Clifton

*smacks forehead*

Using Non-N tires will actually cause the car to gain self awarness, shut down and call Porsche road-side assist. You've all been warned....

ADias

Are you so sure I am wrong? Yes, it is unlikely that a warranty claim may be denied on tire type but you cannot say it cannot happen. My dealer does not install, per PCNA regs, non N-rated tires. I know this for a fact.

Regarding insurance claims there have been examples of insurance cos denying coverage due to tires not approved by the manufacturer and not necessarily PAG.

Clifton

Your dealer will not install OEM parts (non-porsche) either. That does not mean they will or can void your warranty if you use another brand air/oil filter.

In those examples I bet it was because the tries were not DOT (street legal), i.e., slicks or racing tires. No manufacture would approve those for the road and no insurance company would cover your claim if you had an accident with them on (huge loop hole).

Non-Ns are DOT certified - case closed and covered by insurance and warranty.

Go fish.

ADias

^ I expressed a POV, perhaps overly cautious, but nothing wrong with it if one follows it. Why do you have to be so abrupt and revert to personal attacks?

brt3

Interesting concepts. In America, given all the legal BS, it might be better to look at this more closely -- and I'd love to hear a product liability attorney's take on this.

First off, I'm damnably ignorant about Porsche and the tire issue. With that out of the way, I do wonder if there's some validity to this point. Certainly it would be valid if, for example, you were using a tire whose speed rating didn't match the capabilities of the car. The same would apply for changing your own oil, but using a grade/viscosity of motor oil that was outside Porsche's recommended specs.

All I'm saying is it's an interesting concept, and one that I wouldn't dismiss out of hand.

From TireRack: http://www.tirerack.com/tires/tirete....jsp?techid=26

Porsche N-Specification Tire Approvals

Sports cars are often described as vehicles that "stick to the road." Sports car tires make a major contribution to this phenomenon. These tires are very complex products meeting numerous, largely contradictory demands. Finding the proper structure that balances these demands for any given application is the great challenge in tire design.

Porsche designs and manufacturers some of the highest performance vehicles in the world. Because of the integral role that tires play in vehicle performance, Porsche has integrated tire development throughout their process of vehicle development. To be an Original Equipment tire provider on a Porsche vehicle or be approved by Porsche for the replacement market requires the joint product development efforts of the tire engineers working alongside the Porsche vehicle engineers.

The focus in recent radial tire development for Porsche vehicles has primarily included optimum handling on dry surfaces and the safest possible behavior on wet surfaces, even at high speeds. Tires developed by various manufacturers, in concert with Porsche, offer a specific set of wet grip properties which few, if any, other automobile manufacturers demand in equal measure from the tires they use on their vehicles.

Tires may be specified for a particular vehicle or range of vehicles and must successfully pass the tire company's laboratory tests to assure that they would be capable of adequately supporting the Porsche vehicle while allowing it to reach its top speed on the German Autobahn. Additional laboratory, test track and race track tests are conducted to confirm that the prototype tires meet Porsche's noise, hydroplaning and handling requirements. Prototype tires will also be evaluated to assess their high-speed durability, uniformity and serviceability. Upon test completion, the tires will be released for production.

Production tires that have passed all of the tests and received the engineering department's release can be branded with an N-specification. The N-specification brandings include: N-0 (N-zero), N-1, N-2, N-3 or N-4. These markings on a tire's sidewall clearly identify them as approved by Porsche for their vehicles. The N-0 marking is assigned to the first approved version of a tire design. As that design is refined externally or internally, the later significant evolutions will result in a new generation of the tire to be branded with N-1, N-2, N-3, etc., in succession. When a completely new tire design is approved, it receives the N-0 branding and the succession begins again.

It is recommended that only matching tires be used on Porsche vehicles. Since many Porsche vehicles are fitted with differently sized tires on their front and rear axles, this means matching the tire make, tire type and N-specification. If a vehicle was originally delivered with N-specification tires that have been discontinued and are no longer available, it is recommended to change all four tires to a higher numeric N-specification design appropriate for that vehicle. Mixed tire types are not permissible.

It is also important to know that while Porsche N-specification tires have been fine tuned to meet the specific performance needs of Porsche vehicles, the tire manufacturers may also build other tires featuring the same name, size and speed rating as the N-specification tires for non-Porsche applications. These tires may not be branded with the Porsche N-specification because they do not share the same internal construction and/or tread compound ingredients as the N-specification tires. Using tires that are not N-specific is not recommended and mixing them with other N-specification tires is not permissible.

Tires should be replaced no less than in pairs on one axle at a time. Only tires of the same tire make and type must be used. However, in case of tire damage such as cuts, punctures, cracks or sidewall bulges that cause a single tire to be replaced for safety reasons, the remaining matching tire on that axle must not exceed 30 percent wear. If the remaining tire has more than 30 percent wear from new, it should also be replaced. Handling inconsistencies may result if this is not done.

Initially, new tires do not offer their full traction. Drivers should therefore drive at moderate speeds during the first 60-100 miles (100-200 km). If new tires are installed on only one axle, a noticeable change in handling occurs due to the different tread depth of the other tires. This happens especially if only rear tires are replaced. However, this condition disappears as new tires are broken in. Drivers should adjust their driving style accordingly.

NOTE: The last two paragraphs are excerpts from recent Porsche vehicle owner's manuals.

Edgy01

Not long ago one of our PCA members horribly mismatched tires on his 996 Turbo. The tire shop warned him against it but he ignored them. He participated on a relatively spirited run with many of us the weekend after the tire changeover. He absolutely was scared to go over 60 because of the way the car was behaving. Sure enough, it was the tire mismatch.

We demand so much from these cars today. Their performance capabilities are way up there, but only if you follow some rules. Tires can make a significant difference in these cars.

(BTW, our guy with the 996 Turbo went back and got his tire issue squared away with 4 matching tires--and he was all good again).

obsessedone

Lot's of good input here.

1) Check tire pressures are correct - not likely the issue but free so double check the pressures.

2) Wandering and cording inside of rears both suggest car has alignment issues - wandering from front toe and cording edges from camber. Car may have been given a track alignment at some point but maybe just hit a pothole or curb. Get a fresh "street" alignment.

3) If alignment alone doesn't resolve the issue fully, get matching tires. Mismatched tires are never a great idea, but on a car with uneven weight distribution and front and rear tire sizes that have been engineered to help overcome the poor handling characteristics of a heavy rearend it is even more risky than in most cars. Still the alignment is the likely cause of the handling issue you inquired about in OP.

No HTwo O

Be careful Red Horse, PCNA made you sign a Non Disclosure Letter to make this happen. You are not suppose to be babbling this on the internet. I'll report you!

997CS4

At high speed (>160 mph) on German autobahn there is a noticable difference whether the suspension is in nomal, sport, or sport plus mode. In sport plus car is solid as a rock; in normal mode at those speed car feels a little less stable (rides higher).

signature65

Ok.....this is getting heated here, here are the findings.

N rated tires are preferred but not necessary

Matching tire sets are more important than N rated tires

Alingment should be done after every tire change out

Thanks guys for all your responses,

obsessedone

Once alignment is properly set for your usage (track or street) it should be OK for a long time barring an impact that causes the alignment to go out - a simple tire change does not require a realignment. On the other hand, a single hard whack on a pothole can screw up your alignment, especially with low profile tires that do not absorb much of the impact.

signature65

Ya I have no baseline on this car since I have only owned it for 2 weeks so far. Definately need to get it aligned.

MUSSBERGER

Except when he says don't mix tires

alexb76

Correct! I think you got the main points. 100% try to match the tires and you'd be set. Cheapest N-rated is Bridgestone RE050, and wish you went with those instead of Hankooks, but since you just got Hankooks, might as well just go all Hankook at 4 corners... then decide next time around if you wanna go all N-rated.

Macster

When I took my 996 Turbo in for new rear tires the service department told me it may not be able to match the N numbers of the rear tires and if so the fronts would have to be replaced.

Before I could even get started objecting I was told because the car was covered by CPO warranty that if no rear tires were available to match the N numbers of the front tires the front tires would be replaced at no cost to me to match the rear tires.

Ok, says I and left the car. The service department did have to scratch around and found a new pair of rear tires that matched.

Sincerely,

Macster.