NJCoastFlyFish

I really like the look of bigger tires in the back, but was wondering how putting bigger tires affects performance and MPG. I know it gives you less acceleration, but how much of an affect are we talkin? 1/10 of a second off in the quarter? Or is it much greater than that?

My deal is I am not in the position to make any big purchases on my stang right now, I am thinking CAI and a CHIP before the spring but some bigger tires in the rear now to give it a little more of a muscle look.

I will probably end up saving the beans and going new bigger wider rims/tires all around....

Also you think some bigger feet in the back would help in the snow? Would the trac lock help a lot in the snow? Lasts weeks rains got me thinking of buying a beater explorer, I was all over the place, but then again I got to learn to take my foot out of it....

05stangkc

Its Tire Diameter The Effects the Perfomance of a vehicle the most. The Stock P215/65/16 Is approx. 27.0 Inches around. A shorter tire will give Greater Multiplication of torque where a Taller Tire will Increase Top Speed and Decrease Acceleration. It is advisable to stay within .6 of the Original Diameter or a Speedo Recalibration will most likely be necessary. Of Course there are lots of other factors such as weight and tire Sidewall which will effect handling. BTW on a V6 An Axleback exhaust is the BIGGEST Bang for the Buck Performance wise.
Oh and a Set of New Car Take Off Bullits are a Great buy for a V6 Upgrade. Usually $600.00 to $700.00 for 4 Wheels and Tires are hard to Beat.

Gearhead

Great comments. I would also add that the Diameter of a 265/60/16 is:
(26.5mm) * (1/2.54 in/mm) * 60% * 2 + 16" = 28.5"
so we get:
30 MPH * (28.5"/27.0") = 32 MPH
60 MPH * (28.5"/27.0") = 63 MPH
70 MPH * (28.5"/27.0") = 64 MPH
etc, so be advised for speeding tickets. You will be going faster than your speedometer indicates.

scrming

I had a set of BFG on the back that exact size:

My BFGs

I had them on my stock rims... They look really good... but... off they line they made the car feel very doggy... You'll need to get a new set of rear gears if you want descent off the line preformance...

Also as other have mentioned your speedometer will be off a fair amount... I have an SCT X-Cal2 so that was not a problem...

ex-Galaxie500

My biggest concern was the speedometer when upgrading my tires, so I kept the stock diameter and just got wider tires

NJCoastFlyFish

Ex Galaxie-what tire did you go with, can you fit wider tires on the stock rims and how wide can you go?

Yeah the bullits are a great deal on ebay, I even saw black 18in cobra rims for around $800 with tires, not bad

How excatly is the speed calculated on the 05 v6? I figured there was something wired into the front tires not the rear because when I'm peeling out my speed remains the same. I plan on getting a SCT or something in the future anyway with a CAI, had a run in with a 350z last night on the parkway and realized I need MORE HORSEs hehe

05stangkc-I already took off the stock muffler and went with a GT takeoff from casco and i'm pretty satisfied for the money I spent for it can't really beat it! But your right, that stock one seemed pretty restrictive

ex-Galaxie500

I am going with 255/50/17 Bridgestone Potenza RE750's. I got a great deal on some '06 GT wheels on ebay so I will be switching out wheels and tires in order to get them wider. I do believe you can go wider with the stock rim but probably not enough to make any difference.

You might want to check out these links to help you decide

Tire Calculator

The Tire Rack Tech Center