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Discussion Starter · #1 ·
I've noticed that at slow speeds and at full lock. I get a steering judder. Is this due to the Ackerman principle or will there be a fault with the steering? I used to have a Porsche 911 that did the same thing, but they said it was because of the wide wheels.

Cheers Fred
 

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I have the same. Seems to be more noticeable with cold temperatures and maybe older harder tires (Dallas summers will harden them). I think it's normal. Ackermann principle seems a good explanation.
 

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I have the same. Seems to be more noticeable with cold temperatures and maybe older harder tires (Dallas summers will harden them). I think it's normal. Ackermann principle seems a good explanation.
Same here. I have to make a very sharp and very slow blind left turn in the garage at my office and it feels like the car is skipping sideways when I am doing it. As soon as I come off the steering lock, it stops. Does not appear to cause any other problems.
 

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What do you mean by judder? You mean the sense that your rolling over a bump or something in full lock turn (like during a U-turn)?
 

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Same here... I talked to my dealer in August 2012 and the tech told me 'works as designed' and added... it would be the same with any long car with Karma's ability to take such relatively small circles... provided they have the same tires
 

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I get that too when my turning radius is tight, typically a full uturn. It feels like extra resistance - I think it's due to tire size steering radius ..
 

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I get that too when my turning radius is tight, typically a full uturn. It feels like extra resistance - I think it's due to tire size steering radius ..
Can you describe the sensation?
 

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Can you describe the sensation?
it feels like your running over somthing, a tugging feel. Another way to descirbe it is a sort of skipping effect, grip, tug, grip -- it's not pleasent and feels like it was not properly designed and it's defintly not every smooth - never felt it before in a car. I'm told it is the lenght of the car, tire size and speed one is traveling.
 

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They all do it. I've heard that changing the tires to a different brand may help, though I really only know of two cars that didn't stick with the factory tires after a change and I didn't check on the stuttering when I was in them.
 

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Is this not an effect of rear wheel drive? The front tires must push the front of the car side ways but the rear tires are pushing the car in a straight forward line. So the front tires are just skidding on the surface. It is worse on slippery surfaces such as garages.
On a front wheel drive car the front wheels actually pull the front of the car sideways.
 

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Is this not an effect of rear wheel drive? The front tires must push the front of the car side ways but the rear tires are pushing the car in a straight forward line. So the front tires are just skidding on the surface. It is worse on slippery surfaces such as garages.
On a front wheel drive car the front wheels actually pull the front of the car sideways.
Well, kind of. Mostly it's just the size (width) of the tires themselves, really.

Try an experiment. You'll look silly but should feel enlightened :D ...

Stand comfortably with both feet in line with each other, as if you're standing at a starting line. Then, slide your left foot forward one foot-length while turning it in an arc, as though you're a car turning left in a tight circle. Next, slide your right foot forward one foot-length (only one foot-length!) while making the same turn, which, since your feet are apart, is in a wider arc. Note that your right foot is now behind your left foot.

Slide your left foot one more foot-length forward in the arc, continuing the turn. Slide your right foot forward similarly. Now your right foot is even more behind your left one.

When you drive in a circle, your tires have to do the same thing: the side of the tire "towards" the turn (the left edge if turning left, right edge if turning right) moves in a tighter arc than the other side of the same tire. The wheel on the outside of the turn has to go much slower than the wheel on the inside of the turn, but the back wheels can do this due to the differential, and the front wheels can do it because they're not driven in the first place, so each one turns freely. But it's true not only of the wheel, but also of the tire itself: the "inside edge" wants to turn more RPMs than the "outside edge"—but this is impossible.

A skinny tire has less differential RPM rates on inside-vs-outside, and the less sharply you turn (in a bigger arc), the less "turn scrub" you apply to the tires.

Incidentally, this is also why you don't drive a locked, full-time 4WD drive system on dry pavement, only on slippery surfaces (mud, snow, sand, etc): the inside and outside wheels need to turn at different speeds whenever you go around any turns.
 

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Discussion Starter · #14 ·
I tried this in a bar last night, whilst doing the vroom vroom noise and steering n imaginery steering wheel. I am now in a mental hospital ward shouting "I was ony pretending to be a Fisker" - Any suggestions how I get out of here???:D:D:D

Fred
 

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Discussion Starter · #16 ·
Bit drastic NJ - I'll just tolerate the syeering judder instead!!

Fred
 

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I'm not sure this is the same thing but my front wheels rub against the front section of my fender wells every time I back-up with a slight turn in the wheels. Going froward, I only feel/hear it on sharp turns. Not sure if it is because the fenders have vents that face down and so they rub easier or what on the forward direction.
 

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Mines did the same until I checked the inside fender liner placement. It seems the push pins that hold them in place was not there correctly. Installed some new ones and that fixed the rubbing, although they the hard turning skipping is still there when turning hard left...
 
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