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Posted

Since I got the car i've noticed that when I make a hard left or hard right turn it feels like the tires skip a beat, a little jerk, not a steady turn. This is only when the steering wheel is at a full left or full right. Casually driving I never notice this, it's usually when i'm making my way out of a tight spot like in a parking lot when I have to turn the car around. Any idea what this could be? Damaged tire(s)?


Posted
Since I got the car i've noticed that when I make a hard left or hard right turn it feels like the tires skip a beat, a little jerk, not a steady turn. This is only when the steering wheel is at a full left or full right. Casually driving I never notice this, it's usually when i'm making my way out of a tight spot like in a parking lot when I have to turn the car around. Any idea what this could be? Damaged tire(s)?

It is unlikely you're going fast enough in a tight spot for a parking space to be experiencing any degree of "understeer"...at least any that would be noticable.

I see you have the AWD, and what you are experiencing is most likely the wheel travel difference between the front wheel and the rear wheel. In any turn, the differential allocates the majority of power to the outside wheel. This is due to the fact that the outside wheel has a longer radius and a further distance to travel than the inside wheel. The differential simply see's this as the least resistance.

On your car, you have two differentials - front and rear. Since the rear wheels basically cut off the angle of the arc of the front wheel travel, the rear wheels are travelling a shorter distance than the front wheels. An exagerated (and somewhat incorrect) example of this is the hypotinuse of a triangle. More specifically, the rear outside wheel is travelling less distance than the front outside wheel. The transfer case that sends the power to the front and rear differentials is unable to compensate for this degree of difference and you feel the symptoms you describe above. This is also the reason that 4WD/AWD vehicles have to have the same size diameter tires on the front and rear.

In most circumstances, you can't notice this. But it is magnified in a very tight turn...and the IS has a decent turning radius. Hope this helps.

Posted
Since I got the car i've noticed that when I make a hard left or hard right turn it feels like the tires skip a beat, a little jerk, not a steady turn. This is only when the steering wheel is at a full left or full right. Casually driving I never notice this, it's usually when i'm making my way out of a tight spot like in a parking lot when I have to turn the car around. Any idea what this could be? Damaged tire(s)?

It is unlikely you're going fast enough in a tight spot for a parking space to be experiencing any degree of "understeer"...at least any that would be noticable.

I see you have the AWD, and what you are experiencing is most likely the wheel travel difference between the front wheel and the rear wheel. In any turn, the differential allocates the majority of power to the outside wheel. This is due to the fact that the outside wheel has a longer radius and a further distance to travel than the inside wheel. The differential simply see's this as the least resistance.

On your car, you have two differentials - front and rear. Since the rear wheels basically cut off the angle of the arc of the front wheel travel, the rear wheels are travelling a shorter distance than the front wheels. An exagerated (and somewhat incorrect) example of this is the hypotinuse of a triangle. More specifically, the rear outside wheel is travelling less distance than the front outside wheel. The transfer case that sends the power to the front and rear differentials is unable to compensate for this degree of difference and you feel the symptoms you describe above. This is also the reason that 4WD/AWD vehicles have to have the same size diameter tires on the front and rear.

In most circumstances, you can't notice this. But it is magnified in a very tight turn...and the IS has a decent turning radius. Hope this helps.

I feel this a lot too and I'm glad that someone brought it up because I always thought that the wheels were being turned at such a sharp angle that I was riding on my rims :o ...but I've never thought of it that way CrunchySkippy, thanks.

Posted

I've had this issue as well...and I have a RWD...I bought my car in Hawaii and it felt it somewhat...now that I'm stationed in VA...I feel it much stronger..and is mainly when I just start the car and come out of a parking spot...I thought maybe it's the cold...I have brought it to the dealer and they say they can't find anything....one day I got underneath the car and noticed the inner part of the rim seems some what scrapped all around it...it seems to be scrapping something but I can't see what it is...any assistance or suggestions would be greatly appreciated...and please common terms I know nothing about cars...

Posted

I feel the same thing on my ES and its FWD. I think its more what Bartkat was describing.

Posted
I feel the same thing on my ES and its FWD. I think its more what Bartkat was describing.

Try it in an AWD IS. For another exagerated example, try it in an older Jeep CJ or TJ in four wheel drive on dry pavement. Those Jeeps had short wheel bases and tight turning radius' (sp?). I think you'll experience exactly what LEXUS IS250 AWD was describing (jerky, skipping, and even hopping).

I'm not exactly sure what you're experiencing with the ES FWD. FWD's wouldn't suffer from either understeer or transfer case inequality. How wide are your tires? I suppose there are different arc's for the inside of the tire vs. the outside of the tire, which might be magnified by a wider tire. Dunno.

Posted

Here is a couple of links that may help explain what your saying CrunchySkippy. But no car has it down 100% thats why you either get drag or pushing in the outer wheel of the turn. MB's have the most pronouced effect of trying to correct this problem. If you notice when a MB has the wheel cranked all the way the tires lean like crazy.

http://en.wikipedia.org/wiki/Ackermann_steering_geometry

http://books.google.com/books?id=YRu95YYeB...result#PPA13,M1

Posted
Here is a couple of links that may help explain what your saying CrunchySkippy. But no car has it down 100% thats why you either get drag or pushing in the outer wheel of the turn. MB's have the most pronouced effect of trying to correct this problem. If you notice when a MB has the wheel cranked all the way the tires lean like crazy.

http://en.wikipedia.org/wiki/Ackermann_steering_geometry

http://books.google.com/books?id=YRu95YYeB...result#PPA13,M1

Thanks for the links man..I learned something new...still I can't see how my the inside of my rims seem scrapped all around...it's not a bad scrap but it's definetly touching something..it's all around the right on the edge by the tire...Hopefully I can take pictures next time..

Posted

JENunnez - That is an excellent visual explanation. It certainly helped me, and hopefully others as well. Thank you.

Pintoca - yes, try to post a pictures. Sounds like your upper control arm may be hitting the rim. You'd probably notice tire damage as well if thats the case. If its more inside the rim that you're describing, it could be something as simple as a piece of debris (gravel, etc) that lodged between the caliper and the rim. It doesn't sound normal, however I haven't exactly looked inside my own rims for comparison.

Posted
Here is a couple of links that may help explain what your saying CrunchySkippy. But no car has it down 100% thats why you either get drag or pushing in the outer wheel of the turn. MB's have the most pronouced effect of trying to correct this problem. If you notice when a MB has the wheel cranked all the way the tires lean like crazy.

http://en.wikipedia.org/wiki/Ackermann_steering_geometry

http://books.google.com/books?id=YRu95YYeB...result#PPA13,M1

Thanks for the links man..I learned something new...still I can't see how my the inside of my rims seem scrapped all around...it's not a bad scrap but it's definetly touching something..it's all around the right on the edge by the tire...Hopefully I can take pictures next time..

I have noticed the same exact thing on my '06 IS 250 AWD...the outside edge of the front rims are demolished.

Posted

The outside edges of my rims are pretty scratched up as well. Previous owner must've hit alot of curbs. From what the mechanic told me my insides are fine, no damage.

  • 2 weeks later...
Posted

I had my rotors/pads changed and the mechanic there couldn't figure out what it was hitting either...all 3 looked around for what spot the tire may be hitting but no luck...I took pics with my cell this time...I'm surprised this Navy computer allowed me to upload the pics

post-89142-1237379883_thumb.jpg

post-89142-1237379891_thumb.jpg

post-89142-1237379899_thumb.jpg

Posted
I had my rotors/pads changed and the mechanic there couldn't figure out what it was hitting either...all 3 looked around for what spot the tire may be hitting but no luck...I took pics with my cell this time...I'm surprised this Navy computer allowed me to upload the pics

That actually looks like rail damage from a car wash or the quick lube places. Nothing on the car would cause that.

Posted
That actually looks like rail damage from a car wash or the quick lube places. Nothing on the car would cause that.

I was thinking that almost looks like damage from when the wheel was removed from the car (maybe a brake pad change, tire rotation, etc) and was damaged from being laid/slid on the ground. You'll notice the wheel (rim) is actually very close, if not wider, than the tire itself.

Did you say all four are like this? Can you tell if the abrasion is directional or circular? -EDIT- It looks like it is circular. I'm changing my vote to something similar to Smooths suggestion of "rail damage".


Posted

it's on one tire only..the driver's front side...I just wish when I take the car in for service they could feel what I feel

Posted
it's on one tire only..the driver's front side...I just wish when I take the car in for service they could feel what I feel

Right, the one that you have to slip in between the rails to the stop marker that tells the car wash your in the correct postion so it can begin.

...I just wish when I take the car in for service they could feel what I feel

So what do you feel?

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