Issue with 992
#1
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Hope everyone is having a great Christmas weekend.
I have observed on my GTS that when I turn my wheel right or left to max to reverse or move forward, car appears to skip/jump at front wheel. I’m not sure if I’m able to explain this well or not. It’s just a feel in steering. I have RAS. Only 2k miles. All road, no track. Is it normal and what’s the remedy.
thank you
I have observed on my GTS that when I turn my wheel right or left to max to reverse or move forward, car appears to skip/jump at front wheel. I’m not sure if I’m able to explain this well or not. It’s just a feel in steering. I have RAS. Only 2k miles. All road, no track. Is it normal and what’s the remedy.
thank you
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doug_999 (12-26-2022)
#4
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This has been a common "feature" of just about every Porsche Sports car in the last 10-15 years... My 08 Cayman S, 2012 991.1 and current 992 have all done this... it is actually something that Porsche kind of does on purpose and was explained to me once, but not totally sure what the reason was. Something to do with the tires and power steering etc... Im not going to pretend I remember lol but it is absolutely normal.
#5
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I have observed more pronounced in clod weather like front wheel losing grip intermittently and less conspicuous when tires are little warm.
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Tanqueray86 (12-26-2022)
#7
Instructor
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This is sometimes called the Ackerman effect. Outside tire turns more in a turn and causes inside tire to skip.
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#8
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Thank you all.
#9
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Hope everyone is having a great Christmas weekend.
I have observed on my GTS that when I turn my wheel right or left to max to reverse or move forward, car appears to skip/jump at front wheel. I’m not sure if I’m able to explain this well or not. It’s just a feel in steering. I have RAS. Only 2k miles. All road, no track. Is it normal and what’s the remedy.
thank you
I have observed on my GTS that when I turn my wheel right or left to max to reverse or move forward, car appears to skip/jump at front wheel. I’m not sure if I’m able to explain this well or not. It’s just a feel in steering. I have RAS. Only 2k miles. All road, no track. Is it normal and what’s the remedy.
thank you
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RXP. (12-26-2022)
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BadlyDrawnBoy (12-25-2022),
Tanqueray86 (12-26-2022)
#11
Burning Brakes
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Some tires do it more than others. Less of an issue with the 19s FWIW.
#12
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Will go away once you put winter tires on. It’s a known phenomenon with all cars, it’s more prominent in sports cars. It is called the Ackerman effect which refers to the steering geometry of a vehicle, and how it can affect the handling and stability of the vehicle when turning. The Ackerman effect is named after German engineer Karl Friedrich Ackerman, who first described the phenomenon in the early 19th century.
In a vehicle with conventional steering geometry, the front wheels are angled outward from the centerline of the vehicle. When the vehicle is turning, the inner wheel has to travel a shorter distance than the outer wheel. To achieve this, the front wheels are angled differently, with the inner wheel pointed more sharply and the outer wheel pointed less sharply. This is known as the Ackerman steering geometry.
The Ackerman effect can affect the handling and stability of a vehicle when turning, particularly at high speeds or when the road surface is slippery. If the Ackerman geometry is not properly adjusted, it can cause the vehicle to understeer (fail to turn as sharply as the driver intends) or oversteer (turn too sharply), which can lead to a loss of control. In order to ensure proper handling and stability, it is important to maintain the correct Ackerman geometry on a vehicle.
youtu.be/RSChYAUlnGg
In a vehicle with conventional steering geometry, the front wheels are angled outward from the centerline of the vehicle. When the vehicle is turning, the inner wheel has to travel a shorter distance than the outer wheel. To achieve this, the front wheels are angled differently, with the inner wheel pointed more sharply and the outer wheel pointed less sharply. This is known as the Ackerman steering geometry.
The Ackerman effect can affect the handling and stability of a vehicle when turning, particularly at high speeds or when the road surface is slippery. If the Ackerman geometry is not properly adjusted, it can cause the vehicle to understeer (fail to turn as sharply as the driver intends) or oversteer (turn too sharply), which can lead to a loss of control. In order to ensure proper handling and stability, it is important to maintain the correct Ackerman geometry on a vehicle.
youtu.be/RSChYAUlnGg
Last edited by Z911; 12-25-2022 at 11:26 PM.
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woobiee (12-25-2022)
#13
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Will go away once you put winter tires on. It’s a known phenomenon with all cars, it’s more prominent in sports cars. It is called the Ackerman effect refers to the steering geometry of a vehicle, and how it can affect the handling and stability of the vehicle when turning. The Ackerman effect is named after German engineer Karl Friedrich Ackerman, who first described the phenomenon in the early 19th century.
In a vehicle with conventional steering geometry, the front wheels are angled outward from the centerline of the vehicle. When the vehicle is turning, the inner wheel has to travel a shorter distance than the outer wheel. To achieve this, the front wheels are angled differently, with the inner wheel pointed more sharply and the outer wheel pointed less sharply. This is known as the Ackerman steering geometry.
The Ackerman effect can affect the handling and stability of a vehicle when turning, particularly at high speeds or when the road surface is slippery. If the Ackerman geometry is not properly adjusted, it can cause the vehicle to understeer (fail to turn as sharply as the driver intends) or oversteer (turn too sharply), which can lead to a loss of control. In order to ensure proper handling and stability, it is important to maintain the correct Ackerman geometry on a vehicle.
In a vehicle with conventional steering geometry, the front wheels are angled outward from the centerline of the vehicle. When the vehicle is turning, the inner wheel has to travel a shorter distance than the outer wheel. To achieve this, the front wheels are angled differently, with the inner wheel pointed more sharply and the outer wheel pointed less sharply. This is known as the Ackerman steering geometry.
The Ackerman effect can affect the handling and stability of a vehicle when turning, particularly at high speeds or when the road surface is slippery. If the Ackerman geometry is not properly adjusted, it can cause the vehicle to understeer (fail to turn as sharply as the driver intends) or oversteer (turn too sharply), which can lead to a loss of control. In order to ensure proper handling and stability, it is important to maintain the correct Ackerman geometry on a vehicle.
#14
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Thanks, great info. May I ask if this is more pronounced in non front engine cars like Porsche sports cars because of less weight on top of the front wheels? I've had BMWs for quite a while, F82, E46, etc, and this has never happened to them before. My 911 has been the first car that I've experienced this phenomenon.
Last edited by Z911; 12-25-2022 at 11:39 PM.
#15
Instructor
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Having just jumped from a C4S into a GTS4 I can say this effect is greater on the latter.
From just looking I am absolutely sure the GTS4 runs much more negative camber on the front which must increase the tyre scrubbing in a low speed turn.
The only other difference is tyres are now P-Zeros compared to Goodyears on the older car (yes I lost the tyre lottery this time around sadly)
From just looking I am absolutely sure the GTS4 runs much more negative camber on the front which must increase the tyre scrubbing in a low speed turn.
The only other difference is tyres are now P-Zeros compared to Goodyears on the older car (yes I lost the tyre lottery this time around sadly)