bc I'm interested in the same.. Good choice of mods bro
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      02-09-2012, 08:10 PM   #3
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stiffer bushings? yes it will help with handling.
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      02-10-2012, 12:00 AM   #4
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I heard good thing about just installing a rear sway bar too. Keep us posted if you go through with it
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      02-14-2012, 01:39 PM   #5
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will do
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      02-28-2012, 08:31 PM   #6
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I just did this on my car. Its rather noticeable, but I can't really push my winter tires hard enough to really find out. I also recommend camber plates if you're attempting to reduce understeer.
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      02-29-2012, 12:21 PM   #7
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One of the easiest, cheapest and first things you should do to neutralize an AWD car's handling by reducing understeer is managing tire pressures closely, and selecting tire widths appropriately.

Don't rush to 265s or 275s for the rear wheel's tire widths. Everyone's all about width on the rears, and it's only hurting the understeer problem. Secondly, you should be running more tire pressure on the rears than the fronts. I run 36psi rear, and 32 front. While the car isn't neutral, it's really not too far off. With DTC on, I can send the ass out on a ramp without too much trouble at all.

Rear sway bar certainly will help, and bushings maybe a little.
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      03-01-2012, 11:58 AM   #8
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Quote:
Originally Posted by AWD Addict View Post
One of the easiest, cheapest and first things you should do to neutralize an AWD car's handling by reducing understeer is managing tire pressures closely, and selecting tire widths appropriately.

Don't rush to 265s or 275s for the rear wheel's tire widths. Everyone's all about width on the rears, and it's only hurting the understeer problem. Secondly, you should be running more tire pressure on the rears than the fronts. I run 36psi rear, and 32 front. While the car isn't neutral, it's really not too far off. With DTC on, I can send the ass out on a ramp without too much trouble at all.

Rear sway bar certainly will help, and bushings maybe a little.
i thought most people put more psi in the front tires to reduce understeer?
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      03-01-2012, 12:20 PM   #9
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this is from tirerack.com

adjustments Decrease Understeer Decrease Oversteer
Front Tire Pressure Higher Lower
Rear Tire Pressure Lower Higher
Front Tire Section Larger Smaller
Rear Tire Section Smaller Larger
Front Wheel Camber More Negative More Positive
Rear Wheel Camber More Positive More Negative
Front Wheel Toe Toward Toe-Out Toward Toe-In
Rear Wheel Toe Toward Toe-In Toward Toe-Out
Front Wheel Caster More Positive More Negative
Front Springs Soften Stiffen
Rear Springs Stiffen Soften
Front Anti-sway Bar Soften (Thinner) Stiffen (Thicken)
Rear Anti-sway Bar Stiffen (Thicker) Soften (Thinner)
Weight Distribution More Rearward More Forward
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      03-01-2012, 09:58 PM   #10
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As mentioned above:

For Turn-in: Add a bit of Camber, Slightly stiffer rear sway, and the appropriate choice of Springs & Struts/Shocks or go to decent coil-overs:

For Continuing the rotation after turn-in, put a LSD (same as for a 335i) in. This will keep you from losing power in the rear, therefore note getting a higher ration of power up front. That is a big source of the understeer with these cars. I have a Wavetrac, and the rear-end really hooks up well now on the track.
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      03-08-2012, 09:08 AM   #11
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Quote:
Originally Posted by michaelalex17 View Post
i thought most people put more psi in the front tires to reduce understeer?
Higher pressure = smallercontact patch = less grip. It also means a stiffer sidewall.

Understeer/pushing is when the front breaks traction before the rear.
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      03-14-2012, 12:13 AM   #12
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Quote:
Originally Posted by AWD Addict
Quote:
Originally Posted by michaelalex17 View Post
i thought most people put more psi in the front tires to reduce understeer?
Higher pressure = smallercontact patch = less grip. It also means a stiffer sidewall.

Understeer/pushing is when the front breaks traction before the rear.
Thanks for the intel. I've been running 38psi all the way around because they told me to do that when I took it to the track.
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Last edited by ccraig13; 03-14-2012 at 12:21 AM. Reason: Explained the reason for my madness
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      03-18-2012, 02:35 PM   #13
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so should i just get two of each of these:

http://www.ecstuning.com/Search/ES57...aign=postreply
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      05-06-2012, 04:09 PM   #14
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Quote:
Originally Posted by AWD Addict View Post
One of the easiest, cheapest and first things you should do to neutralize an AWD car's handling by reducing understeer is managing tire pressures closely, and selecting tire widths appropriately.

Don't rush to 265s or 275s for the rear wheel's tire widths. Everyone's all about width on the rears, and it's only hurting the understeer problem. Secondly, you should be running more tire pressure on the rears than the fronts. I run 36psi rear, and 32 front. While the car isn't neutral, it's really not too far off. With DTC on, I can send the ass out on a ramp without too much trouble at all.

Rear sway bar certainly will help, and bushings maybe a little.
ok so someone please confirm this. lets say there is 35psi in all my tires and i want to reduce understeer. and lets say it is within spec to increase the pressure to 38psi. so if i put in like 43 psi it would techincally be putting in more air in the front tire but it would actually negatively affect handling because its to much air. so ideally i would put in the 38 psi up front and leave the rears with 35psi or even go down to like 34psi. that way i have the perfect contact patch up front and less grip in the rear. wouldnt this be beneficial in terms of reducing understeer?
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      05-07-2012, 08:30 AM   #15
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Quote:
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so ideally i would put in the 38 psi up front and leave the rears with 35psi or even go down to like 34psi. that way i have the perfect contact patch up front and less grip in the rear. wouldnt this be beneficial in terms of reducing understeer?
No, that would have the opposite effect. When you raise the tire pressure you decrease traction (the size of your contact patch). To make your car less prone to understeer you would want to run higher pressure in the rear than in the front.
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      05-07-2012, 11:57 AM   #16
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Quote:
Originally Posted by tomtom11 View Post
ok so someone please confirm this. lets say there is 35psi in all my tires and i want to reduce understeer. and lets say it is within spec to increase the pressure to 38psi. so if i put in like 43 psi it would techincally be putting in more air in the front tire but it would actually negatively affect handling because its to much air. so ideally i would put in the 38 psi up front and leave the rears with 35psi or even go down to like 34psi. that way i have the perfect contact patch up front and less grip in the rear. wouldnt this be beneficial in terms of reducing understeer?
No. You'll be adding to your understeer issue with that.

You want higher PSI in the rears, and less up front. 32F/36R works pretty nicely for me. With DTC on, the car feels really good. Predictable and neutral.
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      05-07-2012, 12:23 PM   #17
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No. You'll be adding to your understeer issue with that.

You want higher PSI in the rears, and less up front. 32F/36R works pretty nicely for me. With DTC on, the car feels really good. Predictable and neutral.
i dont think thats really true since your fronts dont have ideal contact patch. 36 maybe fine in the rear but 32 up front is to low
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