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Wondering if this is normal

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Old Oct 9, 2018 | 11:01 AM
  #1  
Spartanlol's Avatar
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Default Wondering if this is normal

Had my 2014 GS350 for just about a year now. Love the car.
I noticed when I pull in or out of parking spots when my steering wheel is turned almost all the way sometimes I will feel a bump. Almost as if the car went over a small bump or if the tires were catching on something.
I asked about this during maintenance and they looked into it but didn't see anything abnormal. This is something that has been happening since day 1 I got the car.
It's not annoying or anything, I just want to make sure I'm not damaging anything.

Other thing is feeling the car change gears at slower speeds (30-40 MPH). Sometimes going around those speeds my body can actually feel the little "bump" or so which is accompanied by the bump in the needle on the tachometer.
Alternatively, I notice going at slow speeds going downhill and gently hitting the breaks will result in a noticeable "bump" as apparently the car downshifts and I will hear a sound from the engine.
These issues I've only started noticing recently but my commute also changed recently. Went from a short easy 6 minute ride to work to 50 minutes. It's possible I've only started noticing these things now.

Anyways, just wondering if this is pretty typical or may be a problem. I never have any engine lights pop up, always take it for scheduled maintenance when it's time. My car knowledge is somewhat limited.
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Old Oct 9, 2018 | 11:39 AM
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Originally Posted by Spartanlol
Had my 2014 GS350 for just about a year now. Love the car.
I noticed when I pull in or out of parking spots when my steering wheel is turned almost all the way sometimes I will feel a bump. Almost as if the car went over a small bump or if the tires were catching on something.
I asked about this during maintenance and they looked into it but didn't see anything abnormal. This is something that has been happening since day 1 I got the car.
It's not annoying or anything, I just want to make sure I'm not damaging anything.
Normal. Due to Ackermann steering geometry. You'll find similar behavior on Porsches and many other sportier-natured cars.
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Old Oct 9, 2018 | 11:51 AM
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I have noticed this too, figured it was normal and because of AWD or something. Good to know it is because of Ackermann steering geometry, I'll have to look that up.
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Old Oct 9, 2018 | 11:54 AM
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Originally Posted by signdetres
Normal. Due to Ackermann steering geometry. You'll find similar behavior on Porsches and many other sportier-natured cars.
Thanks! Glad I asked.
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Old Oct 9, 2018 | 12:02 PM
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Read about Ackermann Steering Geometry and also about Scrub Radius and Squirm.

When a car with a tight suspension and wide tires makes a small radius turn at a slow speed, one of the front tires can slip, jump or jerk.



You'll find it slips/skips easier when you drive over a surface that has both dry and wet patches - with the wet surface making it slip more, or when turning sharply on a surface where there are painted lines (e.g. parking lot) because the paint eliminates the friction of the rough surface texture.

Last edited by bclexus; Oct 9, 2018 at 01:51 PM.
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Old Oct 9, 2018 | 01:05 PM
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My RC does this too.
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Old Oct 9, 2018 | 01:47 PM
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I noticed this as well on my GS350 AWD. It does it even at 90 degree turn at low speeds especially when there's a slippery patch of surface.
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