Bloodred

Ok, now I see what you're saying. Over wet or bumpy surfaces where one rear tire loses traction before the other, the toe causes the rear of the car to rotate on the direction the gripping wheel is pointed. That makes sense, since it would behave similar to a toed out rear when only one wheel has grip.

However, while I do see your point, I think this effect would be almost negligible with oem settings. Also, you wouldn't really see this effect on a smooth, dry surface (as you said). So it seems like a trade-off to me: do you prefer having the rear more planted over wet/bumpy/straights, or smooth/dry/cornering? Since I live in sunny southern California it's an easy decision for me

In the end, I think this really comes down to preference. Some people will be willing to deal with a little instability over rough surfaces in order to keep the car from oversteering in corners, some won't. After everything you've said, I think it probably is best for novice drivers to run a little less toe-in, since the car will be more predictable for everyday straight-line driving (reducing unexpected/"snap" oversteer). I'm going to stick to my settings though, since I've never had trouble keeping the car pointed straight over rough surfaces, and I find the toe-in keeps the rear gripping when I really need it in corners. Then again, I've autocrossed for 3 years but never tracked (yet), so things may be a little different in higher-speed, bumpier corners.

Thanks for the explanation. I never even thought about the effect losing grip on one side would have with toe-in

ZDan

In my experience, the car doesn't feel *any* more planted at the high end of the camber spec for the AP1. When I first tracked the car, I had the rear toe set toward the max end of the range to minimize oversteer as I was on very little tire tread width stagger (225/245 VictoRacers). I had camber maximized all around, zero front toe, and ~0.55 total rear toe (my info had the spec range as being 0.32* to 0.64* total).
Anyway, first hot lap and I was going to "take it easy" a bit, and feathered the throttle just a bit at the left-hander going up the esses, more of a breathe than a lift, and the back end definitely got a little bit antsy. Experienced an initial oversteer lurch, followed by neutrality (a function of the goofy rear toe-in with bump "feature"). Not a problem, but I had expected the high rear toe to subdue it a bit.

After two days at the Glen and one day at Mosport dual-driving the car (equivalent of 4 driver-days), and the new rears were GONE. The car became a near-undriveable beast the second half of day two at Mosport, the rears were just DONE. By the time I got home the middle third of each rear was corded!

This kind of rear tire wear wasn't going to work for me, so I had to try less rear toe in the interests of tire life. I asked for 0.32degrees total, or 0.16degrees per side. Instead they gave me 0.15* total! It was not without some trepidation that I took it to the next event at Mont Tremblant on a new set of donated Kumhos (205F/225R this time). The S had seemed somewhat twitchy to me at the Glen, and was nearly undriveable by the middle of the second day at Mosport, so I was worried about getting too much oversteer. But lo and behold, the car behaved pretty similarly. If anything, it seemed to behave more linearly and the rear toe monkey-motion with bump wasn't as apparent.

And the rear track tires lasted a LOT longer, at least twice as long vs. with the higher rear toe setting.

That experience of back-to-back events running 0.55 rear toe at one and 0.15 at the next, plus accidentally running it last year with over 1degree rear toe and having diabolical handling even in a straight line in the wet on the road and at the track, and I've pretty much decided that LESS rear toe is BETTER all around. To a point, I wouldn't recommend less than maybe 0.2* total to a novice.

In my experience, running minimal rear toe might improve pointability a bit, but it doesn't give more oversteer in turns. Actually, if you think about it, having more rear toe-in could REDUCE your total lateral grip at the rear, as the inside rear is operating at a lower slip angle, not contributing as much lateral grip as it would with lower static rear toe.

[edited response] [edited out my previous response, where I totally missed your point here!]
Exactly, I think that rear toe at the lower end of the AP1 spec (~0.3 degrees total as opposed to ~0.6 degrees) does make the car more predictable and linear in its responses.

I don't think you're getting any more rear grip with more rear toe, and you might be getting a tiny smidge less (inside rear not contributing as much). The difference is behavior at corner entry, and the attitude/angle at which the car will be while cornering.
How much rear toe are you running now? You might try something like 0.2 degrees total and see what you think. I would think that it would be even better for autoX than it is for road course work. I *promise* it won't hurt a bit!

Honestly, my experience is that minimal rear toe is better for turn-in, better for linearity/predictability of handling, and better for fuel economy, too!

Counter to the conventional wisdom in some ways, but that's been my experience with it over the past few years.

mesko401

I also noticed a difference in handling and predictability after lowering total rear toe on my AP1. I originally had the car aligned to the U.K spec, and after having the car re-aligned, the shop insisted on going towards the minimum side of total rear toe, aprox .2 total. They said if I was disappointed that they would change it free of charge.

The change was noticeable, the car was more planted, and the rear end was less squirmish. Also the car pointed much better, with reduced under-steer. I was very happy with the results.

So my two cents would also be to try a lower total rear toe, with the more aggressive camber of the U.K alignment.

On a more important note, and as most have mentioned, less then par tires, no traction control, and novice driver that wants to experience handling abilities of the S in the wet or dry = just a matter of time before another S hits the junk yard. Trust me, I've almost been there, and had many friends have ended up that way.

After owning the car for several years, you learn to understand it is definitely a very temperamental car, where you have to learn its limits, and run high quality extreme performance summer tires, if you care about your car and your life, and you plan on driving more aggressively.

After owning a set of Goodyear F1 GSD3s, two sets of Hankook RS2s, the Bridgestone RE-01Rs, and the Dunlop Z1 Star Specs, I can hands down say the Z1 star specs are my favorite tire. Excellent grip, sidewall stiffness, and wet traction, with a very affordable price. Plus, I have been very impressed by the wear of the tire as well.

On a side note, the RE-01Rs, were the most expensive, and by far the fastest wearing tires I have ever owned. Not sure how the RE-11s compare..

I have had too many friends with brands such as Sumitomo, Fuzion, and the likes, or who were running what they believed were "high performance summer tires" end up hitting guard rails and dividers in the dry in spin-outs, because they were in a similar situation as you, and didn't take my words of wisdom.

So good luck, and at least get out to a local auto-cross, there are plenty of people that are more then happy to teach you how to improve your driving skills, and you will learn a lot about your car in a safe and fun environment.

P.S. throw those tires out and invest $500-600 for one of the best investments you can make on this car, not only will it save you a lot of heart ache, you will also enjoy the much improved handling of the car.