[rizzo]

Anyone here have experience with either of their all terrain tires from Pirelli?

I can't imagine there being much difference for what I am going to do with them so here is another part of my question.

With 18 in wheels:

The ATR is only available in the 255/55-18

The A/T is only available in the Porsche recommended 235/60-18 size

Will half an inch of sidewall height really make that much difference for going off road?

I'm headed to Big Bend National Park in Texas and will head down River Road (apx 60 miles). There are parts of this road that you can average 15mph. It's not a hard core off road trail though there are some parts that all terrain tires may be helpful.

Any opinions on whether or not I really need the 235's?

Thanks!

This post has been edited by rizzo: May 03, 2009 - 11:59 AM

[darrinsmith]

Hi Rizzo,
Yeah finding a real off road tyre is hard for these cars.
My off-road 18" wheel actually have Pirelli P-zeros!
In boggy sand you can let them down o as low as 16PSI.
I recently climbed a really steep rocky "goat track" towing my 1.2 tonne off road camper trailer with these tyres, no problem.
Just crawled up to the absolute amazement on my camping buddies (1 x Toyota Landcruiser 110 series, and 1 x Hilux).
Back on topic though, where you need sidewall is when you let you pressure down, I have sucessfully 4wd'd in sand in the 19" 275/45 tyres at 18PSI.
It's all about the "length" of you tyre track, not the width.
Don't forget if you get suck in Sand you can feather the throttle to defeat the traction control (to a certain extent) to keep the momentum up without spinning the wheels.
With rocks, let you pressure down a bit, but GO SLOW, popping the bead is a real hassle (although the turbo's built-in air compressor is really handy in this situation!).
These cars are awesome off-road, get out and enjoy!
Cheers
Darrin Smith
Perth Western Australia
"Home of the most beautiful beaches in the world!" (that you can drive your 4WD on!)