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i currently have 18"s on my car, but the rims are the ugliest i've ever seen.. So I'm in the market for new wheels.i was thinking about 19"s to get a better look and still some good performance but the low profile tires look nice on the 20"s. i've read that the 18"s are best for the track for my car (2011 Mustang GT). It may be the tires i have but i can spin them 1-3rd gear if i launch it and even if i do a second gear roll. i currently am running some Nitto nt555 extreme zr. but anyways I'm just wondering what anyones opinions are and if anyone runs bigger rims and have any issues hooking up. is there a huge difference between rim size, and putting down power? current setup is 255 in the front and 275 in the back. Thanks peeps:thumb:
 

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Larger wheels will be heavier than smaller wheels. More weight will translate into longer stop distance, and longer acceleration times. MPG will decrease. Rotational mass can have quite an affect on performance. This is true for larger brakes as well.
 

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I forgot to mention unsprung weight.
On the other hand, I do like large, deep dish, wheels on the right car. Unfortunately, it' a balance between what you want, and what else you want. And something about doing what you want. /grin
 

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18 will allow more sidewall assuming the same tire height as a 19, the added sidewall will absorb the hit better and lead to better traction vs a low profile 19 or 20.
 

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Difference in rim size and putting down power, yes, but as already mentioned you want more sidewall (smaller rim) to absorb the initial hit. You want to go wider, not taller. Look at the drag strip, 15" wheel is common. If you like the larger wheel, lower profile look, you may be able to go taller and wider with similar results but unless you're running something skinny on the rear, I doubt you'll do much better traction wise.
 

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Difference in rim size and putting down power, yes, but as already mentioned you want more sidewall (smaller rim) to absorb the initial hit. You want to go wider, not taller. Look at the drag strip, 15" wheel is common. If you like the larger wheel, lower profile look, you may be able to go taller and wider with similar results but unless you're running something skinny on the rear, I doubt you'll do much better traction wise.
Confusing post is confusing.

OP, 18s or 19s will be your best bet. If you're worred about performance don't get heavy 20s. Whatever wheel you get, make sure it's a lighter one. Forgestar and HRE come to mind. Now is also a good chance to get wider tires. I would shop around and pick a tire, and then size your wheels to match whatever size tire you want. Make sure there's a few tire choices in that size, just in case.
 

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Difference in rim size and putting down power, yes, but as already mentioned you want more tire sidewall (so go with a smaller wheel aka rim) to absorb the initial hit (meaning when the wheel is stationary and force is applied, it rotates enough to spin the tire on the road. If there is more sidewall of the tire, some of that force is absorbed by the sidewall and allows the tire to plant a little better. I say little because you're talking 18-19-20" which depending on your current setup, you may fit a taller tire and negate any difference in sidewall size, or at least the benefit from such a small difference. You want to go with a wider tire (255 to a 275 or 275 to a 295 etc), not taller (18" to 19") for traction. If you look at the drag strip where cars are launching hard and want max traction, 15" wheel is common. If you like the larger wheel, lower profile look, you may be able to go with a taller and wider tire (see sidewall explanation above) and have similar results as you have now but unless you're running something skinny on the rear (like a 255), I doubt you'll do much better traction wise going to a 19" or 20" setup from the 18".
Is that a little clearer? Now the suspension and tire compound/type can ensue. Shoulda stuck with Voltwings reply:banghead:
 

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You want to go with a wider tire (255 to a 275 or 275 to a 295 etc), not taller (18" to 19") for traction. If you look at the drag strip where cars are launching hard and want max traction, 15" wheel is common. If you like the larger wheel, lower profile look, you may be able to go with a taller and wider tire (see sidewall explanation above) and have similar results as you have now but unless you're running something skinny on the rear (like a 255), I doubt you'll do much better traction wise going to a 19" or 20" setup from the 18".
Is that a little clearer? Now the suspension and tire compound/type can ensue. Shoulda stuck with Voltwings reply:banghead:
You're getting there. But you're still kinda confusing in that first sentence.
A taller tire will increase grip as well as a wider one. Taller actually helps more than width believe it or not, and that is a function of both sidewall and contact patch. Depending on the type of tire and compound, a 27" tire on a 19" wheel would likely grip better than a 26" tall tire on an 18" wheel. Even though they have similar sidewalls, the contact patch on the 19" setup is larger.
Of course, a 15" setup is gonna be worlds better for hooking a launch, but not everyone wants to daily a 15" with slicks setup.
 

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You're getting there. But you're still kinda confusing in that first sentence.
A taller tire will increase grip as well as a wider one. Taller actually helps more than width believe it or not, and that is a function of both sidewall and contact patch. Depending on the type of tire and compound, a 27" tire on a 19" wheel would likely grip better than a 26" tall tire on an 18" wheel. Even though they have similar sidewalls, the contact patch on the 19" setup is larger.
Of course, a 15" setup is gonna be worlds better for hooking a launch, but not everyone wants to daily a 15" with slicks setup.
All else equal, explain how that works?
 

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Contact patch is a function of tire diameter and tire width, as well as pressure, weight, and a bunch of other stuff
And on the op's car, pressure, weight and a bunch of other stuff is the same. We're only talking about changing tire size. I'd argue that given the wheel well is only so big, the overall diameter of the tire has to stay within a confined size. Increase the wheel and the sidewall becomes less. Sure you may get a larger contact patch going with a wider tire, but op can get a wider tire in 18" and keep a larger sidewall vs a 19" or 20".

Yes, my first sentence previously should have stated taller wheel, not taller tire.
 

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Yes, and assuming the same tire (255 for example), a 255/xx/18 will have more contact patch than a 255/xx/19 because of the added sidewall. If you take a 27" tire on a 19" rim and a 26" tire on an 18" rim, i have a hard time understanding how the 19 will just have more contact patch. In my mind it wont, you're confusing a taller overall diameter with a taller tire (ie: more sidewall).
 

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Yes, and assuming the same tire (255 for example), a 255/xx/18 will have more contact patch than a 255/xx/19 because of the added sidewall. If you take a 27" tire on a 19" rim and a 26" tire on an 18" rim, i have a hard time understanding how the 19 will just have more contact patch. In my mind it wont, you're confusing a taller overall diameter with a taller tire (ie: more sidewall).
I'm not confusing anything. A 27" tire has more contact patch than a 26" tire, regardless of sidewall or wheel size.

And yes, while you have a finite amount of space, you can easily fit a 28" tire in the rear. Possibly even bigger depending on suspension, tire width, wheel offset, etc

Last i checked this only worked on a pc, but cool tool to play with
http://bndtechsource.ucoz.com/index/tire_data_calculator/0-20
 

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So dont take it personally, i dont take anything at face value and like to approach everything with a healthy dose of skepticism.

I went on Tire rack and found 3 identical tires except for the height. All Michelin Pilot Super Sports in 255.

255/45/19
Tire height: 28.1"
Tread width: 9"
Michelin Pilot Super Sport

255/40/19
Tire height: 27.1"
Tread width: 9.1"
Michelin Pilot Super Sport

255/40/18
Tire height: 26.1"
Tread width: 8.5"
Michelin Pilot Super Sport

Still makes zero sense to me, but there it is i guess.
 

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So dont take it personally, i dont take anything at face value and like to approach everything with a healthy dose of skepticism.

I went on Tire rack and found 3 identical tires except for the height. All Michelin Pilot Super Sports in 255.

255/45/19
Tire height: 28.1"
Tread width: 9"
Michelin*Pilot Super Sport

255/40/19
Tire height: 27.1"
Tread width: 9.1"
Michelin*Pilot Super Sport

255/40/18
Tire height: 26.1"
Tread width: 8.5"
Michelin*Pilot Super Sport

Still makes zero sense to me, but there it is i guess.
You are only thinking one dimension. Width. A contact patch is two dimensions. Length and width. Tire width of course determines width, tire height and a bunch of other variables determine length. This is why lowering pressure helps, it lengthens the contact patch. Go ahead and play with the calculator i linked, it shows my logic pretty well
 

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That makes sense, but why the same 255 with the same sidewall is 1/2" narrower does not.
That's most likely due to certain tires being made for certain vehicles, for instance, especially with mpss, you'll see a few of the same size but with different specs. That's because BMW or Mercedes... or Ford... asked them to make the tire a certain way
 

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You are only thinking one dimension. Width. A contact patch is two dimensions. Length and width. Tire width of course determines width, tire height and a bunch of other variables determine length. This is why lowering pressure helps, it lengthens the contact patch. Go ahead and play with the calculator i linked, it shows my logic pretty well
I get the logic, but you're still missing the point that you can only fit a 28" tire (as you say) and that tire on a 18" rim or 20" rim will hook better on a 18" rim because it has the same contact patch due to the equal outside diameter of the tire, the width being the same but a larger sidewalls ability to take some of the initial hit.
 
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