[goguryeo1]

hi all,

2022 M4 Comp Xdrive (1.5 yeras old)- I am experiencing a clunking/thumping sensation in the front left wheel when making slow full turns out of a parked position, mostly when backing out from 3 o'clock to 6 o'clock. It's steadily getting worse and alarms me and anyone around. took it to the dealership who, after days of testing, said they don't know what the issue is and i'm taking it in again in a few days when the BMW engineer makes a monthly visit.

i see several posts about clunking or thumping on bumps and such but i don't know if i'm used to whatever feel or sound because this is my first car with sport suspension. i just know when it comes to making full turns and ONLY on the left which is making me nervous.

any insights? greatly appreciate it

note: i did replace the brake pads

[SwankPeRFection]

Is it as you’re rolling or can you duplicate it while stationary and going full lock to lock?

[Needsdecaf]

Ackermann Effect

https://www.mcgrathautoblog.com/auto...ette-stingray/

For some reason the search is sucking. But this is at least the 4th thread I've posted this on in the last 6 months. I don't blame you for not finding it because I can't even get clunk to come up in a search.

it's entirely normal.

[Znomorph4theWin]

Ackermann effect.

And it’s normal with cars with aggressive steering geometry…like the M3.

My RS5 had it too.

[Needsdecaf]

Originally Posted by Znomorph4theWin

Ackermann effect.

And it’s normal with cars with aggressive steering geometry…like the M3.

My RS5 had it too.

Yup, both my 911's had it. Even the RWD, manual transmission, mechanical LSD one. It's especially bad in the cold because the tires deform less.

On Rennlist, someone likened it to driving over acorns. A bit of a "hop" with an associated "pop". Every fall, all the new owners on the 911 forum started posting about it and guys would say "yup, here come the acorns!".

Definitely a bit unnerving if you've never owned a car with an aggressively designed suspension.

[Znomorph4theWin]

Originally Posted by Needsdecaf

Yup, both my 911's had it. Even the RWD, manual transmission, mechanical LSD one. It's especially bad in the cold because the tires deform less.

On Rennlist, someone likened it to driving over acorns. A bit of a "hop" with an associated "pop". Every fall, all the new owners on the 911 forum started posting about it and guys would say "yup, here come the acorns!".

Definitely a bit unnerving if you've never owned a car with an aggressively designed suspension.

Excellent point about cold temperatures. I forgot to mention that in my reply. It is definitely more noticeable at full steering lock on cold payment. The sensation of running over acorns is a top notch description!

[Needsdecaf]

Originally Posted by Znomorph4theWin

Excellent point about cold temperatures. I forgot to mention that in my reply. It is definitely more noticeable at full steering lock on cold payment. The sensation of running over acorns is a top notch description!

Yeah, it is a good one. Cant take credit for it but it helped me associate it vs something else’s I try to use it hoping it will help.

[goguryeo1]

thank you so much everyone. i had gathered a bunch of different parts from other "clunk-related" posts when going low speeds and nothing about full turn so i'm glad i posted here and got some sure answers.

but to confirm Ackermann Effect - is it normal to only hear it on the left side? it's when i back out of a parking spot in full turn in a V-shape (3:00 to 6:00 then 9:00)

[Curious41]

If you've ever taken off the metal plate on the bottom of your car make sure all the bolts are properly torqued. A shop had just impacted those bolts on a friend's car and he had clunking when turning the wheel. After I torqued all the bolts to spec the clunking disappeared.

[Ankarah]

Panamera 4s are the same - thought something was broken and took it to a dealership the first time it happened.

Part of the reason why I didn’t get the Xdrive.

[Needsdecaf]

Originally Posted by Ankarah

Panamera 4s are the same - thought something was broken and took it to a dealership the first time it happened.

Part of the reason why I didn’t get the Xdrive.

Has absolutely nothing to do with AWD. My RWD 991 did this really severely.