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Old 10-23-2012, 02:35 PM   #1
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wheel offset

Iíve noticed that all new cars, Porsche include, come from the factory with positive offset wheels. Now Iím dating myself here, but back in the 60ís and 70ís, if you wanted a car with an aggressive look to it, you always had a wheel with a deep dish, which came from a negative offset. Even the 930 turbo from the 70Ēs had a dish to the wheel (negative offset)

So, I was wondering why this is. I realize a lot of it is just taste and style, and styles change over time. But I was wondering if front wheel drive had anything to do with this style change. A negative offset requires a narrower axel on the car. With the advent of FWD cars, there was not much room up front to put the engine, breaks , etc. With a positive offset wheel, the designer could put the brakes (disk, caliper) within the wheel, without widening the track of the car. But for a negative offset wheel with a deep dish, the breaks will be outside the wheel, and you either need to make the axel narrower, or the track of the car wider.

So with the advent of FWD cars, designers were forced to go with a positive offset, and that became the norm, and what we like today. Or is there some other advantage to going with a zero or positive offset that Iím missing?
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Old 10-24-2012, 03:08 AM   #2
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Positive offset is used for better suspension geometry. It allows the ball joint(s) to be tucked inside the wheel for less SAI and lower scrub radius, among other benefits.
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Old 10-24-2012, 04:25 AM   #3
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Originally Posted by surf40 View Post
I’ve noticed that all new cars, Porsche include, come from the factory with positive offset wheels. Now I’m dating myself here, but back in the 60’s and 70’s, if you wanted a car with an aggressive look to it, you always had a wheel with a deep dish, which came from a negative offset. Even the 930 turbo from the 70”s had a dish to the wheel (negative offset)

So, I was wondering why this is. I realize a lot of it is just taste and style, and styles change over time. But I was wondering if front wheel drive had anything to do with this style change. A negative offset requires a narrower axel on the car. With the advent of FWD cars, there was not much room up front to put the engine, breaks , etc. With a positive offset wheel, the designer could put the brakes (disk, caliper) within the wheel, without widening the track of the car. But for a negative offset wheel with a deep dish, the breaks will be outside the wheel, and you either need to make the axel narrower, or the track of the car wider.

So with the advent of FWD cars, designers were forced to go with a positive offset, and that became the norm, and what we like today. Or is there some other advantage to going with a zero or positive offset that I’m missing?
The real difference between higher and lower offset wheels with regard to oem fitment, has more to do with the manufacturer taking a more conservative approach to style than that of function; particularly when it involves rear wheel drive vehicles. When it comes to "tuner" wheels, virtually every aftermarket company utilizes a lower offset design. This typically results in not only a more aggressive look, but there's a goal for increasing performance as well.
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Old 10-24-2012, 09:56 AM   #4
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Those older 911's usually have widened or stretched rear fenders that allow for wider wheels and negative offset.

Positive offset is better for handling and performance. Negative offset is just for looks. For me, a +25 offset is perfect, but the lowest offset wheel I can find for the Boxster is a +48. Otherwise, I would need to buy wheel spacers to get a smaller offset without rubbing.
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Old 10-24-2012, 02:06 PM   #5
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Originally Posted by ProjectM96 View Post
Those older 911's usually have widened or stretched rear fenders that allow for wider wheels and negative offset.

Positive offset is better for handling and performance. Negative offset is just for looks. For me, a +25 offset is perfect, but the lowest offset wheel I can find for the Boxster is a +48. Otherwise, I would need to buy wheel spacers to get a smaller offset without rubbing.
Whoa, +25 offset ! What fitment are you referring to ?
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