Looking for new tires for a new set of rims soon, I believe some have used these tires so I want to make sure they will work with AWD.
Fronts 245/40/18 overall diameter is 25.7
Rears 315/30/18 overall diameter is 25.5

Any info and feedbacks from those that have used them is appreciated!

 

they are fine. Fronts will spin a bit slower, which ads minuscule drag on the viscous coupling, but doesn't harm a thing. that is the way you want it, so that if the fronts lose traction and slip, or spin slower than the rears, torque is transferred to the fronts more effectively.

 

as dave says those sizes will work fine, but that is also dependent upon what size rims you'll be using?

the best size for day to day use will be either 225/40 or 235/40 X 315/30, and either of those choices will fit on either stock twists or gt2 wheels or similarly sized 8.5 or even as i run, 9 X 12 rears.

most find through trial and error that it's very difficult to improve upon porsche's engineers decisions on those sizes when they designed the car(s). the gt2 size is really optimal i have found, and if you are custom ordering your rims? you can obviously customize the offsets to accomodate the best offsets so that you'll achieve the *proper* stance and plant, while following the wisdom of those that have tried this before you

 

I plan on running ccw classics made in GT2 offsets, because as you said they seem to work best for these cars. I'm probably going to run a 9" front rim that's why I was thinking with going with the 245 in the front.

 

careful with 9" and gt2 offset up front if you have OEM struts. GT2 has coilovers with much different clearance (much smaller diameter spring) and runs an 8.5 wheel with those offsets

 

a 9 in front is fine I run it with a 40 offset with a 235/40. its perfect for me.

 

I use that setup, and I have a little over 2 thousand miles on them. They are a great track/street compromise.

 

I thought I'd read that ccw wouldn't sell classics for 996 any longer? Has that changed?

 

Yes they have changed the design with stronger barells in order for them to work with our cars

 

It was never a barrel problem, it was the center. As if a year or so ago, they reintroduced them for 996.

 

Good point! this is why I had to get 5mm spacers with my 9" CCW c14s they barely touch the spring Seat on the stock strut. No problem with the coilovers installed.

 

Yes correct sorry worded it wrong

 

Oh sweet! I know what wheels I want now! Id thought it wasnt an option for us.