Rear Wheel Angle

<div class='quotetop'>QUOTE(newkbomb @ Nov 1 2006, 01:25 PM) [snapback]342122[/snapback]</div>

Here is a link that explains some basics of alignment:
http://www.ozebiz.com.au/racetech/theory/align.html

 

Cornering stability

 

Front : Left & Right

Specified Range
Camber ................. -1.3 ..... 0.2
Caster ................... 2.4 ..... 3.9
Toe ....................... -0.1 ..... 0.1
SAI ....................... 11.8 ..... 13.3
Included Angle ....... 10.5 ..... 13.5

Front

Cross Camber ........ -0.8 ..... 0.8
Cross Caster .......... -0.8 ..... 0.8
Cross SAI .............. -0.8 ..... 0.8
Total Toe ................ -0.2 ..... 0.2


Rear : Left & Right

Specified Range
Camber ................. -2.0 ..... -1.0
Toe ....................... 0.03 ..... 0.28

Rear

Cross Camber ....... -0.5 ..... 0.5
Total Toe .............. 0.05 ..... 0.55

Go to Firestone and get the $99 lifetime alignment on sale. B)


Just curious if anyone knows why the rear wheels are slightly angled in instead of straight up and down?


Stability

 

Mine are angled. They lean into the car. The angle got slightly bigger after the TRD suspension, but it does a lot for handling. Just rotate your tires frequently and you should be able to minimize uneven tire wear.

 

I'm assuming you are talking about how the top of the wheels leans into the car when looking from the rear. That's called negative camber (Positive would be leaning out instead of in.) In most cars a small amount of negative camber is added to make up for the amount of body roll in turns, so that when cornering the outside tires (which do most of the work) are closer to vertical. On Macpherson/Chapman strut suspensions like on the Prius (and most other cars these days) the suspension can't vary camber actively as it compresses so a little extra negative camber is dialed in by the factory.

Camber has a pretty big effect on the handling balance of the car. Without a little negative camber in the rear, the car would feel much looser in turns.

BTW, it's toe that makes the biggest difference to the stability of the car, especially at highway speeds. Add a little rear toe out and hang on for the ride! In general, toe-in stabilizes the car, toe-out makes it want to turn.
Of course, moving any of these settings much past 0 will increase tire wear, and in the case of toe will also reduce fuel economy.

 

<div class='quotetop'>QUOTE(narf @ Nov 2 2006, 10:26 AM) [snapback]342521[/snapback]</div>

Thank you; concise ideas like this really help me visualize what's going on. I remember seeing an old Bugatti with tremendous amounts of toe-out, perhaps that's why.