Yuri101

So i noticed when i turn the wheel all the way when im reversing or going forward one way the car begins to like slip/rock/make wierd movement. What can this be ? 2009 lexus is250 awd
apx. 45k miles

LEXtegra

That's just the AWD system. Don't worry its not a problem.

Yuri101

Alright thanks for the reply, but can someone explain to me how that happens?

jgbackes

iTrader: (2)

If you were to drive your car in a way that would leave marks on the ground you would notice that there are two circles of different size on the ground inner and outer circles.

If you do the math you'll find that the difference in the circumference of the circles is a factor PI. Take the track of a car and multiply it times 2PI and that's how much farther the outer wheel has to travel around a circle. The sharper the turn the less room the outer wheels have to make up the difference.

So... The tighter the turn the more "hopping" the tires have to do to make up the distance. All the four wheel drive cars/trucks I've driven have this "problem" The outer wheels have to travel farther than the inner wheels.

jeff

funglenn

iTrader: (10)

true, my 4x4 4Runner did this, as did an AWD volvo i had, and so does my IS . Very common and no reason to worry. If you did not have an AWD, then i would have been very concerned. That is also paritally why they always highly recommend we have matching wheels,all worn evenly and same tread--to help cut down on the differences they must travel.

mikez

Isn't that what the differential is for? Allowing the inner wheel to spin less than the other wheel to make up the difference so there is no hopping?

jgbackes

iTrader: (2)

Most AWD systems don't have a standard diff for the front wheels.

Good writeup: wikipedia