A good solution if you only drive in a straight line. Lateral traction is substantially reduced, both with the narrower tires and the lower air pressure. Your setup is more appropriate for the dragstrip, less so for the twisties.

 

No. I definately have much better traction around a corner as well, than when I was running the 295's, by far. I think it has alot to do with the high camber. All four of my 295/255 tires wear very noticeably on the inside vs the outside of the tire, plus you can visually see the camber when you look at the wheels, which means there is a much greater force on the inside half the tire than the outside, which would imply that the quality of the contact patch is suffering as you move outward. Better downforce and contour across the whole contact patch with the 285 @ 29 psi. Now if you air down the 295 or 305 you night be able to achieve better results but that just doesn't leave much lower section height for the street, or if you reduce the camber you would make the patch more effective as well. I'm pretty sure if you look at the rear tire of a zr1 the camber isn't visually noticeable.

 

Oh and I ran the spacers on the 295 for a while before the 285, still had no rubbing, but still had terrible traction, so the extensions didn't play a noticeable part in the better traction, definately due to the larger overall contact patch.

 

Just keep in mind that the tire size numeric values don't really directly dictate actual tire size. They are general numbers but manufacturers will vary so you have to look at the actual tire size which Tirerack does display. Just ask an example, my race car uses 245 size tires. Those have a tread width of 9.7" in some race tires where I have other race tires of the same size from a different manufacturer that are almost an inch smaller for tread width. Same thing happens with street tires so when comparing grip/stability between tire sizes, if you are also switching tire manufacturers with the tire size it won't be a good comparison.

 

I totally agree, the numbers are somewhat generic in that regard and there will definitely be differences with various tire specs. But is generically safe to say that a slightly taller tire with more contact patch will most likely improve traction over a wider tire with higher pressure.

Really I'm just trying to show the math behind why I had such terrible traction on the (RWD) 295 and a huge very noticeable improvement when I switched to the 285 @ 29psi. I can only assume that what helps the RWD setup would aid the AWD as well since its rear bias.

 

Lower tire pressure, to a point, will increase acceleration grip on any tire. However, too low depending on the tire construction can cause other problems. Lower tire pressure also creates more rolling resistance which will generate more heat in the tire, slower top speeds, etc.. It just all depends on what you need out of a tire.

 

I have 15mm Eibach spacer on my F Type AWD 5V8 with Ceramics brakes. No issues at all.

 

I just put on 20 mm adapters all four wheels, (stock size tires and wheels).