Wheel and Tire Plan For Gt350 Brake Swap

[SplawnDarts]

I'm looking at options for wheels and tires for a GT350 brake swap on a stock 2020 performance pack 1 car. I think I've slogged through wheels and tires and figured out what to get, but I'm hoping people here can point out if I'm doing something stupid.

Wheels: Apex EC-7 (they claim it's tested and fits - https://www.apexraceparts.com/blog/apex-19-ec-7-wheels-gt350-brake-clearance/ )
19x10" front
19x11" rear

For tires, I want the option to run Pilot Sport 4S or Pilot Sport Cup 2 tires. Looking at the available sizes, it looks like for the front 295/35R19 would work for either tire. For the rear, I'd use the same size 295/35R19 with the 4S (it's all that's available) but go to a 305/35R19 for the Cup 2.

Anyone see any problems with this?

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[SplawnDarts]

The more I look at this, the more it seems like the tires might be too wide for the bodywork? I'm really not sure how to tell for sure. The performance pack 2 runs 305/30R19 everywhere, right?

 

[Labradog]

Why not get a 350?

 

[SplawnDarts]

Why not get a 350?

Cost, and not the engine I want.

 

[Labradog]

But your looking at spending like 8k on brakes and wheels on a new car?

 

[SplawnDarts]

Yes. The question here is not what car you would buy. I'm sure you have an opinion on that, but it has nothing to do with what I'm asking. My question is about what wheels and tires would fit on a specific car.

 

[m3incorp]

Don't forget to also compare the offsets of the GT 350 wheels to the GT wheels. The tires will fit, if the offsets are correct. I don't see any mention of offsets in the article. They could very well clear the brakes but how do the look on the car? Are the roads good where you are, or would you have to worry about tram-lining from a 305 width tire in the front? Something to think about. Zooming in on the tire in the pic...it is a 275 width tire. A 305 is a significant size difference.

The more I look at this, the more it seems like the tires might be too wide for the bodywork? I'm really not sure how to tell for sure. The performance pack 2 runs 305/30R19 everywhere, right?

 

[SplawnDarts]

Don't forget to also compare the offsets of the GT 350 wheels to the GT wheels. The tires will fit, if the offsets are correct. I don't see any mention of offsets in the article. They could very well clear the brakes but how do the look on the car? Are the roads good where you are, or would you have to worry about tram-lining from a 305 width tire in the front? Something to think about. Zooming in on the tire in the pic...it is a 275 width tire. A 305 is a significant size difference.

The offsets are 40mm front and 52mm rear I believe. They have a fitment guide here I found:

https://support.apexraceparts.com/h...5483093-S550-Mustang-Wheel-Tire-Fitment-Guide

Front: 19x10” ET40 with 285/35-19 tires
Rear: 19x11” ET52 with 305/30-19 tires

• Popular fitment.
• Direct fit
• 275/35-19 front and 295/35-19 rear tires may also be used as a direct fit

So it looks like I went one notch too wide front and rear and should consider 285/35R19 and 295/35R19 instead.

I would expect some tramlining with a Cup 2 I would think? The Performance Pack 2s I've driven seem to have it.

 

[m3incorp]

On the aggressive fitment thread, I think there is a chart that shows the idea sizes for the 19" wheels based on offsets and the use or lack of use of spacers.

 

[SplawnDarts]

Cool, I'll go take a look. Thanks for your help!

 

[m3incorp]

No problem

 

[D Bergstrom]

I did a bunch of research on this a year or so ago when I was thinking about the GT350 brake kit for my GT. The brake kit on the front doesn't change anything, so standard S550 offsets are what you want. The Apex 19x10, 40 offset should work fine with a 285/35 tire. If you want to run a 295/35 tire, it will work also, but per Apex, you would need a 12 mm spacer or so. By my calculations, I think you could get away with a 5 or 8 mm spacer, but I would for sure double check that once I had the wheel and tire in my hands.

The GT350 brakes increase the rear track width by 1/4" on each side, so essentially the 52 mm offset wheel would become a 45 mm offset wheel. (For measurement purposes anyway.) I know a popular mod for PP1 cars is 1" spacers all around, so if you compare a 45 mm offset wheel with a 305/35 tire to an oem PP1 rear wheel (275/40, 52.5 offset) with a 1" spacer, the 305/35 mm combo will still be slightly narrower, so should still fit with no issues.

Doug

 

[Ewheels]

Yes. The question here is not what car you would buy. I'm sure you have an opinion on that, but it has nothing to do with what I'm asking. My question is about what wheels and tires would fit on a specific car.

I think he is only trying to save you some money. I'm sure the 350 brakes are better than the PP Brembos but I seriously doubt they are $4,000 better. Just get track pads/rotors for a fraction of the price.

To answer your actual question, as long as you stay with 19" wheels, you'll clear the brakes. Apex's fitment guide that you linked should give you all the info you need. If it helps at all, I have 19x10 ET 35 in the front with 285/35 tires without spacers and I still have about 13mm of space between the tire and the strut body.

I know it's not what you're asking for, but I would also advise against Cup 2s. Great performing tire but they don't last long. There are many other track tires that perform just as well, last longer, and are way cheaper (NT01 for a good example). I don't know anyone who tracks their car and uses Cup 2s

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