RonCT

19s have a performance boost over 20s and 18s have a performance boost over 19s That's why all of us trackers us 18s on our 997 cars (C2, C2S, GT3, etc.). I tried Volk TE37 in both 19 and 18 and will stick with the 18s.

I do wish Porsche gave everyone the 18s as standard - I would have stuck with 18s on my C2S for the street and saved a few $.

sjfehr

I *think* the style came about because all the supercars have these giant wheels with rubber-band tires to clear the massive brakes but need a low profile for aerodynamic reasons, and people just subconsciously associate big wheels now with high performance. Was originally a performance tradeoff, though; the wheels/tires themselves were less desirable, but necessary to fit the brakes. Still holds true. Personally, I think they look better with a little sidewall. They look especially silly when you can see how small the rotor really is.

Now, on the other hand, I'm at a complete loss to come up with any plausible explanation for this:

rpalomo

i think ill stick to 19's and comprimise slight performance- i believe with good performance tire it should be fine since there seems to be enough room for a good amount of rubber....

back to my other question though- has anyone lowered there car with 18's or 19's. I have a C4 and was wondering what tire size i should be getting if i do get 19's. should i go with a 295 rear or 305...i see some people talking about getting 305 rears...

RonCT

The difference between 295 and 305 is psychological for street driving. On the track a 305 gives you a tiny big more contact patch, but of course unless you change the front you will create a little more understeer. I've run 295 and 305 on the track and the difference is marginal, so on the street it's irrelevant.

For my street use, I stick with the 235/295 that came on my C2S.

Take a look around, you might find a nice set of OEM 19s with TPMS and 235/295s on them for in the $2k range (I've gotten some that way). This forum's Classifieds / For Sale areas (you'd have to become a full member to access them) typically has some for sale, there's eBay, PCA website, etc.

brendo

besides saving a few bucks on tires, why do people prefer 18's over 19's? if the car was designed with 19's, i don't see the advantage on going down.

the nominal weight savings would be accomlished with a high end wheel at either size.

sjfehr

If that's the case, you'd see even more weight savings with an equally advanced 18" wheel. The wheel/tire combo is simply lighter with less metal and more pneumatic tire. It's only a small difference, but a difference nonetheless. It's a performance difference disproportionate to the weight reduction, as it's not only unsprung mass, but rotating unsprung mass, and at the end of the lever arm, to boot. And it's an easy one to gain, too- you actually save money doing it.

Aside from that, you're less prone to damage the rim on potholes, but the weight savings is the big one.

brendo

what about the dynamics of the original design having been paired with 19" wheels? it would seem to me that porsche took the weight into account

LagunaDallas

I saw your post and thought "no kidding" and then ironically saw you're from Dallas. After all of the rains and a few snow days this winter, it'd be hard to argue that our roads are in better shape than those in most third-world countries. I saw a pothole today that I swear was almost a foot deep.

rpalomo

From CA and roads arent bad at all....might encounter a few potholes here and there but orange county seems to fix them right away

RonCT

In order to find the full answer you have to really dig into old posts (of mine) and you'll find that the 997 is not designed around the 19" format, rather the 18, which is why the C2 and C2S come with 18, why 18 is the snow wheel / tire size for all 997 cars, etc. You'll also find that marketing wanted to offer 19s for these cars, but engineering pushed back... and lost. So, they had to adjust the design of the suspension / steering components to be able to work with 19s as well as 18s. I've also posted in the past about a Porsche race car driver in Japan that was one of the first to drive both the C2 and C2S back-to-back on a race course. Both equally set up, both wearing PS2 tires if I remember correctly. And during the drive and after he went on and on about how Porsche should have stuck with 18s for the C2S, how the 18s react better to irregularities in the track, etc. That little bit more sidewall makes all the difference. You still get crisp turn-in and overall steering response but you also get better compliance.

LagunaDallas

Agreed...I grew up in Orange County and spend summers there, and the road quality is incredible compared to most other parts of the country. My $.02 is that you go with 19s. I'm looking forward to my 20 > 19 "downgrade" soon! I personally don't think the 18s look big enough for the car. If given a choice in OEM wheels, I think the 19" Carrera Classics are clean, simple, and perfect for the car.

dasams

Resist the bling. You'll thank me later. dave

alexb76

To OP, PLEASE SEARCH, every single question you had has been answered MANY TIMES BEFORE. Also, some of your questions are just due to being super lazy! Only if you checked Porsche website car builder you can understand very easily what are the OEM wheel sizes and that 18 actually fits!

If you come here and ask EDUCATED question, you get a lot farther... while I see the usual suspects have been more than helpful today!

rpalomo

What did you do? click on this thread just to say your piece? Talk about too much time in your hands. Maybe the lazy part is a wrong assumption and time is an issue since I want to move rather quickly on this but whatever it is, if u have the time to answer in such a way maybe you can answer the question instead.
Starting the thread is still a form of research. it is a way of doing a more thorough research. Ofcourse i am still running other searches but in addition, this thread has been started incase I miss anything. Hope that is simple enough for you.

brendo

good info - i didn't see that level of detail prior. tx