Question about WRX SAI alignment angle

I had my MY03 WRX wagon aligned and the SAI secondary angle was measured at 10.25/8.83 (left/right). The spec for SAI is 13.83 - 15.33. The alignment guy said this is not adjustable but could be indicative of mechanical damage. His advice was it was no problem and to ignore it. I called one local Subaru dealer and the service manager didn't know what SAI was. I called another dealer and the service guy (who at least knew what I was talking about) also said don't worry about it.

I should add that all other alignment angles are in spec after the alignment.

Does anyone who knows more about alignment and WRXs than I do have a thought about whether SAI out of spec is something to be concerned about?

Thanks in advance, Bob

Reply to
Bob Lund
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Steering Axis Inclination (SAI): The angle formed by a line that runs through the upper and lower steering pivots with respect to vertical. On a SLA suspension, the line runs through the upper and lower ball joints. On a MacPherson strut suspension, the line runs through the lower ball joint and upper strut mount or bearing plate. Viewed from the front, SAI is also the inward tilt of the steering axis. Like caster, it provides directional stability. But it also reduces steering effort by reducing the scrub radius. SAI is a built-in nonadjustable angle and is used with camber and the included angle to diagnose bent spindles, struts and mislocated crossmembers.

Like he said, not much you can do, unless it is a damaged strut, assuming the MY03 has struts. Unless the edges of the tires are showing excessive wear, I would not worry.

Blair

Reply to
Blair Baucom

Thanks for the reply.

The reason I got the car aligned was from excessive wear on the inner shoulders of the tires. Both the toe-in and SAI were out of spec. The alignment adjusted the toe-in.

I believe the MY03 WRX has struts so I am left with the uncertainty of whether the out of spec toe-in was responsible for the unusual tire wear or if there is strut damage (as evidenced by the out of spec SAI).

Either replacing the struts or going through another set of tires is going to be an expensive way to find out. I was hoping to find some information that would help me figure out if a: strut damage is likely given the SAI measurement and b: if there is damage is it enough that it will affect tire are. I don't know if the struts can be looked at to determine their health; I'm guessing not.

Bob

Reply to
Bob Lund

Not sure if a strut can be rotated 180 degrees and then rechecked. If it is bent, this should shift the SAI. The other thing would be to swap left for right. The other option is a body shop which could check the car for alignment issues using a laser that is normally done for unibody repairs after an accident.

I know this decision is tricky as the checks may exceed tire costs due to excessive wear.

Blair

Reply to
Blair Baucom

The toe-in out of spec could cause the kind of wear damage you describe. That's what toe-in out of spec does. So now just wait and watch and you'll have your answer. If you start to notice uneven wear, do something about it before it gets too bad and it won't be a problem.

Reply to
Bob Noble

These guys are dead on correct with the information. I have had training in SAI and I still have difficulties with it. Bottom line, if Camber, Caster and Toe are within spec; don't sweat SAI. As far ar struts go, mostly sub's bend at the bottom and cause a camber problem, sometimes the control arms bend too, all will throw the camber/caster out.

Dive it; if it dosn't pull/drift or wear tires you don't have a problem.

Steve ASE Master tech.

Reply to
StephenW

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