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Need your advice on tire setup

cobrarob

11 Shelby GT500
541
126
new york
Hey guys, been running my car with the stock SVT wheels w/ super sports,I have a set of SVEs w/285/35r18 Nitto 555II(square) for the track. Guess I'm nervous running squared over staggered
so I haven't run them hard on the track! Should I stay with them and adjust the suspension for the square
setup or look into a staggered R compound tire(275/40-305/35 NT01)?
Any advice? Thanks
 
I'm running the NT01's in the fitment you show and like them a lot. I just ordered another set. That's what you see in my signature photo. I'm planning on staying with a staggered setup for now. The 10" wide wheel you have is a bit narrow for the 305's but it will work. If your NT05's aren't the 555R II's then I think you'll be disappointed with them compared to your PSS tires.

@Wingrider
 

cobrarob

11 Shelby GT500
541
126
new york
Thanks Rick for the reply, they are the 555r II, I read that you were runnin those
and also seen that you were thinkin of goin square. Didn't know if there
was an advantage of goin square other than rotation of tires. Car has a lot of power
with the SC and worried about the increase oversteer!
 
My car feels very balanced at the moment so I'm sticking with staggered. You'll need to make some suspension changes to go square, especially with all that power. Are your 555's new? If so and since Nitto doesn't make those tires any longer you could run NT01's on the rear with them in the 305/35/18. I think they're similar enough that it wouldn't be an issue.
 
Dont be too worried about running squared, just build up your speed and confidence in intervals and dont go all out!

Not sure if you've seen this thread, but it may have some information that might be helpful to you.

If you have adjustable shocks, I'd set the rears a few clicks softer than the fronts, which should compensate for the square setup a little bit. I also recommend going with a smaller rear sway bar, but it's all based on your setup.
 

cobrarob

11 Shelby GT500
541
126
new york
The Nittos are new think I got the last ones off Discounttires.Rick your car looks good with that wheel/tire setup, maybe look into those and try to get rid of mine. I met Hermes up at Watkins and he was runnin the Nittos in 275/35-305/35 on 18x10s and looked nice also! These cars are a lot of fun but get ya a littl coocoo...lol
Thanks FDSako seen that post and had already bought the 18mm rsb(in garage)and I have the fr adj.fsb on the car now just in case. Not sure when my next trackday will be so I got a littl deciding to do.
Thanks for the help
 
5,017
5,846
I understand the wheel width concerns but IMO the 275x18 tires are really way too small, we had to run them in IMSA and it was always a challenge to get them to hook up. In PWC we run a 305/660/18 in front and a 305/680/18 in the rear (as I recall), unfortunately the difference in tire construction between these two is night and day. The fronts have very soft sidewall and the rears very stiff..which leads to it's own challenges. On the GT2 SCCA car we run 315 /18 Hoosiers on a square set up which works quite well, but you have to pay extra attention to the front wheel spacing., The T2 cars run 295/18 square.
I would not be afraid of running (or not running) a "square" setup, you are going to do what you need to in order to get the car to handle either way, but I'm fonder of a larger tire on the rear because what they do best is accelerate, so anything to enhance that is a plus, this does lead to some pushiness in the front, which is just sort of a mustang trait, but it's not excessive and it can be mostly dialed out with a good adjustable shock.
FWIW
 

Wingrider

'11 GT500, 99% Track Car. Lots of mods & I coach
NFSBOSS said:
I'm running the NT01's in the fitment you show and like them a lot. I just ordered another set. That's what you see in my signature photo. I'm planning on staying with a staggered setup for now. The 10" wide wheel you have is a bit narrow for the 305's but it will work. If your NT05's aren't the 555R II's then I think you'll be disappointed with them compared to your PSS tires.

@Wingrider

Whuh huh? My handle here. I have Pirelli 305/645/18 DHs stuffed on my 9.5 wheels but have 10.5 wide wheels coming.
 

cobrarob

11 Shelby GT500
541
126
new york
blacksheep-1 said:
I understand the wheel width concerns but IMO the 275x18 tires are really way too small, we had to run them in IMSA and it was always a challenge to get them to hook up. In PWC we run a 305/660/18 in front and a 305/680/18 in the rear (as I recall), unfortunately the difference in tire construction between these two is night and day. The fronts have very soft sidewall and the rears very stiff..which leads to it's own challenges. On the GT2 SCCA car we run 315 /18 Hoosiers on a square set up which works quite well, but you have to pay extra attention to the front wheel spacing., The T2 cars run 295/18 square.
I would not be afraid of running (or not running) a "square" setup, you are going to do what you need to in order to get the car to handle either way, but I'm fonder of a larger tire on the rear because what they do best is accelerate, so anything to enhance that is a plus, this does lead to some pushiness in the front, which is just sort of a mustang trait, but it's not excessive and it can be mostly dialed out with a good adjustable shock.
FWIW

Thanks Blacksheep for your input. I already put the 188mm rsb on the car
and I'll trying out the 285/25 square as mentioned above. If those tires you mentioned were the other way around ie the rears were softer would that had made it better? I'm not gonna ask about your 315 square feel cause your suspension is totally diff than mine...Lol Thanks again Rob
 

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