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wheels and tires fitment guide

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hey guys,

i need your help in knowing the following:

1. whats the widest tires front, and widest rear tires which i can put on my 2013 mustang boss 302 ?
(my car has the oem wheels of a 2013 regular boss 302, 9 inch front and 9.5 back)

2. whats my reference to the tire size range which i can put on any specific wheel ?

3. considering for circuit racing / drag racing ... is the exeptions for tire size range ( i can go wider or narrower) to the tire range if im racing on a str8 line or turns ?

4. what are the cons in circuit racing if i go over or undersized tire width ?

5. what are the cons in drag racing if i go over or undersized tire width ?
 

Bill Pemberton

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You are quite limited in tire size and I would recommend getting a set of squared Apex rims ( save you a ton of weight too as those are heavy rims) in 18x10s or 18x11s, as this will give you a broad range of competitive tires to use. Contact Apex at their site linked on the sidebar of this Forum.
 

ArizonaBOSS

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+1 to what Bill said.
For road racing, these cars need as much tire as you can afford, and square setup.
You can get a 315/30/18 on an 18x11 no issues (what I run), which is about as wide as you can go with tires on these cars before having to do bodywork.
 
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the problem here is not the wheels.. im facing a problem with finding tires... and im really struggling with the tires and tire size.. here we dont have a big range of tire and sizes

even for the 18x10 or 18x11 ... please help me figure out the things i would like to know to have an idea of tire size range in comparison to wheels .. and the oversized and undersized wheels i would like to get this kind of knowledge so i get the idea for future

many thanks for the support gentlemen ,, im glad to be a TMO member
 

Bill Pemberton

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Since you are not sure about tire size and how they compare to the rim size, you might use the resources at www.tirerack.com. There is a link on the Forum page quite often and you will be able to check a tire, see what sizes it comes in, and then click on the word , Specs, and it will give you what you are asking , a range of widths a specific tire will fit.

Let us know what tires you have available and you may have the option of getting tires from Europe or the United States. I know we used to send Hoosiers to one of our customers in UAE, though I imagine that is quite expensive?
 

Apex Wheels

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Ask and you shall receive: https://support.apexraceparts.com/h...5526493-S197-Mustang-Wheel-Tire-Fitment-Guide

As the above guys mentioned, 11" front wheels when combined with extended wheel studs and a 20-25mm spacer is the hot ticket for track use. Both 18" and 19" offerings work well, mainly comes down to what tire you'd like to run. Generally speaking, 275-285 is perfect on a 10" wide, and anything from 295-315 works well on an 11" wide. Personally wouldn't consider anything smaller than a 275 tire on these cars.

The "cons" of going undersized would be of course less grip. But this can also lead to understeer, and in turn more tire wear (shoulder chunking, etc).

- Cory
 
This (https://www.wheel-size.com/calc/) is the best tool I’ve found for sizing wheels and tires on any vehicle. It’s free, easy to use, and you can crawl over your car with a tape measure and enter the info. You can see before you order exactly how the set-up you choose will fit.

18’s will always be the more popular choice, if for nothing else than weight, tire option, and cost.

19’s are a good option for style, as they will fill up the wheel well and still perform better than your OEM wheels, because the offerings from Apex are lighter, stronger, and wider.

Really, the decision I struggle with is square vs staggered. A squared setup will be easier to live with daily due to the ability to rotate from front to rear. A staggered setup is the impossible cool, however.

Good luck, and let us know what you decide. Preferably with pics.
 
+1 to what Bill said.
For road racing, these cars need as much tire as you can afford, and square setup.
You can get a 315/30/18 on an 18x11 no issues (what I run), which is about as wide as you can go with tires on these cars before having to do bodywork.


Why do these cars “need” a square setup? Is it an understeer issue, or something else?

I love a staggered setup, and I want to go that route, but don’t want to compromise on performance.

Feel free to correct me if I’m wrong, as I admittedly don’t know everything about this car and how it performs on the track, but I would think that moving from OEM to, say, a 19x10 F and 19x11 R would still show a great benefit traction wise, and not change the handling characteristics or balance of the car too much from stock.

What has your experience been?
 

ArizonaBOSS

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Staggered to 1) prevent understeer and 2) ensure you can rotate your very expensive race tires to get the most out of your money.
 

JDee

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I have 10" front 295/30 and 11" rear 305/30, these 295s run as wide as a lot of 305s. It is a big upgrade from OEM but even with that its terminal cornering state is push, or understeer. It's a front heavy car and there's less tire on the front than the rear to carry that weight. I can drive around it, but I know I am sacrificing g's.

I'm not racing, but I am trying to get the most I can out of the car and I know with the staggered setup I'm not there. I'm not sure working on spring rates/sway bars/shock settings could cure this either, certainly not cheap to do it that way, so it just seems the easy button is more front tire. So this year we're going square 11" 305/30s, have everything installed and ready to go, just waiting for the snow to disappear to road test things.
 

Bill Pemberton

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AZ Boss's notation above should read Squared, not Staggered. Just a little slip, but he will probably take it in stride, though being corrected by an old racer on Social Security may tick him off, ha,ha!

Seriously, just a typo, and I have done far worse , but his answer is simple and correct! AZ Boss is my hero, so got to tease him a tiny bit once in awhile!
 
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ace72ace

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So I have gone square with Boss LS 19x10s and Kumho AS 285/35/19s. So very happy to get away from the summer only tires living in NH. Given that the car came OEM with smaller tires up front, would it be a good idea to have the factory front end alignment adjusted to account for the wider width tire?

This is all stock OEM front end, no racing components installed. My Boss will continue to be a street car for the next several years, which is why I picked the all season tires. My guess is that I will be fine just having the alignment done to factory specs but figured it wouldn't hurt to ask here.
 

Norm Peterson

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If you're at all inclined to drive the corners with much, ummm, enthusiasm . . . you might want cambers set closer to the negative end of the factory range than at "factory preferred" which lies right in the middle of a pretty wide range.

Seriously. Factory max-negative is probably -1.5° just like it's been for other S197s. My own car has always been even further negative and is around -1.9° right now, with tire wear that's still more uniform across the tread than technically being that far "out of spec" might lead you to expect.


Norm
 

domesticpower

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Our cars (and most modern front engine rear drive cars like M3's, Camaro's, etc.) are heavy by track car standards and more of that weight is over the front axle. More weight means you need more tire, otherwise you sacrifice grip. There is also a lot of camber gain (without enough static camber dialed in) so narrower tires tend to roll over the tire shoulders which hurts grip and accelerates wear (a lot).
 
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I'm guessing its because 90% of Mustang owners do not take their cars on a road course and Ford probably doesn't want to hear complaints from them about tramlining.

The extra road friction may also affect fuel economy and thus their CAFE numbers.

I'm sure the bigger wheels, meat, and required spacers for the front would cost more. The extra camber that may be required to avoid rubbing may be an issue for tire wear. The open lug nuts and exposed studs may not be esthetically pleasing to the general public.

Finally, some states (like Pennsylvania) will not allow a vehicle to pass its annual safety inspection with the 1" spacers that would be required on the fronts. I think PA has a max of 0.25"

10" wide square may not require spacers or extended studs but some of the other issues may still apply, albeit to a lesser extent.
 
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19’s are a good option for style, as they will fill up the wheel well and still perform better than your OEM wheels, because the offerings from Apex are lighter, stronger, and wider.

If the overall diameter of the tire is the same, the wheel well will be filled exactly the same whether using 18" or 19". It basically depends what aspect ratio you prefer to get to that point along with available sizes for the model of tire you prefer.
 
If the overall diameter of the tire is the same, the wheel well will be filled exactly the same whether using 18" or 19". It basically depends what aspect ratio you prefer to get to that point along with available sizes for the model of tire you prefer.
I should have been more clear. I wasn’t meaning that the wheel and tire would be overall larger; you are correct that they are the same overall diameter. I meant the wheel opening would be filled with more ‘wheel’ than tire, which most find more aesthetically pleasing.

As far as your other post; define “tramlining” for me.

I don’t think Ford would have ran spacers from the factory. That’s too much liability. If they believed in a larger, wider fire up front, they would have made a hub assembly/wheel that maxed out with no need for a spacer.

Honestly, I’m still wrestling with a square vs staggered setup. All performance cars like as much tire as they can get. Yet, our Bosses were built for road racing according to Ford. They know a thing or two about making a car go fast around a track, as we’ve all observed over the years. I’m just curious of the logic around the decision to stagger the wheels, when it seems to be the consensus that square is better. Why not save some money and run two 9.5” wheels instead of engineering a car around a 9” and 9.5”?

It’s suspicious.
 

JDee

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Spacers of any size are banned in Ontario, if you get caught with them on a public highway they can pull your plates on the spot. The province's safety certificate guidelines show that as an instant fail. They will however, let you run those adapter thingies. Now that is some damn bizarre thinking and it was all driven by the ricer crowd who did absolutely insane things with their "cars". Regardless of this, I still run to and from the track with them on, though I do tend to perspire a bit heavier when I see John Law in the vicinity. :)
 

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