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It's not that the system is outside of the mythical "3%" varience... it's that for the AWD system on the 996 to work it has to have the rear wheels overdrive the front's.
I don't recall the exact dimensions but I think the 245/35 PSS is like 813 revs/mile and the 305/30 PSS is like 800 revs/mile so the front diff won't work until the rear has already lost traction.
For the AWD to actually work you'd need the rear to be > 813 revs/mile in this 19" PSS example.
It's not that the system is outside of the mythical "3%" varience... it's that for the AWD system on the 996 to work it has to have the rear wheels overdrive the front's.
I don't recall the exact dimensions but I think the 245/35 PSS is like 813 revs/mile and the 305/30 PSS is like 800 revs/mile so the front diff won't work until the rear has already lost traction.
For the AWD to actually work you'd need the rear to be > 813 revs/mile in this 19" PSS example.
So please excuse my ignorance as I havent done much research and I am still studying. The diff needs to work with minimal diff in diameter size?
I am assuming if this is the case I better use 295 rears then 305?
295's still aren't any better. That's why so many people have been looking for alternatives. There isn't a great 19" tire option that keeps the AWD functional these days. Check the Sport Contact 6 thread for people trying to import a new 325/25R19 from Europe to fix the issue.
Time for an update. I was never happy with the fitment on my ADV.1's or the concave profiles I was able to get with a monoblock. Went more aggressive on the offsets with a new 2-piece forging 1221 developed that allows them to get a concave profile into the front wheel and the rear is the deepest i've ever seen on a 996TT. Weight came in the same as my ADV.1 monoblock (same diameter and widths) which in a modular wheel is just kind of nuts.
Had to do the front radiator clearance mod for the front offsets, roll the front fender a bit more at the very front edge as they were catching the tire but the fitment is perfect now and no rubbing with 245/35 & 305/30 PSS's. Going 12mm more aggressive on the front ET compared to my ADV.1's you can really feel the difference in steering weight on center and just off center with the increase in track width. I was actually really surprised how much of a difference it made. Hope you like!
