Harshness - M3 front arms, Bilstein B8, Performancr springs

juld0zer · 12-25-2016, 12:47 AM

Mods as per the title. When i drive over horizontal ridges in the road such as the bit before a bridge starts or entering driveways, the front end of the car feels/sounds like it's going to collapse. Is it the M3 arms with the stiffer bushing?

myles130i · 12-25-2016, 04:15 AM

Could your ARB (swaybar) bushes be on the way out?

John_01 · 12-25-2016, 04:19 AM

I think there is some added harshness from the M3 arms but its not like something is going to collapse. I am not sure about the Bilsteins though. Are you still using run-flats?

juld0zer · 12-25-2016, 07:36 AM

I'll look into the swaybar bushes. The endlinks appear to be weeping some grease but no binding can be felt. Is there an easy way to tell the swaybar bushes are toast? Pry downwards perhaps? Thing is, the same crashing sensation over the same horizontal dips was there with the stock M sport springs and shocks so it's disappointing that the new Bilsteins and BMW Performance springs failed to cure it. The car does have 137,000km now though..

Yes, on runflats still but ive set them to the lowest placard pressures with little change im harshness. S001 on the front and RE050A on the rear - originally the other way around but i moved the stiffer RE050A to the rear to test. Im running 245/35-18 all round, sorry i forgot to mention i have 10mm spacers on the front aswell as camber plates but the crashing was present before when it was 100% stock with stock size tyres. I was thoroughly convinced it was aged/worn shocks...

Suhb · 12-25-2016, 12:55 PM

Run flats feel like riding on stone wheels. Remember that BMW engineered these cars with run flats in mind. When you start stiffening things up, ditch the run flats next.

juld0zer · 12-25-2016, 08:23 PM

Just checked the swaybar bushes - there's unfortunately no slop there, no split rubber or anything. Instead i found the lower steering shaft vibrates when i thump the wheel towards the centre of the car (the part that collapses in an accident and joins the column to the rack with a universal joint at each end). This could explain why one wheel hitting a pothole doesnt shatter the interior but hitting a horizontal bump with both wheels at the same time causes the crashing feeling.

juld0zer · 01-09-2017, 07:42 PM

Just to update this thread: I've resolved the issue.
Cause: Inner ball joint of M3 lower control arm which replaced the rubber bushing of the stock arm. Nothing wrong with the ball joint itself, it just transmits too much impact to the cabin for my needs. I drove a 1M today for comparison's sake and it is similarly communicative of sharp bumps.

Replaced with new Lemforder arms as the original ones showed wear in the rubber (132k km). Lost a bit of the rigid front end feel but gained more confidence in corners despite less camber and less rigidity. It actually feels less vague now?

12-25-2016, 12:47 AM	#1
juld0zer Lieutenant Colonel 480 Rep 1,600 Posts Drives: Prev 135i 7DCT, Now 130i 6sp Join Date: Jul 2016 Location: 2153 iTrader: (0)	Harshness - M3 front arms, Bilstein B8, Performancr springs Mods as per the title. When i drive over horizontal ridges in the road such as the bit before a bridge starts or entering driveways, the front end of the car feels/sounds like it's going to collapse. Is it the M3 arms with the stiffer bushing?
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12-25-2016, 04:15 AM	#2
myles130i Registered 0 Rep 3 Posts Drives: United Kingdom Join Date: May 2016 Location: The South iTrader: (0)	Could your ARB (swaybar) bushes be on the way out?
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12-25-2016, 04:19 AM	#3
John_01 Colonel 232 Rep 2,643 Posts Drives: E90 325i, E82 135i Join Date: Mar 2009 Location: Sydney, Australia iTrader: (0)	I think there is some added harshness from the M3 arms but its not like something is going to collapse. I am not sure about the Bilsteins though. Are you still using run-flats?
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12-25-2016, 07:36 AM	#4
juld0zer Lieutenant Colonel 480 Rep 1,600 Posts Drives: Prev 135i 7DCT, Now 130i 6sp Join Date: Jul 2016 Location: 2153 iTrader: (0)	I'll look into the swaybar bushes. The endlinks appear to be weeping some grease but no binding can be felt. Is there an easy way to tell the swaybar bushes are toast? Pry downwards perhaps? Thing is, the same crashing sensation over the same horizontal dips was there with the stock M sport springs and shocks so it's disappointing that the new Bilsteins and BMW Performance springs failed to cure it. The car does have 137,000km now though.. Yes, on runflats still but ive set them to the lowest placard pressures with little change im harshness. S001 on the front and RE050A on the rear - originally the other way around but i moved the stiffer RE050A to the rear to test. Im running 245/35-18 all round, sorry i forgot to mention i have 10mm spacers on the front aswell as camber plates but the crashing was present before when it was 100% stock with stock size tyres. I was thoroughly convinced it was aged/worn shocks...
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12-25-2016, 12:55 PM	#5
Suhb First Lieutenant 119 Rep 377 Posts Drives: 2010 128i Coupe 6-Speed Join Date: Dec 2012 Location: PA iTrader: (3)	Run flats feel like riding on stone wheels. Remember that BMW engineered these cars with run flats in mind. When you start stiffening things up, ditch the run flats next. __________________
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12-25-2016, 08:23 PM	#6
juld0zer Lieutenant Colonel 480 Rep 1,600 Posts Drives: Prev 135i 7DCT, Now 130i 6sp Join Date: Jul 2016 Location: 2153 iTrader: (0)	Just checked the swaybar bushes - there's unfortunately no slop there, no split rubber or anything. Instead i found the lower steering shaft vibrates when i thump the wheel towards the centre of the car (the part that collapses in an accident and joins the column to the rack with a universal joint at each end). This could explain why one wheel hitting a pothole doesnt shatter the interior but hitting a horizontal bump with both wheels at the same time causes the crashing feeling.
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01-09-2017, 07:42 PM	#7
juld0zer Lieutenant Colonel 480 Rep 1,600 Posts Drives: Prev 135i 7DCT, Now 130i 6sp Join Date: Jul 2016 Location: 2153 iTrader: (0)	Just to update this thread: I've resolved the issue. Cause: Inner ball joint of M3 lower control arm which replaced the rubber bushing of the stock arm. Nothing wrong with the ball joint itself, it just transmits too much impact to the cabin for my needs. I drove a 1M today for comparison's sake and it is similarly communicative of sharp bumps. Replaced with new Lemforder arms as the original ones showed wear in the rubber (132k km). Lost a bit of the rigid front end feel but gained more confidence in corners despite less camber and less rigidity. It actually feels less vague now?
	Appreciate 0 Quote