Unstable on 19s?

geko29 · 04-11-2013, 07:29 AM

I got my new summer shoes put on this past Tuesday--19x8.5/9.5 Alufelgen SF-71s wrapped in PSS 235/35/19 and 265/30/19. I was prepared for a harsher ride, but it's not actually too bad from that regard. I'd describe it as more disconcerting than uncomfortable. When I hit small bumps (like a manhole cover or a road seam), the car actually moves sideways, then comes back. This isn't tramlining or bump-steer, per se, because the car doesn't change directions, it just feels very unsettled.

Is this normal? What causes it? I would have expected lower-profile tires to make handling more stable, but it seems to have had exactly the opposite effect.

uniter · 04-11-2013, 10:42 AM

Check your bushings anyway :] A heavier / stiffer wheel can exaggerate problems in the suspension. (The stiffness will also make the car move around more, the tire can't absorb any 'flex' from road imperfections, so they get loaded onto your bushings, then your chassis.)

geko29 · 04-11-2013, 12:23 PM

Would my bushings be shot already at 15k? It's an '11 335d.

The bushings in my E46 started to go at around 85k/10 years.

VMRWheels · 04-11-2013, 01:37 PM

Did you come from RFTs straight to non-RFTs?

geko29 · 04-11-2013, 03:26 PM

No, I had shit RFTs when I bought it ~8 months ago, changed them for 17" Blizzak LM-60s (non-RFT) on the stock wheels about 4-5 months ago, and put these on this week.

practice89 · 04-11-2013, 04:02 PM

have the same problem but i'm on stock m-sport wheels with rfts and kw v1 coiloverss

gaza01 · 04-11-2013, 05:13 PM

check the tyre pressures

geko29 · 04-16-2013, 06:53 AM

Got an alignment yesterday, and while the problem isn't gone totally, it is quite a bit better.

BLAZEDV3 · 06-16-2013, 08:59 PM

I'm experiencing this problem as well. Weird part is my car was fine, I had coilovers installed car still drove fine. Decided to get the mandatory alignment for the coilovers and now my car fishtails a tiny bit over bumps and then snaps back to straight. The alignment shop says it's most likely my tires but if so how was my car fish tail free before the alignment. Will be replacing the tires tomorrow, I'll update with any new finds. If that doesn't solve it I'm going to a more reputable alignment shop.

04-11-2013, 07:29 AM	#1
geko29 Major 1563 Rep 1,422 Posts Drives: 2023 M3 6MT Join Date: May 2012 Location: Illinois, USA iTrader: (2)	Unstable on 19s? I got my new summer shoes put on this past Tuesday--19x8.5/9.5 Alufelgen SF-71s wrapped in PSS 235/35/19 and 265/30/19. I was prepared for a harsher ride, but it's not actually too bad from that regard. I'd describe it as more disconcerting than uncomfortable. When I hit small bumps (like a manhole cover or a road seam), the car actually moves sideways, then comes back. This isn't tramlining or bump-steer, per se, because the car doesn't change directions, it just feels very unsettled. Is this normal? What causes it? I would have expected lower-profile tires to make handling more stable, but it seems to have had exactly the opposite effect. __________________
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04-11-2013, 10:42 AM	#2
uniter Black on Black on Black. 38 Rep 532 Posts Drives: 335i/6mt Sport,Nav,Prem. Join Date: Feb 2010 Location: New Hope, PA iTrader: (1)	Check your bushings anyway :] A heavier / stiffer wheel can exaggerate problems in the suspension. (The stiffness will also make the car move around more, the tire can't absorb any 'flex' from road imperfections, so they get loaded onto your bushings, then your chassis.) __________________ LEMANS BLUE M-TECH E92->PROCEDE REV3::BIEHNTUNE FLASH::ETS 7" FMIC::RACELAND DPS::OS GIKEN 1.5 WAY::DEFIV DIFF LOCKDOWN::DEFIV OCC::DEFIV INTAKE::RB PCV
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04-11-2013, 12:23 PM	#3
geko29 Major 1563 Rep 1,422 Posts Drives: 2023 M3 6MT Join Date: May 2012 Location: Illinois, USA iTrader: (2)	Would my bushings be shot already at 15k? It's an '11 335d. The bushings in my E46 started to go at around 85k/10 years. __________________
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04-11-2013, 01:37 PM	#4
VMRWheels BimmerPost Supporting Vendor 2038 Rep 25,989 Posts Drives: BMW Join Date: Jun 2007 Location: Anaheim, CA iTrader: (4) Garage List 2013 BMW M3 [10.00] 2015 BMW M4 [0.00] 2013 BMW F30 [0.00] 2014 BMW F22 [0.00] 2013 BMW F06 [0.00]	Did you come from RFTs straight to non-RFTs? __________________ VMR\|Wheels \| 714.442.7916 \| sales@velocitymotoring.com \| www.velocitymotoring.com \| facebook \| flickr \| Instagram
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04-11-2013, 03:26 PM	#5
geko29 Major 1563 Rep 1,422 Posts Drives: 2023 M3 6MT Join Date: May 2012 Location: Illinois, USA iTrader: (2)	No, I had shit RFTs when I bought it ~8 months ago, changed them for 17" Blizzak LM-60s (non-RFT) on the stock wheels about 4-5 months ago, and put these on this week. __________________
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04-11-2013, 04:02 PM	#6
practice89 Private 2 Rep 87 Posts Drives: 2022 X6 M50i Join Date: Mar 2013 Location: United States iTrader: (-1)	have the same problem but i'm on stock m-sport wheels with rfts and kw v1 coiloverss
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04-11-2013, 05:13 PM	#7
gaza01 Colonel 105 Rep 2,692 Posts Drives: E92 335i Join Date: Dec 2010 Location: London iTrader: (3)	check the tyre pressures
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04-16-2013, 06:53 AM	#8
geko29 Major 1563 Rep 1,422 Posts Drives: 2023 M3 6MT Join Date: May 2012 Location: Illinois, USA iTrader: (2)	Got an alignment yesterday, and while the problem isn't gone totally, it is quite a bit better. __________________
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06-16-2013, 08:59 PM	#9
BLAZEDV3 New Member 0 Rep 22 Posts Drives: 335i Join Date: Aug 2012 Location: Toronto iTrader: (0)	I'm experiencing this problem as well. Weird part is my car was fine, I had coilovers installed car still drove fine. Decided to get the mandatory alignment for the coilovers and now my car fishtails a tiny bit over bumps and then snaps back to straight. The alignment shop says it's most likely my tires but if so how was my car fish tail free before the alignment. Will be replacing the tires tomorrow, I'll update with any new finds. If that doesn't solve it I'm going to a more reputable alignment shop.
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