135i Rear Toe Arms

ASAP · 05-11-2016, 03:30 AM

Does anyone have experience with any upgraded rear toe arms? One issue that is imho near tragic on the 135i, is side to side deflection / rear end flex on hard acceleration... the car literally bounces side to side. My car had the M3 rear subframe bushings done and this fixed the up and down bounciness but the car had insane side to side flex when accelerating onto a highway ramp or any scenario of that sort. Does anyone know what fixes this?

titium · 05-11-2016, 05:04 AM

Megan racing toe arms and m3 guide rods.

tuj · 05-11-2016, 07:41 AM

I'm no expert, but it would seem to me like the issue is the bushings in play here, not the arms themselves. I would think switching to poly bushings or even better, spherical bushings, would probably help a lot.

ASAP · 05-11-2016, 07:44 AM

Quote:

Originally Posted by tuj

I'm no expert, but it would seem to me like the issue is the bushings in play here, not the arms themselves. I would think switching to poly bushings or even better, spherical bushings, would probably help a lot.

This can't be that difficult, someone has to have a definitive answer to this as it is an obvious problem... so obvious that it almost makes the car dangerous.

tuj · 05-11-2016, 08:15 AM

What are you alignment specs?

ASAP · 05-11-2016, 08:17 AM

Quote:

Originally Posted by tuj

What are you alignment specs?

Whatever OEM is for the car... but i have a much wider rear tire w lighter rims on koni yellows.

chris82 · 05-11-2016, 08:28 AM

Quote:

Originally Posted by ASAP

Whatever OEM is for the car... but i have a much wider rear tire w lighter rims on koni yellows.

What about the rear trailing arms? For safety purposes, the arm should remain stock so in a crash it bends away from the fuel tank (arm is identical on M3), but you can upgrade the bushings. No expert, but don't people usually point to the RTAB when it comes to an unstable rear?

tuj · 05-11-2016, 08:33 AM

I dunno, this sounds like it could be an out-of-alignment setup or perhaps a bent rear suspension arm??? I have my car bone stock, and I get instability in the rear accelerating out of slow corners at the track. It's not that bad, it's just slower than it should be.

How are you determining you have side-to-side flex in the RSF?

ASAP · 05-11-2016, 08:40 AM

Quote:

Originally Posted by tuj

I dunno, this sounds like it could be an out-of-alignment setup or perhaps a bent rear suspension arm??? I have my car bone stock, and I get instability in the rear accelerating out of slow corners at the track. It's not that bad, it's just slower than it should be.

How are you determining you have side-to-side flex in the RSF?

What else would flex in the rear?

This happens on hard straighline acceleration, its so bad and disconcerning... suspension is fine.

fe1rx · 05-11-2016, 10:42 AM

Quote:

Originally Posted by ASAP

... suspension is fine.

Clearly not.

ASAP · 05-11-2016, 10:44 AM

Quote:

Originally Posted by fe1rx

Quote:

Originally Posted by ASAP

... suspension is fine.

Clearly not.

are you saying something is damaged or bent? Because I know that is not the case.

tuj · 05-11-2016, 11:23 AM

How many miles on the car? I'm thinking perhaps worn bushings? (not RSFB but the other bushings)

MightyMouseTech · 05-11-2016, 11:23 AM

Quote:

Originally Posted by ASAP

are you saying something is damaged or bent? Because I know that is not the case.

Sounds like a bad alignment to me.

ShocknAwe · 05-11-2016, 11:33 AM

Quote:

Originally Posted by MightyMouseTech

Sounds like a bad alignment to me.

Easiest thing to start with IMO

ASAP · 05-11-2016, 11:47 AM

Quote:

Originally Posted by tuj

How many miles on the car? I'm thinking perhaps worn bushings? (not RSFB but the other bushings)

65k

ASAP · 05-11-2016, 11:48 AM

Quote:

Originally Posted by MightyMouseTech

Quote:

Originally Posted by ASAP

are you saying something is damaged or bent? Because I know that is not the case.

Sounds like a bad alignment to me.

What spec would you recommend?

MightyMouseTech · 05-11-2016, 11:56 AM

Quote:

Originally Posted by ASAP

Quote:

Originally Posted by MightyMouseTech

Quote:

Originally Posted by ASAP

are you saying something is damaged or bent? Because I know that is not the case.

Sounds like a bad alignment to me.

What spec would you recommend?

Most important is rear toe. The more positive you go, the more stable it is. There is quite the range within the factory specs.

Maybe try 0.15 deg toe in on both sides.

ASAP · 05-11-2016, 12:07 PM

Quote:

Originally Posted by MightyMouseTech

Quote:

Originally Posted by ASAP

Quote:

Originally Posted by MightyMouseTech

Quote:

Originally Posted by ASAP

are you saying something is damaged or bent? Because I know that is not the case.

Sounds like a bad alignment to me.

What spec would you recommend?

Most important is rear toe. The more positive you go, the more stable it is. There is quite the range within the factory specs.

And this will help with striaght line acceleration side to side flex? I am just not sure how...

MightyMouseTech · 05-11-2016, 12:22 PM

Quote:

Originally Posted by ASAP

And this will help with striaght line acceleration side to side flex? I am just not sure how...

The further toed out the car is, the more "lively" the back end will be when accelerating hard.

HP Autosport · 05-11-2016, 02:37 PM

Quote:

Originally Posted by ASAP

Does anyone have experience with any upgraded rear toe arms? One issue that is imho near tragic on the 135i, is side to side deflection / rear end flex on hard acceleration... the car literally bounces side to side. My car had the M3 rear subframe bushings done and this fixed the up and down bounciness but the car had insane side to side flex when accelerating onto a highway ramp or any scenario of that sort. Does anyone know what fixes this?

What is your alignment setting?

ASAP · 05-11-2016, 02:39 PM

Quote:

Originally Posted by HP Autosport

Quote:

Originally Posted by ASAP

Does anyone have experience with any upgraded rear toe arms? One issue that is imho near tragic on the 135i, is side to side deflection / rear end flex on hard acceleration... the car literally bounces side to side. My car had the M3 rear subframe bushings done and this fixed the up and down bounciness but the car had insane side to side flex when accelerating onto a highway ramp or any scenario of that sort. Does anyone know what fixes this?

What is your alignment setting?

Within stock spec... cant say exact numbers... would this make that much of a difference? This car seems all over the place in the rear on hard acceleration.

PrematureApex · 05-13-2016, 07:38 AM

Same issues here, made a thread about it. Had 25 people chime in that it's the alignment.

I've run everything from 1/16" to 1/4" of rear toe. It it absolutely not alignment related. There's a large amount of flex and/or dynamic toe change going on back there. Feels like a rubber band winding up and releasing at times.

I bought some Whiteline poly bushings for both the toe and trailing arms...being dragging my feet installing...but I will soon.

I'll let you know.

05-11-2016, 03:30 AM	#1
ASAP Major General 10156 Rep 8,625 Posts Drives: '23 X3 M40i Join Date: Sep 2012 Location: FL iTrader: (0)	135i Rear Toe Arms Does anyone have experience with any upgraded rear toe arms? One issue that is imho near tragic on the 135i, is side to side deflection / rear end flex on hard acceleration... the car literally bounces side to side. My car had the M3 rear subframe bushings done and this fixed the up and down bounciness but the car had insane side to side flex when accelerating onto a highway ramp or any scenario of that sort. Does anyone know what fixes this? __________________ 2 x N54 -> 1 x N55 -> 1 x S55-> 1 x B58
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05-11-2016, 05:04 AM	#2
titium Major 327 Rep 960 Posts Drives: 2009 BMW 135i Join Date: Jun 2015 Location: Sydney iTrader: (0)	Megan racing toe arms and m3 guide rods.
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05-11-2016, 07:41 AM	#3
tuj First Lieutenant 50 Rep 379 Posts Drives: '13 135i Join Date: May 2013 Location: Stamford, CT iTrader: (0)	I'm no expert, but it would seem to me like the issue is the bushings in play here, not the arms themselves. I would think switching to poly bushings or even better, spherical bushings, would probably help a lot. __________________ Living the 1-life since 2013.
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05-11-2016, 08:15 AM	#5
tuj First Lieutenant 50 Rep 379 Posts Drives: '13 135i Join Date: May 2013 Location: Stamford, CT iTrader: (0)	What are you alignment specs? __________________ Living the 1-life since 2013.
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05-11-2016, 08:33 AM	#8
tuj First Lieutenant 50 Rep 379 Posts Drives: '13 135i Join Date: May 2013 Location: Stamford, CT iTrader: (0)	I dunno, this sounds like it could be an out-of-alignment setup or perhaps a bent rear suspension arm??? I have my car bone stock, and I get instability in the rear accelerating out of slow corners at the track. It's not that bad, it's just slower than it should be. How are you determining you have side-to-side flex in the RSF? __________________ Living the 1-life since 2013.
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05-11-2016, 11:23 AM	#12
tuj First Lieutenant 50 Rep 379 Posts Drives: '13 135i Join Date: May 2013 Location: Stamford, CT iTrader: (0)	How many miles on the car? I'm thinking perhaps worn bushings? (not RSFB but the other bushings) __________________ Living the 1-life since 2013.
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05-13-2016, 07:38 AM	#22
PrematureApex Colonel 840 Rep 2,402 Posts Drives: N55 X1, N54 135, s54 m3 Join Date: Jan 2008 Location: Philadelphia iTrader: (0)	Same issues here, made a thread about it. Had 25 people chime in that it's the alignment. I've run everything from 1/16" to 1/4" of rear toe. It it absolutely not alignment related. There's a large amount of flex and/or dynamic toe change going on back there. Feels like a rubber band winding up and releasing at times. I bought some Whiteline poly bushings for both the toe and trailing arms...being dragging my feet installing...but I will soon. I'll let you know. __________________ '02 S54 M3 (500/500 GC/Koni) '08 N54 135 (JB4, DCI, BMW PS/Bilstein B6s, H&R M3 FSB, Strongflex FCABs) '14 N55 X1 (JB4, BMS DP, BMS Intake, Alpina TCU reflash, H&R Sports, Bilstein B6s, E93 M3 RSB, Strongflex FCABs, baby seat) '08 N54 535xi touring (Bilstein B6s, Downpipes, MHD tune, baby seat)
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