[Lotus99]

I was only doing like 20 MPH at night, when I felt this really hard bump. I got out after and saw unmarked potholes from construction that had been dug out from so many cars driving over them. They are maybe 3 to 4 inches deep at the center but not sharp at the edges - sort of bowl shaped. So I was surprised at the loudness of the clunk I heard and felt when I went over them. It felt like hitting a huge rock with the frame of the car...





I got out after and checked out my wheels, worried they'd be bent, but couldn't see anything. They had taken a good hit I suppose, because normally there's a small gap between the tire and the rim, and I could see the impression of the tire that was left on the rim.


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The car is driving fine, even on highway, not pulling to the left or right, or vibrating.


So here are my questions:

1. Is it possible for the wheels to have gone up into the wheel well so much so that the shocks compressed all the way to the max, and that's what I felt - them bottoming out? If so, any damage done possibly from this one time event?
2. Could the rims be damaged, other than what I can see visually at the edge, which seems ok? I have the wheel and tire insurance, so maybe I should get them to take them off and inspect, or am I being paranoid?

[noro]

If you aren't observing any differences in ride quality I wouldn't worry then.

[Kilgore Trout]

You've been a victim of the "Pothole explosions" phenomenon. Seems to afflict primarily those with ZSP.

http://www.bimmerfest.com/forums/sho...d.php?t=336867

I agree with Noro that you probably don't have a reason for concern.

[Lotus99]

Thanks a lot for the other link, I'll check it out. Sounds like some others have experienced the same thing...

I'm running on RFT's and have the sport package with 18's. It really sounded and FELT bad. Like it was the Dukes of Hazzard landing some huge jump!

Yea I did the same thing, took it to west end alignment, alignment was off but nothing was bent, bmw has pretty good bushings.

[jpsum]

my xi bottoms out all the time! That's just the way it is.

[E90330iS]

should be ok

[nicknaz]

it happens don't worry about it. if your car starts to pull to the side or you get a vibration get the alignment checked.

[Kilgore Trout]

For what it is worth, my non-sport E91 with 17" RFTs NEVER "bottoms out."

What confuses me about this is that the folk with ZSP and Xi both seem to have the problem, but the base supension does not.

The reason why this confuses me is that I thought the base suspension was lower to the ground than the Xi and, therefore, would be more prone to "bottoming out."

[jrave]

haven't had this myself, and I have the 19's (design 179 I think).

[Lotus99]

To clarify, the bottom of the car is not hitting anything (which I usually call bottoming out), which I have done when going over a crest in the road with a dip right after it very quickly.

It's the suspension that I was wondering whether it had bottomed out, as if the shocks compressed down all the way and that's what I had felt when they compressed to their limit...

[Payroll]

Originally Posted by Nick Nazareno

it happens don't worry about it. if your car starts to pull to the side or you get a vibration get the alignment checked.

+1. You're being paranoid - unless you notice anything strange, it's fine. My car bottoms out from time to time. That's what bump stops are for - they're made to withstand the all but the most severe impacts.

[HermesRider]

You should be alright. I too have done this a number of times and the only thing louder than the suspension explosion is the explitive that follows. To save my suspension and blood pressure I moved from cleveland to charlotte. Problem solved.

[Lotus99]

Wow. Pretty crappy design for sure. This was hardly what I'd call a pothole! I'd hate to feel a real one!

So what was it that I felt (and heard) exactly? Is it the suspension compressing to the max and transferring the impact thru to the cabin? Is it that our sport suspensions just don't have a lot of travel in them?

Or was it the wheel itself that hit the edge of the road given the low profile RFT's we run, and transferred that impact to the cabin?

[bernjee82]

Happened to me as well, e90 with zsp and rfts. Thrust angle was off after, took it to alignment and all is good for now.

[SteveC]

Imagine turning that dip inside out to make a speed bump and hitting that at 20 mph. From the suspension point of view its the same thing (entension/compression for a dip, comression/extension for a bump)

Clearly a speed bump that size hit at 20 mph would soak up all the suspension travel and have you hitting the bump stops.

If your wheel is still round, no vibration and no pulling, then its unlikely that any damage was done. You may want to have alignment checked or keep an eye on tyre wear patterns

[speedytobey]

you might want to check the inside rim of the wheels.

[JFU]

Ya I had that happen once going over an unmarked pothole in my 08 328xi.
It was literally the loudest thing i have ever heard. I thought I had torn my front fender or something and got out to check. Everything seems to be fine, along with alignment.

Co-incidentally, does anyone else notice an annoying creaking sound when they go over speed bumps? My car does that seemingly randomly. Some days its rlly quiet, other days it really sqeaks. (All over the same speed bumps)