I've never understood why someone would put 20s on a porsche, and that's coming from a guy with 22s on a cayenne.

 

The weight of a wheel has no effect on the quality of the ride. As has been stated, wheel diameters do affect the ride. Lower profile tires and sidewall construction of the tires affect the ride, nothing revelating. The weight of the wheel affects performance though minimal. Acceleration, braking and handling are affect by the weight. The unsprung weight equation states that the force necessary to rotate a mass ( the wheel ) is 3x's the weight of the mass. Hence if a wheel is 8 lbs. heavier then it will require an additional 24 lbs. to rotate this wheel and that's per corner. Also as someone stated about the PCCB that this is one of the advantage of these brakes. Hence the performance qualities the vehicle are enhanced.

 

Yes wheel weight affects ride quality! It is well understood by designers that ride quality is a function of the ratio of sprung weight to unsprung weight of a vehicle, unsprung weight including wheel/tire weights. However, going from 18's to 19's to 20's will likely have a more profound impact on ride quality than 10 lbs of wheel weight per corner. As stated above, lighter wheel/tires/brakes permit the suspension to be more responsive. . . it has less mass to damp.

LTW wheels improve dynamics of the car, braking, accel, turning, as already noted above. Don't expect dramatically better dynamics as measured in terms of braking distance, 1/4 times, *however* ltw wheel/tire combos can definitely be felt.

On my track car, I've compared back to back wheel/tire combos that have 45lbs of mass difference (all four). Huge difference in responsiveness of the car.

 

Thanks much. I wonder how he changed the firmness. You know?

 

So you all know, I have 19s that I use on the track. 20s look great to me. I use those to drive daily. Granted, like I said, the ride's rough. It's likely due to the combination of PSS and the 20s.

 

The OP is asking about 20's from a ride/quality/stiffness perspective not about "TRACK" performance which it seems some people tend to deviate back to.

The 20's and the 19's should have the same rolling diameter and the tire height should be very minimal. Weight should not be a factor in stiffness but more so in responsiveness. I do not understand the need for PASM when you have a progressive spring, adjustable height and dampening. You are defeating the reason for a COILOVER SYSTEM which is to dial in your car to the way you drive it and leave it alone. Hitting PASM on an already dialed in suspension defeats its purpose. You tighten up the ride that you worked to dial in.

I have had 20's on most of my cars for a long time now and waiting for a set of BLING 20's for my 997TT. I hate it when people try to tell me that my 20's is not trackable. NO kidding. Also two years ago you would say that about 19's and now it is very common. GT3(RS), GT2(997). As more and more R-compound tires become available in the 19's they will be more common as people can put them on their cars and drive it to the event and then drive it home.

+1 size will not kill your car. My turbo comes with 19's and I went with 20's. My M5 has 20's, my lexus has 20's and I can tell you that no one has ever complained about the stiffness of the coilovers because I set them for street and leave them that way. No PASM to make them STIFFER.

Blakt Out - try to adjust your dampening a little for the street and hit PASM for the track.

 

I totally agree with you ALPINE i just got 20 inch dpe s-15's on my 997 c4s and the handeling feels much better than with the stock 19's. it's prob. more rubber on the road from the 325 25 20 pzero's. I'm just about to lower this ride too with H & R springs. I dont know why most porsche guys want a soft ride like a merc. I say the harder the better, who wants to float around in pcar anyway...19's just don't fill out those wheel wells like a true 20 inch wheel...plus people just love the way it looks way better than any 19 or a fuddy dutty 18 inch wheel....

 

After having a really hard car, I disagree with you. I doubt seriously that how aggressively you drive validates an uncomfortable suspension. The cars are very capable from the factory. Just my 2 cents... which I get to give freely 'cause I started this thread.

Anyway, I track my car, and think I'm a decent driver. Have my SCCA license and all that. I want to soften it up a smidge because it's so uncomfortable on bumpy NC roads. I'll do like was previously mentioned and work on softening up my Bilstiens and the ride height.

Just wondered if, ceterus parabus (all things equal) if a lighter wheel would feel softer than a heavier wheel. That's the point of the thread.

 

Read the new Road & Track -- there's a well done summary of why anything over 18" is a waste due to diminishing returns. It's all about sidewall and at 18" the ratio is just right, which explains why everything written says that the 18s on a 997 are superior in every way to the 19s. Excellence has written about this several times.

Want the best ride? Get some lightweight 18" BBS and some PS2s in 235/295 and use the pressures suggested (so many people over-inflate). In the middle might be 19" oems. Worse would be heavy 20".

 

Road and Track who are they?

 

Have to keep up on the rest of the auto industry you know Excellence only covers Porsches and I've got an Audi winter driver, Volvo wagon for my wife, and a VW Jetta for the kids...

 

Ok there are so many variables, but of course unsprung weight and a smaller diameter wheel can effect ride comfort and quality for the better!

 

Yeah who's road and track, lol alpine your right again, i think we should take a poll of how many 6speeders track their cars? i mean sure all track guyz will vouch that 18's are the best FOR TRACKING... but why not 17's or 12 fuchs I mean all I can say is that Im happier with the new handles and looks of my Blingy 20's what more could you want...

 

If you think 20s improve the handling you really have no clue what your talking about. You can like the looks of 20s, nothing wrong with that, but they do make the handling worse. I just think 20s take away from it being a true sports car and make it more of your typical flashy ride you see infront of all the clubs.

 

I really like how this subject always brings out the best in people...yeah like a guy with 20's cant pass or out corner the guy with 18's, lol....