Local shop just installed my new tires and did a "specialty alignment" - total cost $206 ($110 for the alignment).

Manager claimed he used to "make a living working on Porsche" and his assistant claimed to be a former 944 owner.

Still, I provided him the shop manual and Wally Plumley's posting stressing the importance of settling the car correctly and keeping weight on the wheels...

They used a Hunter machine but I'm wondering about these numbers they showed post alignment.

Camber: -1.0 (Left front), -0.7 (Right front)
Caster: 5.3 (left front), 6.2 (Right front) *** isn't that out of spec still???
Toe: +0.13 (left front), +0.13 (right front)

Camber: -0.7 left rear, -0.7 right rear
Toe: +0.18 left rear, +0.12 right rear

The front's toe was out and off the chart prior to ... but the caster numbers haven't changed at all (pre to post alignment).

Do I need to be concerned by any of these numbers? He gave me a 6-month warranty on the alignment.

Ride's nice - I like the new Sumi tires.

Mike

 

Mike,

The hunter unit is considered the best.
I had my 86S aligned and corner balanced last week after new springs were installed at a Porsche suspension specialist shop.
My measurements are as follows:

Front left camber -0.39
Front left caster 4.47
Front right camber -0.35
Front right caster 4.56
cross camber -0.04 crosss caster 0.09

Front left toe 0.16
Front right toe 0.16
Total toe 0.32
Set back -0.11

Rear left camber -0.71
Rear right camber -0.62
Rear left toe 0.17
Rear right toe 0.18
Total toe 0.35
Thrust angle -0.01

Good Luck
Rich

 

Mike:
Front:
Camber seems very aggressive for the front - plus they are not even close to being even. You may want these re-checked. I've posted the specs for the 928 below.

The caster figures are off, but too much caster shouldn't hurt much (this is setting that induces the steering wheel to recenter itself after a turn.) The caster figures should at least be equal from side-to-side.

Toe seems fine - this is the most critical measure for the 928's alignment. I have to ask... did they lift the car?

Rear:
Camber is out of spec but even. Depending on your driving style, this setting may suit you. I'm running -1.2 camber IIRC. At least they are even from side to side unlike the front.

Toe is out of spec for left rear. Right rear is in spec, but could be better. With the the two toes not being equal, you have a condition called thrust angle. Basically the leading edge of the left tire is pointing in more than the right tire. This is going to cause the entire back end to push to the right. I had this but on a much worse scale and when I hit bumps, I could feel the rear end wanting to shift directions. Your's isn't that bad, but they should have been able to make both sides even so you have zero thrust angle.

To sum up, if they did not lift the car, you got an okay alignment (only becasue the toe is in spec). Front Camber is VERY agressive and way off from side to side and should not be this way unless you asked for it. I'd probably go back and tell them to re-do the whole thing and bring it into spec, or at least show you why they can't bring it into spec (those eccentrics will only move so far).

 

The caster is hard to get below 5, but the difference is out of spec and may cause the car to pull. Did they comment that 6.2 was as low as they could get the right side? If that was so, I would have set the other side up to 6.

Toe difference in the rear can cause dog-tracking.

Why is the camber high and different right to left in front?

How does the car track down the road?

 

Thanks for the feedback.

I didn't ask for an agressive set up and I thought I went a bit overboard by ensuring they understood the car shouldn't be lifted prior to the alignment taking place. I told him I thought my front tires were evidence of this probably having occurred with the last alignment...the inside treads wore to the cord in less than 5K miles. I even circled Wally's comments on a printout I gave them discussing 928 alignments, and gave them an excerpt out of the shop manual.

I'll ask if he can even up the right and left side for me, and ask about the caster adjustment. The manual talks about the need to turn back the eccentric completely before adjusting the caster to the correct value.

The car seems to pull just a bit to the right. Post alignment thrust angle shows 0.03 and total toe front is at 0.26 and rear 0.30.

I was hoping the new tires would also stop what I thought was tire noise in back...believe now I've got a bearing going bad.

Thanks for the help! Mike