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Help me narrow down my tire size & wheel selection ...what are your thoughts?

Hi All,

I have a stock 2012 Boss in Competition Orange, with which I plan to do the following mods:
FRPP T springs. (Maybe Steeda Boss lowering springs)
LCA bracket.
Adjustable Panhard Bar.
Maybe UCA.
Maybe LCA.
DSS or FRPP aluminum drive shaft.
This is a summer daily driver car for me. I'm not racing and don't plan to, may try and get to a track day or two, maybe an autocross.
Decided on MPSS for tires.

Here are what I think are functional options that will lower the car slightly and level it out. I don't think any of these combinations will rub or cause any handling misbehavior.
What do you all think?

Option 1:
Forgestar F14's or CF5's 19" wheels
Front 275/35/19 w/10" wheel
Rear 305/30/19 w/11" wheel
This setup maintains the stock diameter difference of 0.3" and lowers the car 0.3".

Option 2:
FRPP 302S 19" wheels:
Front 265/35/19 w/9" wheels
Rear 295/30/19 w/10" wheels
This setup maintains the stock diameter difference of 0.3" and lowers the car 0.45".

Option 3:
FRPP 302S 19" wheels
Front 265/40/19 w/9" wheel
Rear 295/35/19 w/10" wheel
This setup maintains the stock diameter difference of 0.3" and raises the car 0.1".

Option 4:
FRPP 302S 19" wheels
Front 275/35/19 w/9" wheel
Rear 295/30/19 w/10" wheel
This setup increases diameter difference to 0.6" and lowers the car front 0.3" and the rear by .45".

Option 5:
FRPP 302S 19" wheels
Front 275/40/19 w/9" wheel
Rear 295/35/19 w/10" wheel
This setup increases diameter difference to 0.6" and raises the car front 0.25" and the rear by .1".

Please offer your thoughts, experiences and any concerns with these alternatives and also any advantages and disadvantages that you are aware of.

Thanks,
Ed
 
Go with the Steeda springs.

Skip UCA and aluminum DS for now.

LCA and relocation brackets.

18 by 10 or 10.5 wheels.
 

302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
2,009
439
Southeast
Go with the above recommendation, but since your not tracking the car, and it's a summer only DD, go with your Option 3 and keep the taller sidewalls. You'll get a much better street ride with the 40's and 35's.

Good luck and keep us posted.
Dave
302 Hi Pro
 
302 Hi Pro said:
Go with the above recommendation, but since your not tracking the car, and it's a summer only DD, go with your Option 3 and keep the taller sidewalls. You'll get a much better street ride with the 40's and 35's.

Good luck and keep us posted.
Dave
302 Hi Pro

HI Dave,

Could you comment on going to 275/40/19's in the front? What do I gain or lose by this?
What about Option 1, going big! Whats the gain or loose?

Thanks!
-Ed
 
I have 305/30/19 on 11" +53 forgestar CF5V. The wheels are great but the tire looks funny. Running stock 255/40 on the front and the front tire is a larger diameter than the rear. Honestly a 305/35 would me better but that size isn't common. I am looking at 325/30 next time.

I really wish I did 20's. At least in the back. It will fill the wheel well better. 325/30 MPSS's are about $415 a tire and that's just too much.

As yours is a DD like mine make sure you consider what tire and 20" rims.
 

Grant 302

basic and well known psychic
I'd go with option 1, and consider going up to the 285/35.

But frankly, I think any of those combinations work fine, IMO. I have the tendency to be greedy about grip...so option 1 makes the most sense to me.
 
further said:
Skip UCA and aluminum DS for now.
I agree with this. If it's a daily driver you'll get little benefit from these but more NVH.

I vote for opton 2 and that's what I have on my car. Note the 265/40/19 and 295/35/19 were not available when I purchased my PSS tires. I still might go for the lower profile but mine's not a DD.
 

302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
2,009
439
Southeast
12Boss said:
HI Dave,

Could you comment on going to 275/40/19's in the front? What do I gain or lose by this?
What about Option 1, going big! Whats the gain or loose?

Thanks!
-Ed

Hi Ed:

To begin, I don't think there is any wrong answer here, but rather my focus in recommending option 3 was based upon my understanding of your intended use of your Boss. That is to say, my impression was that you would use the Boss for 95% daily street driving and very little Track time. So for Street use, I would recommend you go with OEM sidewall specs and then increase the tread with by one size. This was my reasoning. You can also consider the following:

Tread-width:
The front suspension was designed to carry a 255 tread-width. You could bump up more than one size here, (i.e. 285/295) and this will provide much more traction. It also brings more lateral forces than your stock suspension was designed for. So in my opinion, it is not a good long term solution. Steering linkage, tie rod ends, bushings, etc., and even ball joints are subject to shortened expected life spans. Not to mention, your electronic steering system, (EPAS), is programmed to respond, (feel), with specific tire sizes.

Sidewall:
If you run a lower profile tire, you often find they are much stiffer. This increases tire performance, (traction), but it also increases the lateral forces that come with traction. Additionally, a 30 sidewall, depending on manufacturer, can be stiff to very stiff, (not all the same), which for street driving, makes for a rough ride under certain pavement conditions.

This is why I made my recommendation for street duty.

I will be the first to admit that all of this is boils down to personal taste, and driving habits, and or purpose of ones intended use for their vehicle, so again, there is no right or wrong answers given here by anyone. It just a matter of matching the right components, (tires/wheels), in this case, to fit the personal taste of the owners expectations.

I also think you can run 9.0" / 10.0" wide X 19.0" wheels for street duty. These are LS spec wheels and work well within the dynamics of our Boss and Boss LS suspensions.

If you want a more track capable Mustang, then by all means, wider / lower tires benefit the S197 platform, like 10.0 or 10.5 X 18 squared would be my setup. I would run as wide a tire as I could stuff in the wheel well. But I would do suspension and brake mods as well.

Again, this is just my opinion, and like I said, no real right or wrong answers here.

I suspect you will be happy with what ever size you end up buying. OBTW, I don't recall what Option you favor, so what are you leaning towards? Perhaps you should state your preference, then ask other Members how they like that particular setup.

Let us know,
Thank you,
Dave
 

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