Gee, I thought this forum was intended to be informative and supportive for Porsche owners and admirers.

 

Just trying to help my buddy RonCt from a mental breakdown and getting hives!

 

Exactly, which is why a bunch of us are trying to give the reasons why Porsche says not to put 20s on their cars. I remember several forumites jumping into 20s early on and then put them on the market because the ride was too harsh. The question was about 20s and a bunch of us gave fair warning. If the OP still wants to get them, all power to him - just that now he is informed of the downside risks.

 

RonCT, not only do the 20's make the ride harsh (in a bad harsh way) they make the car more uncontrollable over bumpy harsh pavement. A stiff riding correctly done suspension system on a Porsche is one this but the extra heavy 20's and the stock suspension trying to keep up with them and control them is another issue.

I hope this helps.

 

I've been driving on my 20s for 2 years now and love them. Yes there is a slightly harsher feel that was more noticible within the first month of changing out my 19s. Now, I hardly remember the difference, but that could be because of the roads in south east Florida.

 

Other than posters' opinions, does anyone here have any significant independent research that shows differences in performance vs wheel size for the same tire brand?

I'd expect that if you put 1" wider tires on the car, that additional tread would offer additional steady-state traction. I get the unsprung weight/rotational inertia arguments. What I want to know is can anyone prove it via a direct comparison from an independent (i.e. NOT a "butt dyno") source?

Thanks!

Kurt