Rear Wheel Angle

newkbomb · 11-01-2006, 03:25 PM

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

tumbleweed · 11-01-2006, 05:03 PM

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

Quote:

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

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

silentak1 · 11-01-2006, 05:35 PM

Cornering stability

grasshopper · 11-01-2006, 07:12 PM

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.

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

Stability

DocVijay · 11-02-2006, 10:11 AM

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.

narf · 11-02-2006, 10:26 AM

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.

Pinto Girl · 11-02-2006, 08:56 PM

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

Quote:

In general, toe-in stabilizes the car, toe-out makes it want to turn.
[/b]

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.

11-01-2006, 07:12 PM	#4
grasshopper Senior Member Join Date: Jan 2006 Location: Myrtle Beach SC Posts: 413 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	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. Just curious if anyone knows why the rear wheels are slightly angled in instead of straight up and down? Stability __________________ John Wood .... Be one with the Cosmos, Grasshopper 2006 Pkg. #3 Silver Pine Mica, Coastal Receiver hitch, Coastal EV switch, Formula one Panicle Ceramic tint 35%, Custom Pin Striping, Door Guards, BT Stiffing Plate, all weather matts, Venture Shield 12 mil Clear Bra. Heat screen, Side molding, Custom arm rests, Raised front of driver seat, 4 inch strip of tint on windshield, Canvasback Cargo Liner, Fumoto Oil Valve w/nipple, Mudflaps, Champion seat covers, Dog hair, Candy bar wrappers.

11-02-2006, 10:26 AM	#6
narf Senior Member Join Date: Mar 2005 Location: Colorado Posts: 525 My Car: 2008 Prius Package: #6 Touring Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	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. __________________

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11-01-2006, 03:25 PM	#1
newkbomb Join Date: Aug 2006 Posts: 22 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Just curious if anyone knows why the rear wheels are slightly angled in instead of straight up and down?

11-01-2006, 05:35 PM	#3
silentak1 Senior Member Join Date: Jul 2005 Location: Los Angeles, CA Posts: 546 My Car: Other Non-Hybrid Package: N/A Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Cornering stability

11-02-2006, 10:11 AM	#5
DocVijay Senior Member Join Date: Sep 2005 Location: Tampa, FL Posts: 1,455 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 1	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.