StangEatsRice

Will it be off? How much? I am tuning the car in april for 4.10's with a sct but will i be able to set it up so the car knows there 275/40 in the rear and 245/45 in the front? I need the tires now.

dpstang98gt

it will not be off very much if its any at all

StangEatsRice

does the rear even have a speedo thing i think it may only be for the front? If thats the case would the car even realize the diff tire size in the rear.

72MachOne99GT

274/40's and 245/45's are both right around 26.6inches tall I belive..

You'll be fine as far as teh speedo is concerned. And even if you had a differnet size, im sure the programmer will allow for tire height changes if you were going to DD a 28" slick ;-)

brock_07

i think the speedo thing is in the tranny cause if it worked on the front wheels u wouldnt have to fix ur speedo with a gear change.

Black_GT_02

You won't notice any difference with 275's.

dougs97mustang

my 97 is off 10 mph but i dont know if it is for that reason, it says im going 70 when im realy going 60. It realy racks up the miles[:@]

Black_GT_02

You probably have gears...i'd say 3.73's

oxfordgt

The diameter of the 245/45 is 25.68in and the diameter of the 275/40 is 25.66 so when your speedo says your doing 65 you are atually doing 64.95. Dont worry about a recalibration

72MachOne99GT

25.6 26.6.. bagh, same thing.. lol

Even if it were different though, I'm certain SCT , and other tuners for that matter could take into account a tire change.