NB Rear Toe Setting for Azenis Street Tires?

[azcarguy]

I autocross a '99 Sport that is C Stock legal. I run in a highly competitive local Street Tire Class and use the Azenis 615 (205x50x15) running 30# front and 28# rear pressure. I have the Goodwin C Stock kit ........RB front bar, bracing blocks, muffler, K & N, Konis (1/4 turn from full hard front, 1 turn from full hard rear).

The alignment (which I previously used on a '92 LE E Stock Miata with similar equipment) is:

Front
Toe: 1/8" OUT
Camber: -.9' (degrees) both sides
Camber: 5.5

Rear
Toe 1/16" IN
Camber: -1.7' both sides

My problem is that with this setup I have twitchy, uncatchable oversteer (asphalt course mostly second gear). With these exact same settings (but on Victoracers with viscous limited slip)) my '92 was very tossable and controllable.

All camber bolts and other attachment connectors are tight, front sway bar mount is not broken.

Before this alignment I had a "home-done" alignment that was basically the same in front but I had more than 1/8" toe in for the rear, and it was stable in corners. I had a "professional" alignment done to the above (previously successful) specs and now have a slower car!

Is it that the street tires can't be tossed like the "R" tires? I could easily "toss and catch" the '92 at will and plant it anywhere I wanted. Not so with this '99 Sport (factory limited slip).

Have I found my culprit? I have local Miata autocrossers telling me that some Miata drivers (CSP) use ZERO rear toe, and this can't be my issue.

Any and all advice and opinions appreciated.

[Brian]

I suspect that the pro alignment got screwed up...because it sure sounds like you have postive rear toe. Were you sitting in the Miata at the time the alignment was done? The problem with the modern "computer" alignment is that if they drop one of those sensors on the ground it is USELESS until the shop calls the maker to come out and calibrate it again. Thus, I suggest going to another shop to have the alignment checked. If it turns out to be okay then you can dial in a little more rear negative rear toe.

[azcarguy]

Ding, ding, ding....we have a winner!

I went out to the garage and preliminary measurements show either zero rear toe or perhaps even a little toe-OUT in the rear. Definitely not toe-in.

Thanks. Who would'a thought......?

Next up.....I believe that I read the Andy Hollis STS2 car runs the 615 Azenis (I know it's different suspension, etc.) but he also shows from his articles about 34# pressure. I'm at 30# front and 28# rear with good edge rollover readings.

Am I too low too perhaps?

[Brian]

I think you could try a pound or two higher on the PSI but there also a lot of personal preference in the tire pressure equation.