Dennis,

Overall tire diameter is the key with the way a tire fits on the car. You'de be an f'ing idiot if you run a 315/45/19 on your car because it will be to tall. running a 315/25/19 is the same diameter as a "stock recommended tire"

The car doesnt give a rats *** of how big the rim is or how short the sidewall is. That is proven data.. numbers dont lie.

 

The reason that I made my first response in this thread was because I thought the original poster may be new to the world of the 996. The fact is, the 996 wasn't designed or tested with 19" wheels. It was designed and tested with 18" wheels as the maximum. The 19" wheel and tire combination can be very close to the 18" in terms of total rolling diameter, but there are other trade-offs.

First of all, 19" wheels are often heavier than 18" wheels. This extra weight puts additional loads through the suspension during hard cornering in particular. Additionally, larger diameter wheels have smaller sidewalls to try to keep the diameter close to the OEM recommendations. This results in greater impact forces being transmitted to the suspension components. Finally, the 18" wheel and tire combination is not only optimized to prevent you from damaging your vehicle, it is optimized for performance. Going bigger doesn't necessarily improve performance as many people think, it can actually decrease performance.

If you have legitimate data that show that the 19" wheel is acceptable for the 996 and won't cause long-term damage to the differentials or other components, then by all means please enlighten us. Perhaps you have data that show that the additional weight of the larger rim that is further from the axis of rotation than the OEM recommended sizes won't damage the suspension or drivetrain. If you don't, then all you're really offering is anecdotal evidence that this combination is acceptable. That's fine for some people - it all depends on what you want out of your car.

The original poster was asking for recommendations on tire sizes for 19" wheels. The question he has to consider is this: Do I trust the recommendations of a few people who I've never met, or do I trust the recommendations of the manufacturer of my high-performance vehicle? I know which one I trust...

I don't have any issue at all with people who decide to put 19" or bigger wheels on their 996. It's their vehicle, and it's their personal preference that's important. What I do have an issue with is making a decision without understanding all the facts. Let the OP read about the facts and make up his own mind! If you really think it's stupid to consider all the facts when you make a decision, then there's really no point in continuing this discussion. It obviously won't go anywhere.

 

Here's a nice one from the Cayenne forum. I'm sure this Cayenne "doesn't give a rat's ***" about these wheels...

 

again dennis

You brought up another point that is not true. Weight. Did you know that a good set of 19s can actually weigh LESS that factory 18s?? Hmm more research buddy will keep guys like me at bay.

did you also know that Porsche offers a 19 inch wheel combo?

Now you will probably come back with something like .. "We are talking about 996s here.. not 997s" Well... research transmission gearing and transaxle ratios and get back to me. If you find a difference between a 996 and 997 that will have anything to do with telling a member that running a larger wheel diameter is not recommended, Let us know.

I'll continue for another round if you'd like....

 

Sergio,

I don't want to argue. I put the Cayenne photo in for a little comic relief.

If you read my post, you'll notice that I say 19" wheels are often heavier than 18" wheels. I didn't say that all 19" wheels are heavier than all 18" wheels. So, what I said is true.

Did you know that Porsche doesn't offer a 19-inch wheel combo for the 996?

Look - I like 19" wheels. I think they look great on the 996. I have no reason to believe that this combination will have problems on the 996, especially since it is offered on the 997.

My point is simple. If you look at my original post in this thread, it reads as follows:

"19" wheels/tires aren't recommended by Porsche for the C4S, so it's hard to say what might happen to your differentials."

There are two key parts to this response:

1. 19" wheels/tires aren't recommended by Porsche for the C4S - this is true
2. so it's hard to say what might happen to your differentials - this is true

I didn't say something bad would happen. We don't know that because Porsche didn't test 19" wheels. However, we also don't know that it won't cause long-term damage. It probably won't, but we don't really know. That's all I was really trying to say here. I personally don't want to recommend something based on observations as opposed to testing by the manufacturer.

People come to forums like this for information. I'm just trying to provide information here, not argue about whether I like 19" wheels or not. There's nothing stupid about the truth.

 

lets not argue on here.. i dont want to feel too special <3

 

I agree. I'm looking forward to seeing a photo of your car with the new wheels.