JLUDE

My apologies, I misunderstood. I am aware of the differences between Toe, camber and caster angle.

While I can see how some rear toe-in may help in corner exits, any toe setting that is not "0" is going to drastically increase tire wear. It's a trade off I suppose.

aCab

actually, a 0 static toe setting can become toe out as the car runs down the road and force it put against the tires. I prefer to start with a little bit of toe in so that as the car goes down the road, it is closer to 0.

Woodson

I expected this as well, but I did not notice any difference in wear.

ZDan

In my experience in the rain and in the dry, on worn tires or new, on track and on the road, excessive rear toe is more twitchy and evil-handling than minimal rear toe. Somehow (adjusters not fully tightened, probably) I wound up with ~1degree total rear toe-in, and it was an absolute BEAST in the rain at Mont Tremblant. ALL over the place. Also a tiny bit of a handful in the dry at Watkins Glen.

I also ran through a new set of Dunlop Sport Maxx TT tires in less than 3k miles (including 2 days at the Glen)!

I once had the rear toe accidentally set to 0.15 degrees total (instead of the 0.15 degrees per side I'd requested), and the handling was a lot more linear and predictable than with out-of-spec rear toe on the high side.

I like to keep rear toe at the lower end of spec, or less, even.
I usually run 0.20 - 0.30 degrees total (0.10 - 0.15 degrees per side).

Unless there's a compelling reason to, I hate the idea of scrubbing tires excessively with a lot of toe-in anyway, and in the case of the S2000, I don't think there's a compelling reason.

CBRdream21

And that's why my response was to the guy (Bumblebee) that posted right before me. You know, the one that said his tires are shot and asked for suggestions.

Bloodred

First of all, too much of a good thing is often a bad thing. If your car is way out of alignment spec, of course it's going to handle like crap. I imagine very large amounts of toe-in will give the rear a higher rolling resistance than the front, causing it to slide easily.

Also, alignment settings can be a matter of personal preference. Less rear toe-in will make the car more agile, but less stable accelerating out of corners. For a novice driver, sticking to the Honda recommended settings (or slightly more aggressive UK settings) is a good idea.

Finally, a little toe-in in the rear barely seems to affect tire wear in my experience. I run a modified UK alignment (with a little more camber all around), and I usually go through 2 sets of rear tires every set of fronts. From what I've read, that's pretty normal even for those running less toe.

Front toe, however, will really eat up tires, especially when driven hard.

rosodigital

First of all the BMW has all kinds of fancy electronics and more than likely $$$ tires... To think you could pull the same stunt with crumby tires and a very basic tcs you're crazy. I have some of those tires on my car... I just got it a couple months ago... They are terrible... The other thing is to use your brain. I hate it that so many s2's end up totaled because some dumb dumb thought he was on a Hot Version taping or something. If you want to hot dog find an open parking lot and find your cars limit, then stay far far away from it on the street. The s2 is quick but if you can only drive in a straight line, you'll never know it's full potential.

ZDan

As is too much of a BAD thing!

I think the real issue is that, the more rear toe you have, the more the back of the car will move around any time one of the rears gets loaded more than the other, or any time one of the rears has more grip than the other.
In grip-challenged wet conditions on track and on the road, in my experience, way less the minimum spec rear toe (0.15deg total) was MUCH more stable/predictable than way more than max spec rear toe (just over 1deg total).

Agreed, and my preference has always been for minimal rear toe to minimize rear scrub for reduced drag and tire wear and understeer. But my unintentional test of two extremes (.15deg total vs. 1deg total) gave me more to think about. There's likely some "optimal" rear toe for confidence-inspiring handling, but I think that level is a lot lower than one might think...

Accelerating out of corners is generally an understeer-inducing situation. And the AP1 is already giving you a ton more outside rear toe-in under acceleration anyway due to silly/gimmicky/bad-idea designed-in rear toe-in w/ bump travel. Which is the primary reason for uninitiated drivers spinning the AP1 in particular: Back end gets a *little* loose on the gas out of a low-speed turn, driver lifts off the gas, which induces a dose of oversteer from unloading the rears PLUS *another* healthy dose of oversteer from the outside rear toeing relatively outward (going from more toe-in to significantly less as suspension extends). Instant spin.

But anyway, aside from that, consider that with more static rear toe-in, the outside rear is higher up on the grip vs. slip-angle curve. Which means that it is closer to the point where increased slip-angle ceases to give more lateral grip. Which means that you can actually get GREATER oversteer due to having MORE rear toe-in as you reach the limits of adhesion!

I don't think this is necessarily true. Based on my experience with it, I recommend rear toe-in at the minimum end of the spec range for the novice, and recommend against more than ~0.5deg total.

In my experience I get rear tire life on the order of 2/3 front tire life running minimal rear toe (.15-.30 degrees total), and I got 1/4 the rear tire life at 1 degree total. I had already suspected something was BAD wrong with the rear toe due to twitchy the on- and off-track behavior of the car (suspected too LITTLE rear toe, actually!), but getting less than 3k on a set of Dunlop Sport Maxx TT's when I'd normally get 6k+ on Star Specs, I KNEW something was indeed WAY off.

Don't see why excessive rear toe shouldn't eat up tires any less eagerly than excessive front toe should (more so in fact as static front toe is zero).

IMO, Honda botched the AP1's suspension geometry with excessive rear toe change with bump, AND they botched the rear toe-in alignment spec on the high side as well. In this case, the second wrong probably doesn't help make up for the first one, probably makes it worse!

When I accidentally got 0.15degree total rear toe-in alignment, I *expected* the handling to be a bit more twitchy/oversteery, and was surprised that it wasn't. When I started noticing excessively twitchy/oversteery behavior, I suspected too little rear toe, but in fact it was due to too MUCH.

I used to subscribe to the "more rear toe => more stable/less-twitchy" theory, but my experience has been quite the opposite.

To the extent that I think novices are better off erring closer to the 0.15* total toe than 1* total toe. Beginner/novice, I say aim for [edit]~.3 - .5 degrees total. Experienced, take it as low as you dare (I aim for ~0.2* total, experienced no weirdness/instability at 0.05L/0.10R/0.15 total).

Bloodred

Wow, props for the educated reply

I realize this may be going a bit off topic, but I think the OP's question has pretty much been answered.

When the rear tires are toed in, the leading edges of the tires are pointing slightly inward, which would cause the rear of the car to want to travel in a straight line (resisting turns/understeering). With excessive rear toe-in, the rears would resist turning too much, causing the rear to break traction easily. I'm guessing this is what you experienced.

While your experiences may tell you that less rear toe creates more stable handling, the general consensus is that more rear toe in creates stability (understeer), while less rear toe makes the car more nimble/twitchy (oversteer). I tend to agree with the general consensus, since it makes more logical sense to me.

Were there any other factors at play in your situation? Did you change suspension or tires when you got the car realigned with less toe? If so, that may explain your experience.


Wait, before you said less toe made the car more stable (minimizes oversteer), now you're saying it minimizes understeer. I'm confused

There's a lot more in your post I don't have time to reply to right now, but I'll get to it tomorrow

ZDan

I've thought about this *a lot* since last year's unintended "excessive rear toe" experiment (blind experiment at that!).

Maybe partly, but the worst of it was the instability *in a straight line* under traction-challenged conditions of heavy rain and some standing water I experienced on-track at Mont Tremblant and on the way back home last year. On track, the back of the car was moving around like crazy on the straights, real white-knuckle stuff! Ditto during the drive back through Montreal. In both cases, rain was heavy and there was some standing water. I checked tread depths at the track because the car's handling was so uncharacteristically evil. Fronts were at ~8/32 tread depth, rears were ~3-4/32 (first hint of alignment problems, rear wear rate was on over 3 times front wear rate, should've been less than 2x).

In retrospect, what I think was happening was that in the grip-challenged, puddles-of-standing-water conditions, I was losing different amounts of grip at the two rear tires at different times. Lose grip at the left rear and the toed-in right rear pushes the back of the car to the left. Regain left rear grip and/or lose right rear grip and the back end gets pushed back to the right.

The sensation was VERY much like a rear-steering mechanism inputting a set amount of left or right rear-steer randomly!

With LESS rear toe-in, this pseudo-random rear-steer phenomenon is GREATLY reduced! Which is exactly what I've experienced on worn tires and even track tires in the wet with the S before, with much less rear toe. There's just less grip, the rear isn't moving around on you all the time.

I also agree, but only to a point! And that point is, I'd bet, a lot closer to 0.5* than to UK-spec rear toe (which is 0* 40", or 0.67*, right?).

No other changes. I time trial in Showroom Stock A with COMSCC, which doesn't allow *any* changes (not even the front sway bar which apparently SCCA autoX does allow).

Actually, the excessive rear toe DID cause massive understeer in cornering. At the Mt Tremblant event in the pouring rain I'd come down the straightaway with the back end absolutely dancing around on me at high speeds, then brake for a corner (particularly the double-apex right at the far side of Mont Tremblant), turn in, and the car absolutely did NOT want to point in to the apex! Understeered like a PIG when I WANTED the car to point, and alternately pointed left and right continuously down the straights! It was an interesting day at the track, to be sure...

FTR I've driven this car and my 240Z many times in wet conditions on DOT-R tires with less water-channeling capacity without anything like the kind of schizo behavior the S exhibited that day.

At the next event, in the dry at Watkins Glen, after I'd scrubbed in the new rear tires (needed prematurely due to accelerated rear tire wear, which was due to excessive rear toe), the car handled fine, btw. But for the first couple/few laps, the back end would step out a bit under normal trail-braking into turn 1.

On my commute, in the dry, though, at highway speeds going over asymmetric bumps and potholes (i.e., one rear hits it other rear doesn't), I could feel the back end moving around. Kinda spooky...

Then when my NEW rears were gone after less than 3k miles (only the ONE track day on them, btw), that's when I had them check the alignment and found it was so ridiculously far out (~0.45*L, ~0.60*R).

Again, 0.15* total rear toe feels TOTALLY stable and predictable (while giving great "pointability" in cornering). Rear toe just over 1*, however, was spooky as hell in traction-challenged conditions even in a straight line (or maybe *particularly* in a straight line), and understeers like mad when you WANT the car to turn.

Rear toe-in is stable *if* both rears have the same continuous amount of grip available. The left rear pushes to the right, and the right pushes equally to the left. But as soon as one of the rear tire becomes loaded or unloaded relative to the other (as over a bump or pothole), or loses grip relative to the other (one rear hydroplaning or encountering a sandy spot), then you get some rear-steering which feels QUITE unstable!

This effect is minimized by running less rear toe-in.

In my estimation, based on street and track experience at three settings (0.15, 0.55, and 1.05 degrees total rear toe) is that rear toe in the 0.3 - 0.5 degree total range is appropriate for novices, and down to 0.15 or maybe even less is not a problem for experienced drivers, and that over 0.5* total is, in my opinion, excessive rear toe.