Am I supposed to ask for a 2-wh or 4-wh alignment?

You can ask for a four wheel alignment, but you may not get it, due to the shims. Still, it would help to have the specs for the rear, even if it isn't changed. Note that 'thrust alignment' may involve a large hammer.

 

Thrust angle (and toe--the real culprit in most cases) is what has been out in the other vehicles I've owned at delivery. I've always asked for 4 wheel alignment on my other vehicles. That free first alignment has always helped. Which reminds me...I need to have the Prius done within the next few months. It is the first new car I've had that wasn't obviously out of alignment upon delivery so I've been saving this one for tire rotation time.

You can see if thrust angle is out by following your vehicle (with someone else driving). That's how I've always checked mine out. I let the wife drive while I follow to see if it is tracking straight or crabbing sideways like your typical domestic truck (which always seem to have a running lamp or two out as well.) The dealers would argue that I couldn't tell by looking that way...but I was always right about it being out and the direction it was out.

 

I got one of my alignment checks at Les Schawb. Make sure to tell them that you want the readings for toe-in to be in decimal degrees (best) or at least in decimal inches (what I got). Otherwise they will probably give you toe-in in fractional inches and you won't be able to figure out the shim thickness if you need them to adjust the rear.

If they do a thrust alignment and you shim the rears, then you will have to redo the alignment again (shimming the rear will change thrust angle). I think its best to get them to do a 4 wheel alignment check. They won't be able to adjust the rear, but you will get the readings for the rear wheels.

 

Front looks good to me ( a little negative camber helps stability)(.5 max to me). The back looks like mine. I can visually see negative camber and toe. Most vehicles use a half or full plate contact ring. I have made some in the shop when I was a cheap fat bastard. :lol:

 

Basically, all that was done to your car was to correct front toe-in to zero. If you find an alignment place that is willing to install shims for the rear, you might be able to have the rear toe-in set closer to zero, which may give you slightly improved mpg.

 

So camber is not adjustable in the Prius on the front?
I am sure the rear is a deliberate design feature by Toyota for stabilty. Maybe. Every odd Sunday on leap year. Still that is a little too much negative toe for me. .03-.07 would be ok in my opinion.

 

Front camber is adjustable, but it does not appear that adjustment was made to the OP's vehicle since the before/after results are almost identical. The way to adjust it is to loosen the two bolts that are at the bottom of the strut, and push the strut in or pull it out as needed; then tighten the bolts.

 

Thanks man! I assume that Toyota does not want -.7 in the front?
Sounds a little much to me.

 

Ok you are good to go on the camber man. My Corolla or Sonata (can't remember) was the same way. That does make for a stable car.

 

I am a newbie so take this with a grain of salt. But I always used full contact alignment contact rings on other cars. So I assume you can not do that on a Prius. I have not seen the wheels off this beast so forgive my stupidity.

 

Actually, your rear toe is not that bad. I'm not sure that I would attempt to change it if you are at .15 inch on the left rear and .18 inch on the right rear. Spec is .12 ± .10 inch total or .06 ± .05 each side. So you are just a tad too much. But at least its even from side to side.

I figured out how to convert from decimal inches to degrees here:

http://priuschat.com/forums/care-ma...2007-model-alignment-issues-5.html#post455187

It may not be exact, but close enough for Galaxee's DH to figure out shim thickness.


Your front camber isn't that bad, it is within spec. I adjusted my front camber in the driveway after the dealer screwed it up.

 

Time for Autocross Alignment 101: based on my years auto-crossing, negative camber (tires leaning in at the top as viewed from the front) provides better handling but will wear the inside of the tires more in steady-state driving. Negative camber adds oversteer (loose to NASCAR types). Positive camber (tires leaning out at the top as seen from the front) increases understeer (push to NASCAR types) and, therefore, perceived stability (not the "perceived" - oversteer is uncomfortable to some people, but that doesn't mean it is less stable. In fact, it can inmprove handling if you know how to drive such a set-up).

Negative caster (hard to visualize and impossible to see, but the center line through the vertical pivot axis intersects the ground in front of the tire contact patch) provides self-centering. This is because the contact patch wants to return into trail behind the pivot-axis point.

Conversely, positive caster is when the contact patch is forward of the vertical pivot point. This makes the car turn off-center easier (and not want to stay self-centered) because the contact patch wants to "flop" from side to side around the pivot point. This is advantageous for autocrossers who want the car to respond left-right-left-right as fast as possible. It feels like it is unstable at speed.

Toe-out also leads to a "hunting" feeling at speed, as the car will try to "dart" in the direction of whichever front tire is getting the best grip at the time. Toe-in helps counter this, but adds "scrub" and, therefore, increases tire wear and reduces gas mileage. Some cars work well with some toe-in, however.

My Neon ACR autocross car ran zero toe-in front and back, as much negative camber as we could get (about 3 degrees in the front and as close to that as we could get in the back) and a degree of positive caster in front. These are relatively radical settings for the street, made the car feel GREAT in cornering, adequate straight-line, and was hard on DOT-legal racing tires on the street. Some racers actually ran some toe out on the back to get the rear to come around quicker, but others of us didn't like the feel of the car with that setting. I thought it felt absolutely dangerous at 75 on the interstate set up that way.

 

So that much negative toe in the rear is good to go! Has anyone noticed the tires scrubbing out in the back?

 

Keep those cards and letters coming man. Thanks!:biggrin1::hand:

 

Actually on second thought, Justin your LH rear is .15in = .29 deg and RH rear is .18in = .35 deg. You would rather be at .15 deg per wheel.

Maybe you should PM Galaxee and ask DH's opinion.