Thuds and bangs over small bumps

dancing__narwhal · 07-16-2017, 04:00 PM

Ok I've had my my e90 328i LCI for about 8k miles and it had 53k miles on the odometer now. The (non-sport) suspension is stock and all original including style 285s on fairly new Conti run-flats. Only modifications are 5mm front/12mm rear spacers and new Meyle HD front tension arms.

Ever since I got the car I've felt like it takes bumps really hard with thuds and bangs. The weird thing is that large bumps (e.g. speed bumps) are fine. It's the small bumps in the road that I hit at 20+ mph that make a big thud.

It doesn't feel like I'm hitting bump stops as the bumps are not large enough. I've also checked for rubbing from the wheel spacers and I'm certain they are not rubbing.

The only thing I can guess is maybe the springs/shocks are going bad and therefore not absorbing the small/sharp impacts the way they should. I would be surprised if that was the case at only 50k miles though.

I'm used to cars with stiff suspension as I drove a GTI before this and it was bumpy but it didn't have the same bangs and thuds. Is it normal to for this car to take small bumps hard? If not, any advice on what might be the issue?

FWIW, it sort of feels like the thuds are coming from the rear axle, though it's really hard to tell for sure...

Phil325i · 07-17-2017, 03:09 AM

Get the car up on ramps and use a pry bar to test the health of your bushes (there are a lot of them on the rear of an E90).

Barefoot-335is · 07-17-2017, 06:00 AM

Stock Dampers are known to be shot by 50k miles.
When I did my 08 sedan at 54k miles, all 4 shocks/struts were blown.
I'm getting ready to do my '12 335is now, it is at 61k.

dancing__narwhal · 07-17-2017, 08:34 AM

Quote:

Originally Posted by Phil325i

Get the car up on ramps and use a pry bar to test the health of your bushes (there are a lot of them on the rear of an E90).

Any in particular that I should look at? How would I know if they are bad?

Phil325i · 07-17-2017, 10:09 AM

Quote:

Originally Posted by dgaultiere

Any in particular that I should look at? How would I know if they are bad?

These might help you. Not precisely for an E9* but the similar...

AoS810 · 07-17-2017, 12:42 PM

Could it be the run flat tires? I've never had experience with the Continental runflats, but when I changed from my factory Bridgestone runflats to Continental DW the difference in ride quality was huge (didn't feel every bump in the road) with my stock sport suspension.

I also had a similar experience where there was one part of the 57 North around Diamond Bar, CA that had a tiny little bump where every time I drove over it I could feel it jolt the entire car, after switching to the DWs that went away.

07-16-2017, 04:00 PM	#1
dancing__narwhal First Lieutenant 142 Rep 337 Posts Drives: 2024 m340ix Join Date: Nov 2016 Location: Santa Barbara, CA iTrader: (0)	Thuds and bangs over small bumps Ok I've had my my e90 328i LCI for about 8k miles and it had 53k miles on the odometer now. The (non-sport) suspension is stock and all original including style 285s on fairly new Conti run-flats. Only modifications are 5mm front/12mm rear spacers and new Meyle HD front tension arms. Ever since I got the car I've felt like it takes bumps really hard with thuds and bangs. The weird thing is that large bumps (e.g. speed bumps) are fine. It's the small bumps in the road that I hit at 20+ mph that make a big thud. It doesn't feel like I'm hitting bump stops as the bumps are not large enough. I've also checked for rubbing from the wheel spacers and I'm certain they are not rubbing. The only thing I can guess is maybe the springs/shocks are going bad and therefore not absorbing the small/sharp impacts the way they should. I would be surprised if that was the case at only 50k miles though. I'm used to cars with stiff suspension as I drove a GTI before this and it was bumpy but it didn't have the same bangs and thuds. Is it normal to for this car to take small bumps hard? If not, any advice on what might be the issue? FWIW, it sort of feels like the thuds are coming from the rear axle, though it's really hard to tell for sure...
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07-17-2017, 03:09 AM	#2
Phil325i Brigadier General 616 Rep 3,194 Posts Drives: E92 325i MSport Coupe Join Date: Apr 2012 Location: UK South East iTrader: (1) Garage List 2009 BMW 325i Coupe [6.00]	Get the car up on ramps and use a pry bar to test the health of your bushes (there are a lot of them on the rear of an E90). __________________ E92 pre-LCI 325i - Ohlins R&T; H&R spacers; M3 strut brace; Swift thrust sheets; 3 x chassis braces; diff brace; N53 V-brace; 034 subframe inserts; BMS clutch stop; BMS CDV; RE g/box mounts; Delrin shift bushes; Saikoumichi OCC; Cyba scoops; BMW Perf Exhaust; HEL s/steel brake hoses; M3 rear spoiler; Recaro Sportster CSs; M3 white dash LEDs; LED Angels; LED side repeaters; BMW Perf black grille; CSL reps; SSDD carbon diffuser; Monster Wrap black roof/clear front
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07-17-2017, 06:00 AM	#3
Barefoot-335is First Lieutenant 63 Rep 307 Posts Drives: 2012 335is Coupe Join Date: Aug 2010 Location: Barefoot Beach iTrader: (0)	Stock Dampers are known to be shot by 50k miles. When I did my 08 sedan at 54k miles, all 4 shocks/struts were blown. I'm getting ready to do my '12 335is now, it is at 61k.
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07-17-2017, 12:42 PM	#6
AoS810 Lieutenant 97 Rep 414 Posts Drives: 2008 E90 N51, 2011 E91 N52 Join Date: Oct 2009 Location: Los Angeles, CA iTrader: (6)	Could it be the run flat tires? I've never had experience with the Continental runflats, but when I changed from my factory Bridgestone runflats to Continental DW the difference in ride quality was huge (didn't feel every bump in the road) with my stock sport suspension. I also had a similar experience where there was one part of the 57 North around Diamond Bar, CA that had a tiny little bump where every time I drove over it I could feel it jolt the entire car, after switching to the DWs that went away.
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