Do you guys really think there's a real benefit or is it all marketing hype? Would you run a non-N rated tire on the street? On the track? Anyone ever hear of a "mishap" that was caused by the use of non-N tires?

I see lot's of P-Cars at the track with race tires that obviously aren't N-rated. If non-N rated tires are ok for race tires, why not for street tires?

 

Tire Rack and Porsche's opinion

 

Porsche works with original equipment tire manufacturers, and when they test a tire that meets their requirements, and is priced right by the manufacturer, they use it. In return, they mark it as tested, that is N-rated. They then put out the fact/hype (you pick) that says "hey, the n-rated tires are tested by us" (and met our procurement requirements....). Of course, that means the non n-rated tires are just that, not rated by Porsche. They are well tested by the manufacturer, used by thousand of high performance vehicles...what do you think?

 

Bull,
Your comments get right at the heart of my question. What I don't know is what changes are made to the tires as a result of the testing. Based on test results, do they make changes to the tire design? Compound? Manufacturing process? Or do they just stamp the N rating and jack up the price.

I've seen many P-Cars at the track with non-N rated tires and haven't heard of any incidents that are caused by the use of non-N tires. So I can't help but ask "What's really different?"

 

My guess is that N-rating simply means they have shielded themselves from liability should a high-speed incident occur that was related to tire failure (perhaps this applies more to the speeds regularly achieved in europe and is largely a moot issue in the US). Think about it: at least the factory can say, "had they been using tires 'designed' for the car, this may never have happened." Who knows what the factory's input is on the design/manufacture ...prob none. The rating is most likely applied after an existing tire has been "passed" by the factory tests and deemed acceptable.

Edward

 

I believe Edward has it right. The only difference is that N rated tires have been tested by the Factory and used on new cars. Unrated tires are simply that, not rated. There has never been any listing of "tested and failed" tires that I could ever find.

There are so many industry/regulatory tests and ratings that can generally be relied upon that the N rating is of little or no added value to me. I can't imagine selecting a tire that was designed many years ago, N rated, and is at it's end-of-life in the product mix of a company over a new, more modern offering that hasn't been tested by Porsche.

 

You also have to consider that the latest "N" rated tyre will have been tested on the latest Porsche's, so who's to say they perform as good with older models Porsche's?
What works on a 997 may not work as well on a 993. Just my $0.02.

 

For more input, search on RL for responses from Viken on this exact topic. I can't remember his conclusion but I do remember it being covered.

If Porsche rejected a tire that it tested, I don't think I'd want it on my car. N rated gives you another data point in your decision process.

 

Perhaps wise to bear in mind that not only do Porsche update the approved tyre list in summer and winter, but they issue model specific TSBs which detail updates to particular models.

The last 993 summer tyre TSB was '04, so is a source of reasonable available tyres suitable for the 993. It bears an uncanny resemblance to the contemporary 996 one.

Here's the narrow body one .. you'll have to do the formatting, sorry ...

Approved Summer Tire Makes and Types
Tire Sizes Manufacturer and Type
Bridgestone Expedia S-01 N2
Bridgestone S-02 N3
205/55 ZR 16 1 Continental SportContact CZ 91 N0
and Continental SportContact N1
245/45 ZR 16 1 Michelin MXX3 Pilot SX N1
Michelin Pilot Sport N2
Pirelli P-Zero Asimmetrico N2
Toyo Proxes F1 S N0
Bridgestone Expedia S-01 N1
Bridgestone S-02 N3
Bridgestone Potenza S-02A N4
Continental SportContact CZ 91 N0
Continental SportContact N1
205/50 ZR 17 1 Continental SportContact 2 N2
and Dunlop SP Sport 8000 N0
255/40 ZR 17 1 Michelin MXX3 Pilot SX N0
Michelin MXX3 Pilot SX N1
Michelin Pilot Sport N2
Pirelli P-Zero Asimmetrico N1
Pirelli P-Zero Direzionale N2 2/Asimmetrico N2 3
Pirelli P-Zero ROSSO N3
Toyo Proxes F1 S N0
Yokohama A-008 P N1
Footnotes:
1 = Not for 911 Carrera RS
2 = For front axle only.
3 = For rear axle only.
Summer Tire and Wheel Summary
Tire Sizes Manufacturer and Type
Bridgestone Expedia S-01 N0 4
Bridgestone S-02 N1
Bridgestone Potenza S-02A N3
Continental SportContact CZ 91 N0
225/40 ZR 18 Continental SportContact N1
and Continental SportContact 2 N2
265/35 ZR 18 Michelin Pilot Sport N1
Pirelli P-Zero N0 4
Pirelli P-Zero Asimmetrico N1
Pirelli P-Zero Asimmetrico N2
Pirelli P-Zero Asimmetrico N3
Pirelli P-Zero ROSSO N4
Footnotes:
4 = Only for 911 Carrera RS M.Y. 1995.

HTH, cheers, Maurice

 

i cant speak to the track part, but for the street, why NOT use N-rated? sure, it might be marketing hype, or maybe it isnt....but the price different doesnt seem significant enough to risk it....

 

Yep, there is the "list", with many of those "tests" dating back to '95 and prior, when the tires where OE.

 

No reason NOT to, just no reason to go out of the way to do so.

 

ok, but how would you determin which tires Porsche has rejected. I think the liability issue is the most likely reason.

do the cup cars run n rated tires?

 

What makes one think that Porsche has ever rejected ANY tire where the procurement deal was satisfactory and the tire met minimum requirements? Or, put another way, if they rejected a tire, would it be for price/supply reasons, or for actual lack of tire performance.

If you look at the "N lists" supplied above, there are some poor performing tires by today's standards, or tires with significant trade-offs between grip and tread life, etc. Wouldn't one first need to know the spec that each N-rated tire was tested against?

No R-Compound or race tire is N-rated that i have ever seen.

 

There are times when one *should* buy factory OE, and then there are times when it makes little to no sense. N rating is the latter. Does anyone really think that the garden-variety 911 is soooo special, unique, tempermental, or design-specific that the car is somehow hampered by not using their magic-formula rubber? Think about this, really. There are crap tires, great tires, and lots of very good tires in between, each to suit one's climate and driving styles. And these develop and improve daily. One should simply choose accordingly.

Edward