So why don't 10in wide square setups work?

[Norm Peterson]

And I am trying to get the point across that if sharp cornering response and steering precision is what you're chasing - he's absolutely correct.

"Optimum" cannot have a single definition once you're considering more than one aspect and assign different weight to each aspect than somebody else does. But if you really are putting performance first, you have to accept some sacrifices in other areas.

It's OK to dial back to a less-extreme-performance compromise point if you don't like the look or aren't as demanding, as long as you recognize that some performance is being left on the table by doing so. Here, it's just that your preferred compromise is different from mine and apparently Jim's, and occasionally a little different from what gets fitted as OE.


Norm

 

[Mach2burnout]

Yeah opinions do vary and so do results.


Sent from iPhone

 

[BigBlue05]

I'm thinking of putting some 295/35r18 PSS's on a square set up. I'm using 07 GT500 wheels, so a +45 offset. I also have some 5mm hubcentric spacers if I need them. I've been doing some research and it doesn't seem like I'll have any fitment issues. Anyone with more experience think otherwise? Any help would be greatly appreciated.

 

[Boaisy]

I had ET43 offset 18x10's with a tire that size. It was a VERY tight fit between the front shocks and tire. Maybe an inch of clearance at the most, maybe less. Didn't have issues on the track in terms of the tire/wheel contacting the suspension though.

 

[Norm Peterson]

The GT500's 9.5" wide wheel isn't wide enough to be running 295/35's (greater amounts of sidewall flexing and heat generation are involved just driving down the road). Actually, 18x9.5 wheels are already a bit marginal for running the GT500's own 285/40-18's (9.5" is the minimum for that size).

Your tire to strut clearance is getting too close for me to call even with 5mm spacers - wheels that are narrow compared to the tire size allow more lateral tire distortion. I don't know how far up toward the top of the tire that distortion will extend in your proposed setup, and I'm only seeing you having about 2mm strut clearance. For reference, I've got a maximum wheel width setup that still needs a little more than 1.2mm strut clearance . . . with the disclaimer that the specific struts you're running vs mine probably matter by more than that.

Do you have a backup plan if 5mm spacers aren't quite enough?

FWIW, you really should have 10 full turns of thread engagement at each lug nut, so plan on getting the longer (and stronger) ARP studs if you need to use your spacers.


Norm

 

[Pentalab]

The GT500's 9.5" wide wheel isn't wide enough to be running 295/35's (greater amounts of sidewall flexing and heat generation are involved just driving down the road). Actually, 18x9.5 wheels are already a bit marginal for running the GT500's own 285/40-18's (9.5" is the minimum for that size).

Your tire to strut clearance is getting too close for me to call even with 5mm spacers - wheels that are narrow compared to the tire size allow more lateral tire distortion. I don't know how far up toward the top of the tire that distortion will extend in your proposed setup, and I'm only seeing you having about 2mm strut clearance. For reference, I've got a maximum wheel width setup that still needs a little more than 1.2mm strut clearance . . . with the disclaimer that the specific struts you're running vs mine probably matter by more than that.

Do you have a backup plan if 5mm spacers aren't quite enough?

FWIW, you really should have 10 full turns of thread engagement at each lug nut, so plan on getting the longer (and stronger) ARP studs if you need to use your spacers.


Norm

A 295 tire is too wide for a 9.5" rim. H+R specs a min of 11 full turns of thread engagement. The max you can go without using new arp studs is just a 3mm spacer. A 275 tire would be a better fit for the 9.5" GT-500 rim....and end up 275 wide. A 285 tire will end up 280 wide.

A 285 rear / 275 front would be optimal...but then you can't rotate.
A 285 square setup would also work.
A 275 square setup would work superb.

 

[dark steed]

A 275 square setup would work superb.

I'm going with this! Square setup, thanks to good advice from you guys!

On a side note, the NT55R is apparently on national back order in 275/40/18!
I apparently got Discount Tires last set and they won't be in until next week. Arghhhh

 

[BruceH]

I'm going with this! Square setup, thanks to good advice from you guys!

On a side note, the NT55R is apparently on national back order in 275/40/18!
I apparently got Discount Tires last set and they won't be in until next week. Arghhhh

I've done a 275 square setup before. Worked great except for the tramlining on the rutted highways around here. The tramlining was so bad that I only kept them on for a few months. Being pulled all over your lane is unsettling to me. Tires were Hankook Evo 112. Very good tires for the road, super quiet, good grip.

 

[ford20]

I was looking at getting the Boss 302S BBS wheels in 10.5" and running some 295's on them. If I am understanding correctly 295 on a 10.5" wheel is still in the optimum range since I can't seem to find a sticky tire that is a 305/18 wheel. From what I can find, the Pirelli Trofeo R's are 295/30/18 which is 25" tall compared to the factory 27" tire height.

Would this be a bad size to go with in terms of adverse effects?

 

[Norm Peterson]

I've done a 275 square setup before. Worked great except for the tramlining on the rutted highways around here. The tramlining was so bad that I only kept them on for a few months. Being pulled all over your lane is unsettling to me. Tires were Hankook Evo 112. Very good tires for the road, super quiet, good grip.

If I'd heard this sooner I'd have advised you to try tinkering with inflation pressures and toe. Any static toe-out is twitchy to begin with, and even zero toe can be.


Norm

 

[Norm Peterson]

I was looking at getting the Boss 302S BBS wheels in 10.5" and running some 295's on them. If I am understanding correctly 295 on a 10.5" wheel is still in the optimum range since I can't seem to find a sticky tire that is a 305/18 wheel. From what I can find, the Pirelli Trofeo R's are 295/30/18 which is 25" tall compared to the factory 27" tire height.

Would this be a bad size to go with in terms of adverse effects?

Are there any situations where you would not have to be making an upshift, like to 3rd gear at autocross or 6th gear on a fast road course? What's the axle gear ratio?


Norm

 

[ford20]

Are there any situations where you would not have to be making an upshift, like to 3rd gear at autocross or 6th gear on a fast road course? What's the axle gear ratio?


Norm

That's my problem, I don't know to be honest what the shift points would be but I have 3.73's. My engine blew a month before my first planned track day and I haven't been able to figure it out. With the new engine setup, I don't know how that would play into my driving habits and shift points. I did look at this when I was debating the Trofeo R tires or the taller MPSS.

http://www.teammfactory.com/gearcal...annytype=&tranny=Calculate+Transmission+1+&+2

It seems that the MPSS would allow me a higher MPH although without knowing shift points, I would assume that this information might be useless. That is making me think that the extra grip of the Trofeo R's would be a good starting point over the MPSS despite the extra MPH in each gear.

 

[BigBlue05]

The GT500's 9.5" wide wheel isn't wide enough to be running 295/35's (greater amounts of sidewall flexing and heat generation are involved just driving down the road). Actually, 18x9.5 wheels are already a bit marginal for running the GT500's own 285/40-18's (9.5" is the minimum for that size).

Your tire to strut clearance is getting too close for me to call even with 5mm spacers - wheels that are narrow compared to the tire size allow more lateral tire distortion. I don't know how far up toward the top of the tire that distortion will extend in your proposed setup, and I'm only seeing you having about 2mm strut clearance. For reference, I've got a maximum wheel width setup that still needs a little more than 1.2mm strut clearance . . . with the disclaimer that the specific struts you're running vs mine probably matter by more than that.

Do you have a backup plan if 5mm spacers aren't quite enough?

FWIW, you really should have 10 full turns of thread engagement at each lug nut, so plan on getting the longer (and stronger) ARP studs if you need to use your spacers.


Norm

Thanks for the input Norm! I'm already running a square 285/40r18 set up for the road and for autocross. My 5mm spacers are on the car now, all 4 corners and have about 14 to 16 turns. I've been running them for years now. I'm on Koni sports. I know the 295s will fit the wheel, I'm just more worried about hitting the strut.

 

[ford20]

Has anyone ran 19x10.5 +45 wheels before in the front? I'm trying to figure out if they will work or not up front.

 

[Lucky_13]

I do, with a wide 305 (AD08R - 305/30R19).

Right now I have the CorteX JRi offset front coilover, so I don't need to run a spacer. But before I had KW V3s, and the package fit fine with a 1/2 inch spacer (also with a 5/8) and about 2 degrees of negative camber, could probably get away with a bit less. I have extended ARP studs.

 

[Lucky_13]

^this is with the KW's and the spacer, full compression on a decreasing radius sweeper (HPDE)

 

[ford20]

Oh wow this is a perfect answer! That is good news then!

So I will grab some CC Plates, some 1/2" spacers and grab the FRPP hubs for shits and giggles and it should be fine at that point I take it.

 

[Lucky_13]

Yup. I'm trying to recall accurately, but I think Filip at CorteX originally sent me the 5/8 (Maximum Motorsports) spacer vs. the 1/2 inch because the 5/8 had enough material to become hubcentric, or something to that degree. I've never had a problem running a MM spacer in any width on track, and I have them from 3mm all the way to that 5/8.


Noticed they have it up on the website now as a package deal:

http://cortexracing.com/product/large-wheel-fitment-kit-2005-2016-ford-mustang-front/

For the record, I use "Monster Lugs" (http://www.mackin-ind.com/portfolio/monster-lug/) and they've served me well over two seasons and 10+ HPDE weekends.