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S63 Amg Eperformance knocking sound on tight turns
I bought a dealer showroom test car having 2000 km from the dealer from another country where I reside. I drove it just 100km yet. I realized it was making a knocking sound on tight turns at low speed, or when I left the parking, etc. It feels like the front tires are sliding, making vibrations. Is it because it has a sports suspension? It is below 7 Celsius, and summer tyers are on. Should I check it at the service?
I am also waiting for the 21-inch Amg rims to be delivered. Right now, it has 20-inch Amg rims. Do you have any specific suggestions for winter and summer tires for this car?
Currently it has 255/45 ZR 20 (105Y) Front and 285/40 ZR 20 (108Y) back. Right now, it has these rims.
I am going to change it with this.
2025 AMG G 63 SUV /// 2025 AMG GT 63 S E Performance 4 Door Coupé
Does it do this all the time even after a journey that warms up all the components, including the 4Matic transfer case and front diff? The clunking could be cold diff oil not allowing proper distance between cogs because cold oil doesn’t “move out of the way” as well. All my Audis did this when I’d turn full lock with it cold outside and I hadn’t driven anywhere yet. My R8 would literally feel like it was skipping a diff clog! Stopped doing it literally after 2-3 km of driving.
Last edited by G63GT63SE; Apr 5, 2025 at 03:50 PM.
Although I haven’t had any experience with the 21 inch wheels, many others here have, and I would avoid them. I’d keep your 20 inch rims. Sorry for the unsolicited advice but I might do a forum search as many members have experienced multiple blowouts with the 21 inchers, especially with the stock Pirelli’s.
Probably Ackerman effect; video below. In a low speed, tight turn, your tires all have a different turn radius and velocity. Get tires wide enough, temperature low enough, and the differences can't be accounted for with differentials and tire scrub, and the hop you feel is the correction. Super common with Corvette, Porsche, and others. Some call it the Acorn effect, a search for either term will give you a lot of hits. And calm your nerves; you're just encountering a downside to a sporting setup, you get used to it.
When I had my E63 with summer tires, I had a similar issue on very cold mornings when the tires were cold. The cold tires would make sound/feel like they were skipping along. This would only last until the tires warmed up, just a couple of miles. Is that what you are experiencing?
you can't drive summer tires without expecting this under 40°F sometimes. Additionally, when you do have wheel hop like this, it also indicates you'll have less performance: braking and handling with the tires and this is a safety issue.
Last edited by PeterUbers; Apr 8, 2025 at 10:10 AM.
As said above. It's the Ackermann effect and very common on performance cars. Performance cars typically don't use perfect Ackermann geometry to improve handling, so you get wheel skip on tight turns, especially when the tires are cold and have low grip as in your case with summer tires below 7 Celsius. It's also typically more pronounced with AWD. People refer to it as crabbing. You see lots of posts about this in the SUV and other sections. Common complaint on the C43 and GLC models etc.
Don't know what tires the S63 comes with from the factory, but the performance tire to get these days is the new Michelin Pilot Sport S 5, which AMG now uses on all their latest models. Not sure if the S63 already got it. The next best is the PS4S. If you want the perfect setup, get the MO1 marked variants. Those are specifically tuned for AMG. Some others are great, too. I currently have the BMW marked PS4S on my AMG. Noticeable improvement over the standard aftermarket replacement PS4S. The PS4S is a two compound tire, but these car manufacturer marked variants use the different compounds in different places and have different internal construction to optimize for how they want the car to drive. Below are a couple of videos to show what this means.
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Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
