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      04-30-2013, 08:34 AM   #1
CSanto
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Fixing Floaty Feeling under Acceleration/Dialing in Stock Suspension

Hey All, I have a few questions about my stock suspension and ways I can dial it in for maximum performance.

For starters I have an 09 EDC Car with 50k miles on it.

It feels as if my suspension/tires aren't as "planted" as they were when the car was younger.

I currently have a floaty feeling on hard acceleration. It's not terrible, but I don't remember that being there when the car was new.

My car also seems to be more "grabby". It grabs at different ruts and grooves in the road. Which again I never remember the car doing that before.

So my question is: Could this be tires? (I have michelin PS2s 255/35 fronts with about 3.5mm of tread left, and 295/35 rears with about 2.5-3mm of tread left)

Could it be alignment? I'm running 0 camber front a rear for the winter. I need an alignment with the summer wheels.

Can it be wheel balancing? I didn't mark front driver/front passenger and rear drive/passenger side.

Is there anything else you guys can think of that's causing the less than optimal performance?

Can this be shock wear?
I'm installing a 585 kit in a few weeks and I want everything to be in tip top shape to handle the added power.

Thanks All!
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      04-30-2013, 12:31 PM   #2
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Couple things I would say is running "0" camber is definitely not ideal. Running an improper alignment really has no benefits even in winter. Tires are far more important for winter traction than say -1.5 degrees of camber and small amount of toe.

If you are at 2.5-3mm of tread left you are on the cusp of the wear bars which I've found on the Michelins once you reach that point the available traction and tramlining you speak of becomes very apparent.

Wheels balancing is much less of a concern...unless you have noticeable vibrations from a poorly balanced wheel/tire.

I would recommend sticking with a proper alignment with minimal cross camber. Alignment specs are floating all around on the sticky above. Replacing your tires soon would probably benefit your car as well. At 50k I wouldn't think your EDC struts are getting "tired" but its possible depending on the type of roads and driving you do. But alignment and tires can make a huge difference on a car like this.
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      04-30-2013, 12:56 PM   #3
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Quote:
Originally Posted by dereksM3 View Post
Couple things I would say is running "0" camber is definitely not ideal. Running an improper alignment really has no benefits even in winter. Tires are far more important for winter traction than say -1.5 degrees of camber and small amount of toe.

If you are at 2.5-3mm of tread left you are on the cusp of the wear bars which I've found on the Michelins once you reach that point the available traction and tramlining you speak of becomes very apparent.

Wheels balancing is much less of a concern...unless you have noticeable vibrations from a poorly balanced wheel/tire.

I would recommend sticking with a proper alignment with minimal cross camber. Alignment specs are floating all around on the sticky above. Replacing your tires soon would probably benefit your car as well. At 50k I wouldn't think your EDC struts are getting "tired" but its possible depending on the type of roads and driving you do. But alignment and tires can make a huge difference on a car like this.

Thanks for the response!
Yeah I think you're right about the wear bars, they are definitely closing in and that could be reason for the grabby feeling.
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      05-07-2013, 10:06 AM   #4
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Anyone else have any input?

I drive rough roads. NYC/bronx/queens. I live on long island but the commute definitely wears on cars.
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      05-07-2013, 12:38 PM   #5
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My PS2s were definitely slipping a lot nearing the end of their life. I switched them for a new set of PSS and it made a world of difference...
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      05-07-2013, 05:30 PM   #6
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Vehicle alignment. That's the issue here 100%
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      05-07-2013, 05:39 PM   #7
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It could very well be worn shocks. Shock life is dependent on the type of driving you do and the roads you drive on. If the roads are not in good condition (not smooth) it will wear the shocks out faster. Hitting potholes and bumps also reduce the life of a shock. You should feel increased bounciness in the ride and it takes more time for the car to "settle" (floating sensation) after hitting a bump when the shocks are worn down.

Tires also make a big difference. If they are worn, a new set of tires will greatly change the way the car feels.
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      05-07-2013, 06:11 PM   #8
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Quote:
Originally Posted by Malek View Post
Vehicle alignment. That's the issue here 100%

Thank you! I will report back after my alignment.
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      05-07-2013, 11:01 PM   #9
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Running a 295 on the back can do that as well. I was running 255/295 and swapped to 275/295. It's definitely different, but not fixed. I think the 295 is too much tire for this car and that's what caused the floating feeling. It seems a lot better with 275s or 285s out back. I do have a proper alignment as well. That being said, I'd like to hear your feedback as well post alignment.
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      05-07-2013, 11:22 PM   #10
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Quote:
Originally Posted by Bmw135er
Running a 295 on the back can do that as well. I was running 255/295 and swapped to 275/295. It's definitely different, but not fixed. I think the 295 is too much tire for this car and that's what caused the floating feeling. It seems a lot better with 275s or 285s out back. I do have a proper alignment as well. That being said, I'd like to hear your feedback as well post alignment.
You are correct. The car does not behave correctly for a number of reasons with a 295 or larger tire out back. The factory suspension parameters and alignment settings need to be abandoned for these sizes to work as well.

Most importantly, if running a large tire out back such as a 295, one should not run an aggressive offset wheel on the front of this car as it further upsets the balance due to track width bias from front to rear.

OP, let me know what your suspension set up is, I can provide you with some parameters to go by to get your M3 back to where it should be.

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      05-08-2013, 08:06 AM   #11
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Quote:
Originally Posted by Malek View Post
OP, let me know what your suspension set up is, I can provide you with some parameters to go by to get your M3 back to where it should be.

Malek
I'm on Stock 09 EDC Suspension. Should I think about doing a tire/wheel swap?
I'm kinda getting tired of the white with black wheel look anyway.
Although, I'm installing a 585 kit in about a week, so I thought having some meatier tires would help.
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      05-09-2013, 07:11 AM   #12
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Quote:
Originally Posted by Bmw135er View Post
Running a 295 on the back can do that as well. I was running 255/295 and swapped to 275/295. It's definitely different, but not fixed. I think the 295 is too much tire for this car and that's what caused the floating feeling. It seems a lot better with 275s or 285s out back. I do have a proper alignment as well. That being said, I'd like to hear your feedback as well post alignment.
I think I can buy some RAC RG63s local to me. If I did those with 255/35 F and 275/35 R would that perform better?
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      07-07-2013, 08:54 AM   #13
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OK so I got a wheel alignment. That helped a bit, but the unstable feeling on acceleration is still there.

I have 19" HRE's with a 10.5 width rear. Would 275/35s fit on that width rim without looking too small?

Are there any cheaper upgrades I can do to my suspension to regain that solid road feel?

Maybe my struts are getting a little tired?
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      07-07-2013, 08:59 AM   #14
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This may sound odd but try adding 4 lbs. of tire pressure and see if this helps. I had the same issue and Jay at GC suggested this and I swear it helped. I did 3lbs front and 4lbs rear. I too am running 295's on the rear. If it doesn't help, no big deal as it costs nothing and it's easily reversible.

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      07-07-2013, 09:01 AM   #15
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Quote:
Originally Posted by BarryC View Post
This may sound odd but try adding 4 lbs. of tire pressure and see if this helps. I had the same issue and Jay at GC suggested this and I swear it helped. I did 3lbs front and 4lbs rear. I too am running 295's on the rear. If it doesn't help, no big deal as it costs nothing and it's easily reversible.

BC
Thats interesting. I'll try it this morning. Just add 3 and 4lbs. I think I'm running 36 psi in the rears. Bring it up to 40?
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      07-07-2013, 09:07 AM   #16
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Quote:
Originally Posted by CSanto View Post
Thats interesting. I'll try it this morning. Just add 3 and 4lbs. I think I'm running 36 psi in the rears. Bring it up to 40?
yep. I'm at 39lbs in the rear and 38 in the front. Jay said that Mich tires "like" a lot of air pressure and I think the sidewalls are soft. I'm assuming lower pressure allows the sidewalls to flex more and so you get that squirm under acceleration. Hopefully it'll help.

Thx,
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      07-07-2013, 09:13 AM   #17
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Quote:
Originally Posted by BarryC View Post
yep. I'm at 39lbs in the rear and 38 in the front. Jay said that Mich tires "like" a lot of air pressure and I think the sidewalls are soft. I'm assuming lower pressure allows the sidewalls to flex more and so you get that squirm under acceleration. Hopefully it'll help.

Thx,
BC
Will try it Barry. Thank you!
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      07-07-2013, 09:20 AM   #18
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An alignment and upgrade to FCAB, shock mounts and suspension bushings might be your answer.
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      07-08-2013, 09:03 AM   #19
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Ok so I was actually running 38psi all the way around, I brought the rears up to 40psi and this actually fixed 90% of the issue!

Thanks Barry!
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      11-04-2013, 08:09 AM   #20
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Ok, I'm bumping this thread because I'm still have some of the issues that I stated in the first post.

The alignment and keeping the PSI up in the tires has fixed the floaty feeling, but the car just doesnt feel as planted and stable as it used to when it was younger.

I have a slight steering wheel vibration at around 80 and higher mph.
Without doing a full suspension is there anything I can do?
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      11-04-2013, 09:06 AM   #21
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I would start with new tires. Worn tires will be very grabby on road imperfections. Set everything back to stock on alignment and see how it feels. If not satisfactory then make one change, and see if it helps before changing anything else. Good luck.
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      11-04-2013, 09:07 AM   #22
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Colder temps probably effecting your traction also.
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