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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Suspension | Brakes | Chassis > Bump Stops and Koni shock absorbers



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      09-27-2013, 03:04 AM   #1
Zokii-10
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Bump Stops and Koni shock absorbers

Not long ago i lowered my car and put 20" wheels on it, i changed the springs and the shock absorbers and the car dropped about 40mm in the rear and 50mm in the front however the person who was installing that cut the front bump stops and now when i go over pot holes it makes a really bad knocking sound and it is not good. I a wanting to change the bump stops and have read on forums saying that the M3 e36 front bump stops will be ok. Will that get rid of the noise that i am getting now?

Thanks in advance.
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      09-27-2013, 10:07 AM   #2
JYohay
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e36 bump stops on front and z4m on rear is what is recommended if i am not mistaken.
im on koni FSDs and Eibach springs, no knocking.
dont know if thats the issue.
could be a lookse top mount, sway bar, or evven bushings....
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      09-27-2013, 11:26 AM   #3
mike-y
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I'd check the top nuts first. it's common for them to loosen up if the guide support wasn't completely settled on the strut shaft during install.
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      09-27-2013, 02:15 PM   #4
critical05
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Although I have an XI, when I lowered using eibach springs with Koni struts, I cut my front bump stops as well. The ride was nice but on large bumps it felt like the suspension bottomed out and you would get a loud jarring thud (felt and heard). I did a lot of searching and thought it was the pothole explosion affect people were describing on their vehicle and something you had to live with.

After 6 months of this, I ended up swapping in the m3 bumpstops, it was so much better. What I assumed, there really isn't much suspension travel until the top of the strut body contacts the bump stops. When you cut the bumpstops, you lose the softer cushy side and your left with the really firm portion. When you go over a large bump, there isn't much to soften the blow and you get this hammering feeling/sound. With the shorter bumpstops, you have the cushy portion to absorb and gradually slow the suspension vs. hammering against the bumpstop.

It was worth it for me to swap them in.

Also the loss of sidewall makes for a harsher ride. I have two sets of tire/rim combos, both are 18" with the same tire size. One set is stretched and it rides way rougher.
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      09-29-2013, 12:13 AM   #5
Zokii-10
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Thanks heaps guy's!

I will look into the nuts, bushings and everything you have mentioned first before purchasing actual bump stops if they do not fix the problem. I will keep you guy's posted on how i go..
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