Do I really need a shim on the Right Rear Wheel

[Ed_Strong]

This thread sort of continues the old Is it an Axle (CV Joint), a Wheel Bearing or Tranny issue? thread...! I just don't want to derrail the discussion going on there so I decided to do a new one.

Well, to follow up, the van is eating the front tires at the outside edge, I had new tires put on back in 11/2008 and they're new inside and worn out outside now. After three attempts to get it alligned at one shop with no success, (last one was done 11/2008 right after the new tires went on), I went to a different shop today and they found out the front end toe in-out was way out of specs. I think the previous shop saw me coming and took me for a ride!

Toe Readout Before Work
LF. 0.60º . . . 1.30º . . . RF. 0.70º

LR. 0.20º . . . 0.05º . . . RR. -0.15º

Toe Readout After Work
LF. -0.10º . . . -0.20º . . . RF. -0.10º

LR. 0.20º . . . 0.05º . . . RR. -0.15º
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Camber Readout Before Work
LF. -0.7º . . . . . . RF. -0.8º

LR. -0.2º . . . . . . RR. -0.4º

Camber Readout After Work
LF. -0.8º . . . . . . RF. -0.8º

LR. 0.3º . . . . . . RR. -0.3º
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This new shop performed a Thrust Wheel Allignment and determined the the right rear wheel needs to be shimmed to bring it up to specs ([green]0.20º[/green]) with the left rear wheel.

The didn't have the "shim kit" in stock so when they get it, they'll notify me so I can go back and get it done.

My question is... has anyone ever had this done before or heard of this? I asked them if it would hurt driving like this till the kit comes and they said that the right rear wheel was off by so little that it wouldn't hurt anything.
If you were to look at the diagram they gave me, you'll see that the tire is right in the green/red zone split, so it's off by a hair.

So I'm thinking of just telling them not to do it and save the $150 it would cost to put it on. What do you guys think?

[Ed_Strong]

No one?!? Weird!

[parkerb]

yes i've heard this during an alignment, however since that time, everytime i'm in for one they just do a front alignment, don't even bother with the rear unless accident or such.

[12Ounce]

Some suspensions, by design, use rather short members (no jokes, please!); and shims are used to get the inner pivot points "just right" ... my old Nissan truck is of this style. The geometry of the Windstar is huge in comparison. From the top of the strut, to the bottom ball joints, back to the pivots of the lower control arm ... a number of inches in each direction. I don't think a shim will make much difference. The welded body is jig/machine welded and checked often during periodic checking routines. The subframe can float a bit, but I've never seen an issue after dropping and re-mounting several times. Now if the car has been involved in a big fender bender then all bets are off...also if there is huge wear on wheel bearings or rubber bushings ... but otherwise, toe-in adjustments should be all this car ever needs for good tire wear. I had one set of Michelins go over 100k miles ... now, admittedly, I was pushing it ... but no cords were showing.