Hey guys, I have 2006 C2S , I want to put on some 20"s what is the biggest rear wheel I can put on. I have seen 11.5" is it possible to go bigger? I want to get the HRE 847r wheels any suggestions?

 

Oh and does anyone know if we get a deal on HRE wheels for a group buy!

 

I have seen 10.5 front and 12.5 rear, Anyone have experience with those?

 

I think you may not be getting any reaction because 20s on a Porsche just don't look or work well - really shows off the "small" size of the rotors. In the 18 and 19" wheels, the rotors look correct. Change that to a 20" wheel and the rotors look downright puny.

You may end up causing damage to the suspension system as it was designed by Porsche to handle 18s and 19s. I remember reading a magazine article about this - where suspension geometry and bits and pieces for the 997 had to be upgraded just to handle 19s (up from the 18s the engineers wanted vs. 19s the marketing department wanted). If you recall years ago, there were problems when people were putting 19s on a car designed for 18s, problems with 18s on a car designed for 17s, etc.

Also, why punish yourself every day with a harsh ride due to the reduced sidewall? Porsche went so far as to have OEM tire companies make "different" Porsche N-rated tires just to get more sidewall, especially in the back. That's why 997 rear tire diameter is about 26.5, which is up 1" from normal.

As for widths, The biggest Porsche puts on the narrowbody is 9" front and 12" rear (ie GT3).

 

If you want to keep the handling performance of your Porsche stick with 18" or 19". For the street if you just want some really good looking wheels stay with 8.5x19 front and 11 or 11.5x19 rear. The HRE P40's look awesome by the way.

Also be careful of overall wheel/tire weight. The shock and springs have been designed to work well with in a certain parameter of unsprung weight.

 

20's will slow you down too.

 

Got 20's. You can definitely tell a difference in performance characteristics however, the 19's look downright too small on the car. Looks very unproportioned. I would go 20's and I would love it if they made the HRE C21 in 20's because with that step lip, the rims look smaller then they are.

 

What amazes me is that for decades 17s were "big" and 18s were unusually large. Now there are those that think 19s look downright small? Take a look at these 19s over huge PCCB rotors and calipers. A 20" wheel would make those brakes look tiny. To each his own...

 

Wow, I did not know that that was what the 'N' spec meant. I think I just purchased 'standard' PS2's when I replaced the Pirelli's (yuck) a year ago. Wish I had known that. Pilot error.
My two cents on the 20" wheels is that while I'm not a fan of the choice, look or weight, there is a reasonable correlation between those who choose the wheels and more modest driving habits. Likely don't track or street race. If they did, they wouldn't sacrifice performance for looks. And since they don't, the risk to the suspension due to weight and marginal geometry differences is modest.
To the OP, enjoy the mod. Just heed the advice that it stresses the car significantly and also forces a higher level of attention when you're driving as they are more apt to follow ruts and grooves in the road. To say nothing of vibrating your eyeballs making it hard to text while you're on the road. 'Course, you wouldn't ever do that anyway, right??

 

To me 20's look funny with all wheel and no tire side wall and they make the rotors look small plus if you car is not lowered you will see a lot of wheel well area.

However just get what you want.

 

Thats great all the feed back. It comes down to looks vs performance. I don't really plan on tracking my car and it is really just a weekend driver.I have red calipers and think have nice big 20's would be easy to clean and look great with the red. I think I want to run 20" x Front and 20"x 12.5 on rear. I will still have my stock 19" just incase I need to track.

 

I don't think you are hearing us... 20's have nothing to do with track driving. For the track you'd be going to 18s, which are the best design for these cars street or track. 20s are not good street wheels, can cause damage to suspension parts, are heavier, are going to give you a terribly rough ride, etc.

 

I think he is hearing you loud and clear. He does not want the 19's. It is a matter of personal preference and I have never heard of 20's causing any kind of suspension damage unless you are just using rocks for rims. Regardless of whether or not the rims are 18's,19's,20's, a pothole will kill each and every single one of these rims especially if you are running a low profile tire.

The 20's are a bit heavier, but there is really no noticeable change in ride quality between 19's and 20's that make you go "WOW, I should of stayed with 19's." If you don't like 20's, that is ok. It is all a matter of personal preference but some of the reasons that you guys really put out is all relative and it can be said regarding each size 18' and up. NOT just 20's.

 

My misunderstanding. I thought he was saying in effect "I'm not tracking so the 20s should be fine" when the reality is they won't be fine - they will be a harsher ride, heavier, worse performing (rotational / unsprung weight issues), are more likely to be damaged, etc. For every 1" you go up, your likelihood of damage to the suspension and the wheels increases. Anyway - we're all just trying to help. As long as you understand all of the downsides...

 

Ron, give it up buddy! These guys just do not know or care. Let them get the freakin funny looking pimp 20's....