Hi guys.
Looking at scoper's thread and a thread with hre p47 concaves has made me want different wheels ...
how is the ride affected with 20s?
I have sport pasm and the 19s that came on the car and I'm fine with the car in "soft" mode and I don't want to change the comfort levels too much.

 

then don't mount 20" wheels. It's hard to believe every inch makes such a huge difference but it does. Keep in mind your car's suspension was set up with 18" wheels (the smallest OEM wheel offered). Very typical. I agree, 19" isn't bad. At least with Michelin PS2s.

 

I had 19" HREs on my 996 that I just sold.
After a cracked rim & 2 flat tires in 48 hours I swore off aftermarket non OEM size wheels forever. It's such a headache to be stranded for a few hours & waiting for local tire shop to get the tire you need to get on the road again.

Going down only 1 inch to 18s with a bigger sidewall made a really noticeable difference in ride quality and comfort ...also my confidence increased a little while cornering at higher speeds.

Bigger wheels/tires sure look better but I prefer performance over looks any day of the week now. Especially if your 911 is a daily driver.

 

I thought all c4s cars had 19" as standard not 18"?

 

20's look Ghetto on our cars, and yes the difference is noticeable from 19's

 

Different experience here...my car came with 20" dealer-installed Modulares, and there was no noticeable difference in noise or ride quality when I went down to the 19" OEM size after a few thousand miles. I can't say that I would go back to 20s, but the car drove perfectly fine with them on Dallas roads that are worse than what you'd find in some 3rd world countries.

 

I don't think that 20's impact ride quality very much at all. One will undoubtedly get into discussions about increased unsprung weight and how it affects performance, etc. I really feel you have to assess how the car will be used most frequently (i.e., are you going to track it more, or DD on highways, etc.) With 20's the biggest thing I constantly worry about is potholes - last thing I want to do is ding one of the wheels beyond repair. Thankfully, while Portland has pretty rough roads (resulting in lots of road noise), we are relatively free of potholes, at least where I drive. Car has been fine on spirited drives on the backroads, but on the other hand, if I ever do any DE's I'm going to put back on my stock 18" wheels for that event.

Hope that helped a bit.
Ron

 

I don't have a Porsche but I've been riding on 20's for many years and I've never cracked a wheel. Only flats I had were the result of running over something like a screw or nail.
My wife rides on 19's and she is brutal on wheels and tires. No flats or broken wheels from her either.

The difference in ride from 19 to 20's is not an issue. It's so miniscule you wouldn't know the difference if you are not a pro.

 

+1, those who say it makes a huge difference don't really know what they are talking about. I had 19"s with Toyo's and they ride harsh compared to 20"s with PS2's which feels soft. 20"s isn't bad at all with the right tires, if that is too hard for some then it's time to get a Cadillac.

 

You can get similar ride characteristics between a 19" and 20" wheel if you change to a softer tire when you go up to in size. There are several things that will affect the answer to this question. If you maintain a similar sidewall height, then you can keep similar ride comfort given the same tire. If you go with a shorter sidewall, but change to a tire with softer ride characteristics when you go larger, again you can maintain ride comfort to some degree. There is no concrete answer to this question except that if you go up in rim size, but run the same tires with a similar overall height (and hence shorter sidewalls), then the ride will get harsher.

You of course have to be careful with maintaining the same sidewall height because the taller tire may not clear in your wheel well anymore and may rub in any number of places, especially when turning. On a 997 you will definitely have to run a very short sidewall with a 20" wheel to have clearance in the wheel wells, so your ride will definitely get harsher and there is no way to maintain ride comfort at what you have now.

Irregardless of all of that, a 20" wheel doesn't look great on a 997 anyway so I'd just stick with a 19". That's not just personal preference but the overwhelming popular opinion. For the record, my street wheels on my 996 are 19" and I think they look much better than the stock 18", but 20" wheels just look silly. Then there's all the performance issues, the much greater expense of the tires, the difficulties in finding ones that fit, rubbing, yadda yadda yadda...

What did the 19" wheels have to do with getting 2 flat tires? And what about the cracked rim? A lot of times something that will crack a 19" rim will crack an 18" rim just as easily since the tire grows in height as you go bigger and you end up with a similar sidewall height (and hence similar protection characteristics).

You're invalidating your own argument. You're saying that the tires make a difference and a larger rim will ride harsher unless you pair it with a softer tire. So obviously it does make a difference in ride quality to go larger.