magistro

Please inform me of the correct inflation pressure for:
fnt P-Zero 225/40/18
rear P-Zero 285/30/18
Thank you.

<a href="http://boards.rennlist.com/upload/P2200046.jpg" target="_blank">http://boards.rennlist.com/upload/P2200046.jpg</a>

KC993

Magistro,

I have 18" Turbo Twist on my C-4.
Cold tires, Front 36psi, Rear 44psi.
BTW, great looking wheels... <img src="graemlins/jumper.gif" border="0" alt="[jumper]" />

Rocket

The rennlist achives recommend running pressures of 30/32 psi front and 34/36 psi rear cold, and for track work maintaining these pressures when hot. The figures mentioned in the manual for 18 inch wheels especially 44 rear seems excessive, and a spirited drive can send this pressure way over 50 psi which is alarming when, for example, the Bridgestone SO-2 states on the sidewall that the maximum inflation pressure is 51 psi.

I would imagine running 36/44 would be inclined to cause the car to oversteer more than the pressures recommended by this board. From my own experience running 32 front 36 rear works well on road from a comfort/ride point of view and the tyres wear evenly. These values for track work also maintain even tyre wear and the car handles well enough in my experience.

Rocket

dcpmark

[quote]Originally posted by Rocket:
<strong>From my own experience running 32 front 36 rear works well on road from a comfort/ride point of view and the tyres wear evenly.</strong><hr></blockquote>

It's been 12 years since I've been to the UK, but if the roads there are anything like they are in Los Angeles, you can kiss goodbye to your 18" rear wheels at that tire pressure. One good pothole and you will have a bent rim, even with stronger factory rims, IMHO.

bloke

Have to agree with dc. If you are in an area that has many large potholes then use higher pressure. For me i used 35-41 somewhere in between and i use the car for daily commute and road isnt so great.

It is handling vs bented rims. so choose your posion carefully.

Terry Adams

After repairing one (18" hollow spoke) rear wheel and replacing another rear due to pothole damage, I err on the side of a little higher: 34/40 cold, but not the 36/44 spec. If the collective R&D of Porsche and the tire mfrs says 36/44, I am not inclined to go as low as 32/34 on my area's pathetic pothole ridden roads.

Ben in Plano, TX

I run 34 front/36 rear in S-02's.

Ben

Mike W

After experimenting at different pressures I find 36/38 works as the best compromise. I am fortunate that florida roads are pretty good with few potholes. Mike W

tmobley

DC - I also live in SoCal and will be in 18s in the next couple of weeks. What have you found the optimal tire pressure to be given the local conditions - both road and whether?

dcpmark

[quote]Originally posted by tmobley:
<strong>DC - I also live in SoCal and will be in 18s in the next couple of weeks. What have you found the optimal tire pressure to be given the local conditions - both road and whether?</strong><hr></blockquote>

I just run 36/44, and I check 'em once a month. They are usually down to to 34/42 by then sincethe car is not my daily driver. I'm running Michelin Pilot Sports, and I have no problems with handling, comfort, mileage, or anything else. I also don't have to worry about bending rims. Then again, I don't race or track the car.....just some "sporty" freeway and steet driving from time to time.

tmobley

Thanks DC - My driving habits are similar, but for the fact that mine is my daily driver(about 80 miles a day - sometimes more). I will be running the Contis (not by choice)and I will let you know how it goes.

KC993

Thank you Mark, <img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />
I know I am not the only one running 36/44.
BTW, Ben in Plano, north bound 75 exit Plano Pky.
stay in service road and cross the rail road track and intersection; see if you want to run 36psi rear... <img src="graemlins/wave.gif" border="0" alt="[byebye]" /> <img src="graemlins/jumper.gif" border="0" alt="[jumper]" />

Kevin Reilly

Ben in Plano, TX

KC993,

Good one - that's on my way to work every day!

I sometimes cross those tracks at a pretty good clip (getting around the suburbans and F150's so I can see where I'm going <img src="graemlins/burnout.gif" border="0" alt="[burnout]" /> ) and don't really have much trouble - except the CD changer tends to skip.

But I'm not running the stock suspension - I have the PSS9's and RS bars. Shocks and bars are set to medium. I don't have axle hop or excessive harshness - but maybe I'm just used to the firm ride.

When I first changed the suspension I had 44 psi rear - and the ride was jolting harsh. Reducing the pressure help the ride a bunch.

Are you a member of the Mav Region PCA? Have we met? I met George Abdalla last weekend at MSR. Maybe we should have a N.TX 993 confab sometime.

Ben

KC993

Ben,

I run MRPCA for years and used to be an instructor until we have 2 kids and need to cut back. KC is Kevin Chen, George and Glen both know me.
I also have PSS9 in my car. <img src="graemlins/jumper.gif" border="0" alt="[jumper]" />