Bigger Rear Tires
01-02-2008, 01:55 PM
#1
2nd Gear Member
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Bigger Rear Tires
The dealer wouldnt let me put on bigger tires in the back, they said it would make the ABS go crazy...(front wheels and rear wheels wouldnt spin the same speed)...They had to be the exact same tires on the front and back or they wouldnt mount and install for me...
That true?
That true?
01-02-2008, 02:11 PM
#3
6th Gear Member
Join Date: Feb 2007
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RE: Bigger Rear Tires
Not 'no', but not entirely so either.
It's partly true in that during a relatively hard stop, shorter front tires will indicate to the ABS module that front wheel lockup is about to happen a little earlier than is actually happening, and the ABS could momentarily release the front brakes which would increase your stopping distance. It is possible that some ABS systems might throw a light and a code depending on how much different the diameters are, but I don't know if the Mustang's does.
The tires need only be of the same diameter (within 3% or so) to keep most ABS systems happy. Just point to the factory OE tire sizes on the Shelby GT500 - 255/45-18 up front and 285/40-18 on the rear.
Depending on the ABS logic, you may want to stay close to 27" outside diameter. In addition to comparing rates of wheel deceleration against each otherit's possible to write code that keeps track of wheel deceleration vs some arbitrary value that would be consistent with the tire revs per mile (OE tire sizes or at least tires with similar outside diameters).
It's partly true in that during a relatively hard stop, shorter front tires will indicate to the ABS module that front wheel lockup is about to happen a little earlier than is actually happening, and the ABS could momentarily release the front brakes which would increase your stopping distance. It is possible that some ABS systems might throw a light and a code depending on how much different the diameters are, but I don't know if the Mustang's does.
The tires need only be of the same diameter (within 3% or so) to keep most ABS systems happy. Just point to the factory OE tire sizes on the Shelby GT500 - 255/45-18 up front and 285/40-18 on the rear.
Depending on the ABS logic, you may want to stay close to 27" outside diameter. In addition to comparing rates of wheel deceleration against each otherit's possible to write code that keeps track of wheel deceleration vs some arbitrary value that would be consistent with the tire revs per mile (OE tire sizes or at least tires with similar outside diameters).
01-03-2008, 01:35 AM
#6
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RE: Bigger Rear Tires
See my sig - never had an issue with the ABS system.
To answer your question though, it is true - they will not mount those tires for you (because they said so). However, their reasoning is full of ****. Go somewhere else.
To answer your question though, it is true - they will not mount those tires for you (because they said so). However, their reasoning is full of ****. Go somewhere else.
01-03-2008, 02:13 AM
#7
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Join Date: Nov 2006
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Posts: 15,618
RE: Bigger Rear Tires
Take it anywhere other than a dealer and they will do it and I dont have any issues with my tire sizes either!
ORIGINAL: ratnacage
See my sig - never had an issue with the ABS system.
To answer your question though, it is true - they will not mount those tires for you (because they said so). However, their reasoning is full of ****. Go somewhere else.
See my sig - never had an issue with the ABS system.
To answer your question though, it is true - they will not mount those tires for you (because they said so). However, their reasoning is full of ****. Go somewhere else.
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