Can you explain to me how a wider rear tire (in a staggered configuration) would compromise emergency maneuvering, stopping power, wet handling et al? I just have a different understanding, but I realize that I am not well-versed in tire physics, and in the above mentioned threads, you have demonstrated a great deal of knowledge on the subject. I appreciate anything you can share.
I'll try, you can decide how successful I am.
First a few basics (note all numbers are done for ease of math only):
1. Contact patch area depends on the air pressure and the load, so a 1000 lb. load on a 50 psi tire gives a 20 in[SUP]2[/SUP] contact patch.
2. The width of the tread determines how long the contact patch is. A tire that has a tread 10 inches wide will have a contact patch length of 2 inches.
3. A wide but short contact patch gives a higher g-force than a narrow but long contact patch.
4. A narrow but long contact patch gives more acceleration and braking traction.
5. A narrow but long contact patch will slip sideways less when going over an expansion joint or other road irregularity during a turn.
6. Ideally the road pressure on the contact patch is even throughout the contact patch. This is usually not the case and some tires have a more even contact patch pressure than others.
Tires have what's know as slip-angle. This isn't a very good term because the tires don't actually slip. A tire on ice would slip (sideways) but then the slip-angle would be zero. What the slip-angle is is the difference between a line drawn through centre line of the wheel and a line drawn through the centre line of the tread (in the rolling direction). As the profile gets lower the slip-angle is reduced. If the tires have different slip-angles front to rear then the car will either tend to push the front out (understeer) or push the rear out (oversteer). An extreme example of what happens with different slip-angle tires that many people have experienced--in North America, other places don't allow silly stuff like this--is putting on only two snow tires and the car becomes squirrelly even at low speeds on dry pavement.
If the tires on the rear are wider than the tires on the front but the weight is equal and the pressures are equal, then the rear tires will have a higher g-force than the front tires. The slip-angle will be different too (likely smaller but...) It's often not noticeable until you reach the limits of adhesion of the tires, and if you're not expecting it--and sometimes even if you are--or don't know what happens at the limit of adhesion the car can do some surprisingly nasty stuff. With a car that has an even weight distribution, like the Model S, having the same tires all around produces the same g-force front and rear and the same slip-angle so the behaviour is very predictable at the limits of adhesion. The problem here is that the vehicle behaviour can change suddenly at the limits of the tire's adhesion.
The other problem is that most of the above assumes all things are equal--with real-life-tires all things usually aren't equal or even close to equal. Belt construction, bead area construction, and tread compound are a few of the things that can be different. Even the same size and model of tire made in a different production run can be different if the tire manufacturer has silently
improved the tires. (Whether the tire purchaser thinks an improvement has been made is sometimes a matter for debate.)
Now you can have a reasonable amount of confidence by taking your car on a skid pad (best) or race track (can be almost as good) and pushing it (with the staggered tires) to the limits (actually you push it to just beyond the limits) to see what actually happens with the tires you installed (of course, it's also possible to flip the car doing this--unlikely with a Model S but probably not impossible). However, skid pads aren't that easy to find and access is usually limited. Also this kind of testing usually wipes out the set of tires being tested, so purchase a second set.
You can also rely on the electronics (VSC in particular) to get you out of trouble but it's best to have your vehicle set up so that you have a hard time getting into trouble in the first place. Electronics are good but they can't overcome the laws of physics.
As far as wet handling goes, there are two situations that happen: hydroplaning and viscoplaning.
A. Hydroplaning happens when the the wedge of water that builds up in front of the tire reaches the tire pressure. In our example above, when the wedge of water reaches 50 psi, the tires will lift of the pavement. The wider the tires are, the shorter the contact patch, and the lower the tire pressure, the sooner hydroplaning will occur.
B. Viscoplaning occurs when the tires slip on a slippery substance such as oil, leaves, pavement markings, etc. It can occur at any speed. It's most likely to happen during the first rain after a long dry spell as the water causes the oil to float out of the pavement irregularities.
The thing about low profile tires is that they are a wonderful cash-cow for the tire manufacturers. They wear out quicker and cost more than tires with a sensible profile. In most cases they also ride harder and are noisier as well. However, the public has been sold that wide low profile tires are better, give more traction, etc. which are half-truths at best. Low profile tires do provide crisper steering feel (except over that expansion joint where they slip sideways and provide a real nervous nelly moment) and a higher g-force at the expense of just about everything else (again, all thing being equal which they usually aren't).