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ORIGINAL: Birdieman4
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WTF???
Who would keep the same aspect ratio when plus sizing?
That is just silly (and not what you said ) and it will also cause your speedometer
to be off, in some vehicles can cause your shift points and transmission fluid pressures to change
Like I said, any change in tire diameter will have an effect, wheel size don't have a thing to do with it...
How are you going to aruge with PROFESSIONAL DRAG RACER? He knows what he's talking about and it makes perfect sense.
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I'm comparing apples to apples in tire charateristics. That's all. And we're not arguing here, we're discussing.
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Yup
No arguement here, I just feel thet it's common knowledge that when plus sizing you must adjust your aspect ratio to compensate for the increase in wheel diameter.
Like I said, not doing so can have greater consequences then just a change in effective gear ratio because the average person will not feel the difference going to a 1" taller tire..
It is used more in the 4x4 world where people change the tire diameter buy a lot more than an inch.
But since you brought it up.....
Lets use a stock mustang 245/45/17 and say that someone decides to use a 245/45/18
OldTireDiameter = 25.68 inch
NewTireDiameter = 26.68 inch
GearRatio = 4.10
New Tires
effective gear ratio = 3.9463268365817
and if you had 4.10's in a 01.5 - 04 Mustang with the 3650 with 25.68" tall tires
at 70 MPH in 5th gear, your motor is turning at 2,329.1 RPM
and if you had 4.10's in a 01.5 - 04 Mustang with the 3650 with 26.68" tall tires
at 70 MPH in 5th gear, your motor is turning at 2,241.8 RPM
only a difference of 87 RPMs
Heck if you lose 1/4" of tread over the life of your tire, that is 1/2" off of the tire diameter...Do you feel that? You're not going to feel double that either
No one will notice [&:]