increasing wheel size

[cash05_mustang]

i have purchased a set of 16" waffle star GT wheels with tires already mounted on them. i am wondering how much of a difference it will make in my speedo to the actually speed i am going. the tires i have on now are 205/65, and the new ones will be 225/55.

[SpectorV]

there wont be a difference at all in the overall diameter of the tire (which is what effects your speedometer) if the 16 inch tires are the OEM mustang size, and going by your specs you gave they are. So you will not have any problem.

[cash05_mustang]

yes they are OEM 16" mustang size. and thank you for the news i was hoping to hear. thank you very much

[Dark02Pony]

are your stockers 15" ? if so going from a 205/65/15 to a 225/55/16 will be off less then an mph so you have 0 to worry about. In reality going 60mph your speedo will read 59.4 If right now you have 205-65-16 and go to a 225-55-16 your speedo will read 1.7mph to fast.

[cash05_mustang]

thanks dark pony
you are right i have 205/65/15 going up to the 225/55/16.

[Kiljosh]

so make sure you dont go 61.7 in a 60.

[SpectorV]

tread wear and non exact tire making processes are also going to throw off the speedo... lol you cant consider the numbers a constant due to every tire maker does it different... you would assume 245mm is 245mm on all tires but... many tires are more narror/wider than others with the same size spec... very odd.

[cash05_mustang]

so i got those wheels and tires and the new ones actually turned out to be smaller, how should that effect my speedometer?

[Dark02Pony]

you'll only read 0.6mph fast dont stress it.

[Cajun JungleBoy]

bump