New alignment - steering went slopy 1/2 way home

[CL65 Captain]

Put on new Goodyear F1GS3s so I took the car to get aligned today. New shop in town was highly recommended (they were working on P GT2 while I was there). I had inner front tire wear, but a bit excessive - 12,000 mile. Car is 90% street - with 2-3 HPDE. So they went with a less agressive alignment for the front. Rear was wearing flat across so they just cleaned it up (matched them).

On the way home, about 1/2 way I noticed the steering all of a suddent changed. It got real light and very sloppy... you can move it back and forth like you are driving a Cadilac. Shop was going to close before I could get back there so I am going in again tomorrow.

Pic attached of the alignment specs... do you think they went too far on zeroing out the front specs? It seems like something came loose on the drive home... I am going to make them do the alignment again as well as tighten up what came loose so should I suggest any changes to the current settings?

Jim

 

[titaniumdave]

The toe was wearing your front tires, not the camber. That toe number is gigantic! That little camber on the front will make you car push like crazy on turn in, if you can get the car to rotate under throttle, the rear end will span around pretty quickly. Put the camber at the high end of stock and the toe at the low end and you should be good to go, IMHO.

Having the 'feel' change 1/2 way home indicates something changed, make sure they check all of the linkages when you get it back on the rack.

 

[nsxtasy]

The toe was wearing your front tires, not the camber. That toe number is gigantic! That little camber on the front will make you car push like crazy on turn in, if you can get the car to rotate under throttle, the rear end will span around pretty quickly. Put the camber at the high end of stock and the toe at the low end and you should be good to go, IMHO.

Having the 'feel' change 1/2 way home indicates something changed, make sure they check all of the linkages when you get it back on the rack.

 

[CL65 Captain]

After searching and reading, and searchng and reading....

How about -1.5 deg front camber and 0.10 toe for the front? Is this too agressive? Looking at the FAQ, it says factory setting is 0.33? Is this mm? If so what is that in degrees? What is a good compromise? Confused. How much of a difference will it make for a novice like myself? And does that mean -1.5 deg L and R? Sorry for the dumb questions, I am trying to learn what to tell them tomorrow when I go in.

Car has NSX-R chasis braces, NSX-R front sway and Goodyear F1GS3s. It is not a "daily driver", but I do use it for nice day drives and I plan on trying to do more HPDE next year (going to Autobahn CC Sept 30- Oct 1 for my second one :biggrin: ). But it isn't going to be a track car.

Jim

 

[CL65 Captain]

Update ...

Took it back to the shop and they checked everything and said nothing was loose and the alignment was pretty close to when it left yesterday. So they added more camber and a little more toe to the front and reduced the toe in the rear. The car still drives exactly the same.... very sloppy and very unstable. I feel like when I steer to the right that I then have to correct back to the left because it feels mushy... like driving a Cadilac.

I know that I had tons of front toe before, but the car is more "in spec" now and feels really, really unstable. Any sugestions???

Revised alignment....

 

[titaniumdave]

The new numbers indicate the rear end has toe out, it should have toe in!

That can account for some of the feel. The caster numbers were closer side to side on the first alignment, seems like they should be able to do better. For my taste, I like to maintain about 0.7-0.8 degree more camber in the rear than the front, it is a good balance for me. Having less differential may make the car a bit tail happy when pushed.

Here is what I run all the time for spec, works well on the track with street or R-compound tires and is not to aggressive for regular weekend drives:

Front:
camber; -2 deg
Caster; 8 deg
toe; -0.1 deg

Rear:
camber; -2.8 deg
toe; +0.1 deg

These numbers will make the car tend to follow the 'truck ruts' on the freeway, so I wonder if the loose feeling is only on one section of road. The next thing to look at is to see if the tires are inflated correctly, 33 front, 40 rear. (Seems like when ever I get tire work done, the tires will come back to me at 38 all around, makes the car handle like crap...) Next step would be to swap wheels and tires and see if things change, I am assuming the shop has checked for loose suspension bushings and tie rods.

Have made any changes to the suspension??? Have you had the Goodyears before? I found these to be the worst tire for having the 'truck ruts' move the car around when they were new, got much better as the tires wore down. I assumed it was because the tread blocks are narrow, makes for a great wet weather tire but seems very sensitive to road surface irregulaities.

 

[CL65 Captain]

Are those total #s or for each side? ie -1.0 L & R for camber
Is the toe the total toe?

What effect would adding more toe have? Say going for -0.2 total toe? Woudl this make the car feel less "spongy". My previous setting had a whopping 0.54 but felt rock solid (at the expense of my front tires of course).

 

[nsxtasy]

Any sugestions???

Consider taking it to a different shop, maybe?

 

[nis350]

The spec. on the rear toe is definitely wrong.

Not sure how the machine has the wrong spec...