Would Love Your Opinion
#17
You'll find many opinions about 18" vs. 19" wheels. You absolutely can autocross your car with 19" wheels. Many people do it. There are several things to consider.
Advantages of the 19" wheel:
- Looks very good. There are many aftermarket choices that look great with a Porsche 996.
- Some aftermarket wheels weigh less than OEM 18" wheels, even with the heavier tire. Less weight is good if you can find a light weight wheel that you like.
Disadvantages of the 19" wheel:
- Not all manufacturers have the same quality standards. Autocross puts more stress on the wheels/tires than daily driving, so make sure you choose a reputable company. I personally wouldn't buy a wheel that's made in China.
- Larger wheels mean less rubber sidewall. With less rubber between the wheel and the road, the chance of damaging your expensive new wheels is increased.
- Many people report a harsh ride with a 19" wheel vs. an 18" wheel. This is a personal preference issue and may not matter to you.
- 19" tires are generally more expensive than 18" tires, although the difference is relatively small. The reason I bring it up is that you'll go through tires pretty fast if you regularly autocross your car.
- Now for the controversial point: the 996 wasn't designed for 19" wheels/tires. You may say: "So what, the rolling diameter of the 19" wheel/tire combination is the same as the OEM 18" combination". This may be true, but that's not the issue. The issue is gyroscopic stabilization force. This force is created by the rotation of the wheel and tire. It's the same force that makes a bicycle easier to balance when it's moving vs. standing still.
In a 19" wheel/tire combination vs. an 18" wheel/tire combination, there is less rubber and more metal rotating far from the axis of rotation. Even though the 19" combo might weigh less overall, there is more weight at the edges, far from the axis of rotation. This means that the 19" wheels produce a greater gyroscopic stabilization force. You might ask: "So what"? The issue is that the increased gyroscopic stabilization force is transmitted exponentially to the steering, suspension and brakes of your 996. The next question is: "Does this really matter"? In normal street driving, it probably doesn't matter at all. In the extremes of a track use or autocross use, it may become a factor. Porsche never tested the 996 with 19" wheels, so we simply don't know. It might be okay, it might not. The 997 is offered with 19" wheels, and the suspension components were modified to accept the greater loads.
I'm not trying to sway you from 19" wheels. If you want them, then you should buy them. I'm just trying to provide a little information to help with your original question.
I personally would stick with 18" wheels, especially if I were going to track or autocross my car. Again - many other people use 19" wheels and you certainly can if that's what you like.
Advantages of the 19" wheel:
- Looks very good. There are many aftermarket choices that look great with a Porsche 996.
- Some aftermarket wheels weigh less than OEM 18" wheels, even with the heavier tire. Less weight is good if you can find a light weight wheel that you like.
Disadvantages of the 19" wheel:
- Not all manufacturers have the same quality standards. Autocross puts more stress on the wheels/tires than daily driving, so make sure you choose a reputable company. I personally wouldn't buy a wheel that's made in China.
- Larger wheels mean less rubber sidewall. With less rubber between the wheel and the road, the chance of damaging your expensive new wheels is increased.
- Many people report a harsh ride with a 19" wheel vs. an 18" wheel. This is a personal preference issue and may not matter to you.
- 19" tires are generally more expensive than 18" tires, although the difference is relatively small. The reason I bring it up is that you'll go through tires pretty fast if you regularly autocross your car.
- Now for the controversial point: the 996 wasn't designed for 19" wheels/tires. You may say: "So what, the rolling diameter of the 19" wheel/tire combination is the same as the OEM 18" combination". This may be true, but that's not the issue. The issue is gyroscopic stabilization force. This force is created by the rotation of the wheel and tire. It's the same force that makes a bicycle easier to balance when it's moving vs. standing still.
In a 19" wheel/tire combination vs. an 18" wheel/tire combination, there is less rubber and more metal rotating far from the axis of rotation. Even though the 19" combo might weigh less overall, there is more weight at the edges, far from the axis of rotation. This means that the 19" wheels produce a greater gyroscopic stabilization force. You might ask: "So what"? The issue is that the increased gyroscopic stabilization force is transmitted exponentially to the steering, suspension and brakes of your 996. The next question is: "Does this really matter"? In normal street driving, it probably doesn't matter at all. In the extremes of a track use or autocross use, it may become a factor. Porsche never tested the 996 with 19" wheels, so we simply don't know. It might be okay, it might not. The 997 is offered with 19" wheels, and the suspension components were modified to accept the greater loads.
I'm not trying to sway you from 19" wheels. If you want them, then you should buy them. I'm just trying to provide a little information to help with your original question.
I personally would stick with 18" wheels, especially if I were going to track or autocross my car. Again - many other people use 19" wheels and you certainly can if that's what you like.
My advice is also to stay with 18" wheels on the 996. When the engine failed in my 2000 996 three years ago, I got a replacement engine from Porsche and decided to get new wheels too! I got HRE 19" without doing enough research and found first and foremost that they slowed my car down noticeably (specifically in acceleration). They also rubbed all over the place (on bumbs, when the steering was turned all the way etc. etc.even after rolling my fenders!) Finally, I went back to 18" wheels with spacers (sold my 19"HREs at a big loss).
Final note I want to make is that my 2000 996 came standard with 17" wheels with 18" wheels from the factory as options. I do not think it is possible to match the rolling radius of the standard 17" wheels with 19" wheels even with super low profile tires. But you can match the rolling radius of the 17s with 18s with the right tires.
I like the OZ wheels on post #2!
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Feelgood MD
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03-24-2016 09:35 AM