Rotatable GT350 Square Wheel-Tire Setup

[VoodooBoss]

I just put in two track days with my new square setup and the car felt better balanced than with the stock staggered setup. Very neutral front/rear balance and stable during high speed transitions. I did not make any changes to the suspension. Here's my setup and let me know if you have any questions:

@Need4SpeedMotors
@bpracer
@modernbeat
@CSL
@ChopSui
@JAJ
@scmscout

4-N4SW Project 6G 19x11 +50 rear wheels
4-Michelin Pilot Sport Cup 2's in 305/30/19
2-25mm front spacer
10-ARP 14mm x 1.5 front wheel studs with stock wheel studs in the rear, part number 100-7733
20-Dorman 611-257 open lug nuts (you'll need a thin walled socket)

Each wheel/tire is 52 lbs while the stock wheel/tire is 62 rear and 61.5 front. That's a 10 lbs saving per corner in the back and 8 up front with the spacers. Not as light as the CF R wheels but not as expensive either.

Front wheel with spacer


Rear wheel with Dorman lug nuts



Spacers


Torture tested

 

[JAJ]

That sounds great! Which 305/30x19 PSC2's did you get - I can't see the load rating on the sidewall in the picture. There's the "shaved from the factory" Ford spec tires (98Y) and the Porsche N0 (102Y) tires to choose from. I say "shaved from the factory" because he Ford tires have about 50 thousandths of an inch less tread depth than the Porsche tires when new. When I got my set of PSC2's, I had to go out of my way to make sure I got the Ford tires. The other difference is that the Ford tires are made in the USA and the Michelin website refers to them as the "Latest Generation", whatever that means.

 

[VoodooBoss]

They are the non Porsche tire made in the USA.

 

[CSL]

Thanks for sharing. Curious if you noticed much of a difference in your shift points with the 305/30, and if any extra low end was noticeable tracking out with the shorter tire? My 305-315 stagger was also very neutral without any notable understeer. It would only show itself if you deliberately tried to induce it.

With the stock 305/35s I am at the ragged edge with my third gear shift points in a few places at one of the tracks I run. I haven't been back there yet with my 315/30 Cup2s, but I think it may screw up my winding it up to 8k in a few places. I'll find out soon enough.

 

[VoodooBoss]

It accelerates a bit crisper than with the stock tires. The shift points did change slightly but for me it was to the positive. I mostly run Sonoma and Thunderhill and the shift points are now nearly identical to my Boss 302 so from a familiarity point that's a good thing. At Thunderhill I'm not shifting into 5th on the front like I did with my Boss. I have a gear ratio spreadsheet and with the 30 series tires and taller gearing I'm able to stay in 4th and wring it out. Send me a PM with your email address if you'd like me to send it to you.

 

[BigTaco]

It accelerates a bit crisper than with the stock tires. The shift points did change slightly but for me it was to the positive. I mostly run Sonoma and Thunderhill and the shift points are now nearly identical to my Boss 302 so from a familiarity point that's a good thing. At Thunderhill I'm not shifting into 5th on the front like I did with my Boss. I have a gear ratio spreadsheet and with the 30 series tires and taller gearing I'm able to stay in 4th and wring it out. Send me a PM with your email address if you'd like me to send it to you.

Did you recall your speedo or rather have the dealer do it?

 

[bpracer]

Do you think the 315-30 would work all the way around?

 

[VoodooBoss]

Do you think the 315-30 would work all the way around?

I think so. With my setup I have about 17mm between the wheel and strut. I thought about getting a slightly thinner spacer but kept it that way in case I wanted to run the 315's. I probably won't do that as I'm not worried about and don't keep lap times so the extra width isn't going to matter to me. @Black Boss was running Hoosier R7's in 315/30/19 square on his R with the stock CF wheels. Personally if I was worried about dropping lap times I'd get Hoosier R7's or Pirelli Trefeo R's. More on the Trefeo R's shortly.

Did you recall your speedo or rather have the dealer do it?

No I didn't. I'm not worried about the speedo on track and very rarely look at it. I do check temps and RPM's on track though.

 

[VoodooBoss]

Third day on these tires with two rotations on the rear and one up front.

 

[AMPowerJ]

What camber settings are you using?

 

[VoodooBoss]

What camber settings are you using?

I'm using -1.8. For my style of driving it seems about right. I had another track day today and I'll pull my wheels off this weekend and snap another photo

 

[VoodooBoss]

Finally found wheels that will clear the GT350 front brakes with room to spare.

 

[TMSBOSS]

Do they come in pink??

 

[dirtroadtrip]

Thanks for sharing your setup! Do you have a link to where to get the ARP studs and 25mm spacers?

 

[VoodooBoss]

Thanks for sharing your setup! Do you have a link to where to get the ARP studs and 25mm spacers?

I purchased the custom made spacers from Motorsports Tech and the 14mm wheel studs from Optimum Performance.

http://www.opmustang.com/store/p99/store/p99/ARP_14MM_Extended_Length_Stud_5_Pack_2015__Mustang.html

http://www.motorsport-tech.com/wheel_spacers.html

 

[gleek48]

Thanks Rick. I will keep an eye out for the 14mm studs. Was it a custom made/fitted spacer?

 

[VoodooBoss]

Thanks Rick. I will keep an eye out for the 14mm studs. Was it a custom made/fitted spacer?

Yes they can make them any size you want. They are hub centric and I paid $20 extra to have the holes drilled which dropped almost a third of a lb from each spacer. Great service too.

 

[VoodooBoss]

Finally getting to an update after my last track day in September. Tires after two days on the front and two on the rear. I've dropped hot pressure to 34 lbs and have -1.8 degrees of camber. At 34 they stayed very consistent throughout the session and my last track day was 100 degrees ambient for the last session of the day. Everything else is stock. One more day should be no problem and I'm hopeful to get two more days out of them. They are wearing very evenly and I'm just barely above the wear bars. These tires have at least 500 track miles and approximately 1,600 street miles on them.

 

[viva_brasil]

Planning on running basically the same setup - will order another set of non-R rear wheels and run them on the front with a spacer. OEM non-R wheel is $530-ish. Trying to find the studs and open lugs that work with the OEM wheels.

 

[VoodooBoss]

Planning on running basically the same setup - will order another set of non-R rear wheels and run them on the front with a spacer. OEM non-R wheel is $530-ish. Trying to find the studs and open lugs that work with the OEM wheels.

I'd look for other wheels that are lighter. HRE FF15's are very light at 23 lbs each and available from N4SM. You can find the stud and lug nut info at the link below.

https://trackmustangsonline.com/index.php?topic=11405.0