shind3

I'm sure a square setup is faster since you can effectively add more rear grip by trying to 'balance' with a bigger front sway bar, but as far as handling balance, my car (stock springs/shocks) is unbelievably neutral with 225/255 RS4s with cheapo 30.5mm sway bars front and rear with toe settings of 0/0.15 degrees with camber in the range of 3.5/2.5. I suspect it has a lot to do with driving technique as I trail brake into corners 3rd gear and below. If the goal is to learn to how to drive a car with proper handling, a square setup isn't needed. I can make the car oversteer or understeer at will during any corner I have a long enough straight to get up to speed.

Though, I'm sure 255/315 will be faster still than 255/255

Bullwings

Once you put a GT wing on it, staggered ceases to be faster.

Front grip becomes the limitation.

Pretty much all of the top level time attack S2000s are running square setups with GT wings.
Arvou s2k is on 295 square.
All of the last Evasive time attack builds have been square setups, whether NA or supercharger.
Also, because of the 49/51 weight distribution, a square setup balanced with aero makes the best use of grip on both ends.

If staggered was faster, i'm sure they would run staggered. As it is, a staggered setup with a GT wing is going to be understeer all day, followed by snap oversteer.

The other thing is tire availability. Compound will always beat width and contact patch.

I'm certain that a 255 square RE-71R or A052 setup with a GT-wing is going to be faster than a wing-less 255/315 NT-05 setup - that's a lot of extra unsprung weight and rolling resistance on an inferior tire compound. I would venture to say that even a wing-less 17x10 255 A052 square setup will be faster around a road course than a 255/315 NT-05 setup. The newer tire compounds are just that good.

Back in the day, I believe some data was collected to say that:
-RS3s were 1 second faster than NT-05
-NT-01 was ~1.5 second faster than RS3
-RC1 is about equal to 0.2 second faster than NT-01 in cooler weather
-Fresh RE-71r is faster than RC1 and NT-01 by about 0.2 to 0.5 seconds
-All at Buttonwillow CW13 with 255 square setups with GT-wings

-and finally, some other data out there is saying A052 (also a BS TW200 tire) is slightly faster than RE-71R

Everything else being equal (even aero), I don't think an extra 65mm of rear tread contact is going to over come ~3.5 seconds of newer tire compound advantage...

Mrsideways

Looks similar to mine with lack of rear travel.

s2000Junky

Generally agree with you here. I cant confirm all the tire compound variables becuase i havent tested them myself but generally sounds about right from whats been posted from others. Thats said, keep in mind aero only comes into play at a high enough speed, bellow that we are relying on purely mechanical grip. Also some of us choose to street our track cars and choose to run top down with no rear wing becuase its more fun. That said, I wish some of these other tire compounds came in larger 315 17" sizes so I could take advantage of some of the newer technology. Will have to be satisfied with NT 05/01 and R888R until then. There is always a compromise one has to make in some regard to gain somehwere else.

Getting back to the OP, adding rear tire width to help control corner entry oversteer is still one of a few viable options.

bgoetz

s2000Junky

When you reach the bottom of the suspension stroke under laterial forces, the reaction is emediate loss of traction. You must tune tire grip to spring rate, but when you run out of travel you have effectively increased it ten fold and the reaction is loss of grip. It's forces of intertia, something has to give. So you either increase your up stroke travel or increase the spring rate to keep off the bump stops.