I'm currently 36/40 on same PS2 combo.

 

I think it is better to add sidewall.

 

It's amusing, reading through this thread answers are all over the place. Everyone has an opinion and that's OK. We me get more agreement on the origin of the universe.

Anyway, to the OP on your original question, a 5% increase in aspect ratio on a 19" tire is not enough to make much difference at all.

The things that contribute to road shock and increase it are tire sidewall, which you are aware of, tire casing stiffness, air pressure in the tire, suspension spring rates, compression and rebound dampening rates.

Staying with 19s, there is only so much you can do especially if running 996 AWD. Things will improve with 18s but maybe not as much as you may expect. This is especially true if your dampening and rebound settings on your shocks are a bit high.

If you had a very tall profile 60 or 70 series tire you may be able to play with air pressure for a soft ride but not with either 19" or 18" without severely hampering road manners. Remember you have a ton of weight hanging over the rear axle and it's the air in the tire, not the tire itself that supports that weight. Too little air will cause tire overheating, tramlining and other issues.

So that leaves spring rates and dampening settings. Here are the basics, stiff springs are best for smooth roads as are high dampening rates. The rougher the roads the more shock/spring travel is generally needed and softer springs. The spring rates and dampening forces should be matched for the type of driving you do and the road surfaces encountered.

The good thing about adjustable dampening, which you have is the ability to change settings for a variety of conditions. I'd start by softening up the compression dampening front and rear and look at the rebound as well. If you are not familiar with doing this enlist the services of a shop that is. It will most likely be a race shop that has expertise in suspension tuning.

I would advise switching to 18s also, as even if you get the suspension sorted I can't imagine being happy with the shorter 19 skins for anything other than looks.

 

A lot of good information here. What it boils down to is what works for me may not for you. Fine tuning your ride is something we each have to do based on a lot of factors. The ****ty roads in my area are one of my concerns. I happy where I'm at and I can change things with my set up when I feel like it.

 

Thanks for the replies everyone. I think I will start by adjusting the PSS10s since that is free.99. I believe I have them set pretty stiff at something like 7 & 9. Then I think I will try new tires. I like a meatier sidewall for looks anyways.

 

that's my usual psi pre rwd conversion. these psi recommendations came to me from track rats. i've flattened it in the rear just a tad since all the power is to the rwd so a little less "bounce" in back is better.

 

When I want maximum traction for acceleration my 295/35/18 squat and grip nicely at 35 PSI hot..
But normal street driving 40 cold is a great ride with pothole safety..

 

I believe that Porsche went 19" wheels on the 997 cars for aesthetics more than function. Market norm was 19" wheels. If they were superior handling wheels they would have also switch the cup cars to the 19s, but instead they stayed with 18s. Just my $.02

 

Probably true. 991 turbos come with 20" wheels!

 

I went with 225/40R19 in the front and 295/30R19 for the rear. Didn't feel any difference from the stock tires. No rubbing, perfect fit.

 

That 's a good amount of sidewall, but it should be a pretty big mismatch front to rear, no? Could damage the front diff. Are you RWD?

After my research it seems to me that adding sidewall by switching to 245/35/19 and 305/30/19 is the way to go

 

Sorry..it should've said 295/30. Gonna try to correct it above. I did a lot of research and decided the 315s and 305s were all about an inch taller than stock, so I took the stock 18" tire sizes and applied them to the 19" wheels which gave me the same amount of meat on the tires with a 1" increase in overall diameter. This way the ratios between front and back remain the same as stock.

 

Please forgive my ignorance. But I am trying learn. Just purchased a 2005 Turbo S Cab. Only has 17k miles. Love it so far.


Can someone tell me what the X-73 suspension is?


Thanks,
Mark

 

Welcome to the site, and here you go:

https://www.6speedonline.com/forums/...uspension.html

A search will yield many other posts on the topic as well.

 

Excellent. Thanks for the link.
Mark