Full-Lock Slow-Speed Turning Strange Behavior
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2023 S500
Full-Lock Slow-Speed Turning Strange Behavior
Anyone else feel like the front wheels slip or catch for slow-speed full-lock turns? When I back out of my driveway and nearly lock turn while driving over the sloped curb, it feels like the front wheels slip or catch. It also happens on flat ground and while driving forward. It’s hard to explain, but it does not feel natural. I only notice while going very slowly.
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From: Costco
2023 S500
Nice. Never even heard of this issue before. I came into this car with enthusiasm and some pride in ownership. I don’t feel that way anymore. All I can is this: that Alabama plant has some major quality control issues and MB has some really lame engineers and development managers.
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'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
It's a characteristic of wide tires. The wider the tread, the less the Ackerman Effect is able to compensate for turning angles.
In all turning tires, the outer tread blocks travel farther than the inners, and something slips a bit. Just like a locked differential makes the inner and outer tires fight each other.
When you release the tension by going over a curb, the tire will move.
Edit: Summer tires can be more prone to this at low temps.
In all turning tires, the outer tread blocks travel farther than the inners, and something slips a bit. Just like a locked differential makes the inner and outer tires fight each other.
When you release the tension by going over a curb, the tire will move.
Edit: Summer tires can be more prone to this at low temps.
Last edited by mikapen; Nov 4, 2022 at 09:41 PM.
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'13 GLK350 4matic,'10 C207,'15 GLA250,'07 Honda Odyssey, '18 GLE 43, '24 EQS 580
Anyone else feel like the front wheels slip or catch for slow-speed full-lock turns? When I back out of my driveway and nearly lock turn while driving over the sloped curb, it feels like the front wheels slip or catch. It also happens on flat ground and while driving forward. It’s hard to explain, but it does not feel natural. I only notice while going very slowly.
Last edited by shotgun_banjo; Nov 4, 2022 at 10:40 PM.
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From: SWFL
2024 GLE 450, 2009 SLK 300
Friend of mine had a similar problem with his AMG. Turned out he was using summer tires in Maryland in January. He continued to drive the car and ended up ruining the tires. Had chunks of rubber coming off the tires.
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Nice. Never even heard of this issue before. I came into this car with enthusiasm and some pride in ownership. I don’t feel that way anymore. All I can is this: that Alabama plant has some major quality control issues and MB has some really lame engineers and development managers.
No need to be disappointed with something that isn't a problem, just normal behavior you weren't aware of.
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From: Costco
2023 S500
I find it hard to believe it’s normal; I’ve never experienced anything like this before and I’ve owned countless AWD vehicles with “very wide tires.”
This is just another disappointing revelation about this thing. I’ve never owned a car that had this many annoying issues before. It’s really disappointing.
This is just another disappointing revelation about this thing. I’ve never owned a car that had this many annoying issues before. It’s really disappointing.
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Out Of Control!!
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From: unbegrenzt
2017 GLE350 4MATIC
Anyone else feel like the front wheels slip or catch for slow-speed full-lock turns? When I back out of my driveway and nearly lock turn while driving over the sloped curb, it feels like the front wheels slip or catch. It also happens on flat ground and while driving forward. It’s hard to explain, but it does not feel natural. I only notice while going very slowly.
GLC63 has it bad.
Other models/brands have it too. Nothing can fix it, but rather only mask it.
It’s “normal” in the sense it is built into the steering and suspension geometry chosen by MB. It can’t be undone, it is a fundamental aspect of the vehicle design. Unless aftermarket hubs, knuckles and control arms are used. i.e. a new front suspension.
Last edited by chassis; Nov 5, 2022 at 03:58 PM.
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From: Costco
2023 S500
Well, to call something that has “error” in its name normal leaves a lot to be desired. Again, this is the first I’ve heard of it or experienced it and I've owned AWD Audis and BMWs without this “error.”
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From: Boise
2024 GMC Canyon Denali..... 2018 Audi SQ5
It’s not an error but Physics. Geometry, turning radius, tires, temps all play a part. BMW want’s you back…it’s a far better POS. Life’s short get something that makes you happy.
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According to the Society of Automotive Engineers (SAE), it is called “error.”
https://www.jstor.org/stable/44470999
https://www.jstor.org/stable/44470999
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'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
Ackermann error.
GLC63 has it bad.
Other models/brands have it too. Nothing can fix it, but rather only mask it.
It’s “normal” in the sense it is built into the steering and suspension geometry chosen by MB. It can’t be undone, it is a fundamental aspect of the vehicle design. Unless aftermarket hubs, knuckles and control arms are used. i.e. a new front suspension.
GLC63 has it bad.
Other models/brands have it too. Nothing can fix it, but rather only mask it.
It’s “normal” in the sense it is built into the steering and suspension geometry chosen by MB. It can’t be undone, it is a fundamental aspect of the vehicle design. Unless aftermarket hubs, knuckles and control arms are used. i.e. a new front suspension.
The Ackerman(n) effect, as it refers to suspension geometry, isn't the issue. It's the 13" wide tires, which have their own inherent, internal Ackermann-like issues.
You can demonstrate this yourself by steering a naked tire across the floor. The wide tire must induce more slip to turn than a narrow tire.
If you don't have a tire available, use a milk carton, lay it on its side and again on its bottom, slide it around a "corner." There will be comparatively more slippage with the greater width on the countertop.
Perfect Ackermann front suspension geometry requires a fictional Zero Width tire.
The solution for the OP is to put bicycle tires on his car.
It's not the car, Mercedes, or those stupid engineers.
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From: Boise
2024 GMC Canyon Denali..... 2018 Audi SQ5
Factoids:
Ackerman is used in all regular cars and anti ackerman used in special cars like F1 cars and some sports cars. Effects on wheels. In ackerman front outer wheel have more load on it while cornering and in anti ackerman front inner wheel have more load on it while cornering.
Advantages. The intention of Ackermann geometry is to avoid the need for tires to slip sideways when following the path around a curve. The geometrical solution to this is for all wheels to have their axles arranged as radii of circles with a common centre point.
Ackerman is used in all regular cars and anti ackerman used in special cars like F1 cars and some sports cars. Effects on wheels. In ackerman front outer wheel have more load on it while cornering and in anti ackerman front inner wheel have more load on it while cornering.
Advantages. The intention of Ackermann geometry is to avoid the need for tires to slip sideways when following the path around a curve. The geometrical solution to this is for all wheels to have their axles arranged as radii of circles with a common centre point.
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'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
Take your newfound diagram and apply the lines to a single, wide tire.
Think about that and apply it to your OP.
You have experienced it on every car you've owned. Maybe not with the tires with as such high traction or width, but it's ALWAYS there. Period.
Stick with this forum. You'll "hear of" more things that are true as you participate.
Here's a picture of the energy you released by driving over a low friction surface with your sticky tires at full lock, as you described in you OP. Slip angles and the Ackerman effect. This is what's called "crabbing." Keep studying.
Last edited by mikapen; Nov 5, 2022 at 04:48 PM. Reason: crabbing
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From: Boise
2024 GMC Canyon Denali..... 2018 Audi SQ5
Good explanation Mike. Since I put the Michelin CrossClimate tires on our AUDI, the more aggressive tread enhanced the Ackerman effect so that there is a noticeable rumble at full lock. It was also there with the OEM Michelin Primacy Tour tires backing out of the garage when cold. I never thought to complain about it on the Audi Forum.
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According to this article, the steering dynamics can be designed to slip or not based on the geometry, or the steering angle of the inner and outer wheel (with respect to a slew of other parameters). This leads me to believe this condition is a conscience decision based in the angle differential, which is skewed more towards the Ackerman angle. I can only assume that since I’ve never experienced this or seen a post about it on BMW or Audi’s forum over the last 12 years, that they chose an angle that minimizes this vs MB.
http://ckw.phys.ncku.edu.tw/public/p...ing_Theroy.pdf
http://ckw.phys.ncku.edu.tw/public/p...ing_Theroy.pdf
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From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
According to this article, the steering dynamics can be designed to slip or not based on the geometry, or the steering angle of the inner and outer wheel (with respect to a slew of other parameters). This leads me to believe this condition is a conscience decision based in the angle differential, which is skewed more towards the Ackerman angle. I can only assume that since I’ve never experienced this or seen a post about it on BMW or Audi’s forum over the last 12 years, that they chose an angle that minimizes this vs MB.
http://ckw.phys.ncku.edu.tw/public/p...ing_Theroy.pdf
http://ckw.phys.ncku.edu.tw/public/p...ing_Theroy.pdf
To solve this in your own mind, take the diagrams that you find in your Ackerman research, and instead of applying them to an inner and outer tire, apply the diagrams to the inner and outer tire tread. You will find exact same effect on a tire, as you do with the front steering geometry in total.
Also notice that when those diagrams are presented, they are presented at the center line of the tire. The equation would be different if you use the inner line or outer line of the tire.
Try the example of trying to turn a wide tire while rolling it across the floor, compared to a bicycle tire. Then apply that experience to what you're seeing / feeling in real life as you research.
OTOH, maybe the BMW and Audi steering that you've been used to are too numb to feel tires.
You've moved up a notch, as has Mercedes with the V167.
Leapfrog.
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I’m sure the diameter of the tire plays a part of this equation. However, that is a factor I’m sure the MB engineers took into consideration when they designed everything.
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Ackermann error.
GLC63 has it bad.
Other models/brands have it too. Nothing can fix it, but rather only mask it.
It’s “normal” in the sense it is built into the steering and suspension geometry chosen by MB. It can’t be undone, it is a fundamental aspect of the vehicle design. Unless aftermarket hubs, knuckles and control arms are used. i.e. a new front suspension.
GLC63 has it bad.
Other models/brands have it too. Nothing can fix it, but rather only mask it.
It’s “normal” in the sense it is built into the steering and suspension geometry chosen by MB. It can’t be undone, it is a fundamental aspect of the vehicle design. Unless aftermarket hubs, knuckles and control arms are used. i.e. a new front suspension.
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'13 GLK350 4matic,'10 C207,'15 GLA250,'07 Honda Odyssey, '18 GLE 43, '24 EQS 580
I find it hard to believe it’s normal; I’ve never experienced anything like this before and I’ve owned countless AWD vehicles with “very wide tires.”
This is just another disappointing revelation about this thing. I’ve never owned a car that had this many annoying issues before. It’s really disappointing.
This is just another disappointing revelation about this thing. I’ve never owned a car that had this many annoying issues before. It’s really disappointing.
Last edited by shotgun_banjo; Nov 5, 2022 at 11:28 PM.
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From: Costco
2023 S500
I’m not going to sell this thing and take a gigantic loss. I already tried, and even though I put $10k down and paid MSRP, offers aren’t what they used to be a few months ago, coupled with the fact that I got an interest rate below 3%, which i can’t get now.
I’m stuck with this thing for at least a few more years.
I’m stuck with this thing for at least a few more years.
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From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
I’m not going to sell this thing and take a gigantic loss. I already tried, and even though I put $10k down and paid MSRP, offers aren’t what they used to be a few months ago, coupled with the fact that I got an interest rate below 3%, which i can’t get now.
I’m stuck with this thing for at least a few more years.
I’m stuck with this thing for at least a few more years.
Get the ones with the highest wear ratings, and the lowest traction rating that you can find. That should eliminate the problem, or at least reduce it a lot.
If you really want to have the best outcome for driveways, buy a set of 20 inchers with touring tires that you find in the Used forums. Seriously.
In the meantime, drive the heck out of it. You'll enjoy your car, and you'll hasten the new tires.
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AMG GTC Roadster, E63s Ed.1, M8 Comp. Coupe
This is very noticeable on our BMW M8 Competition coupe and the car is better for it when driving. Which is when it matters...
Same on our AMG's although it seems more apparent on AWD's.
Last edited by Wolfman; Nov 6, 2022 at 07:32 PM.
