Understanding Porsche N spec Approval when Choosing Tires

July 25, 2008

For those of you that have been long-term readers you’ll remember a post I did some time ago where I offered my research services to answer any Porsche related question. That post, “I’m not a Porsche Expert, but I Play one on the Internet” continues to generate a number of questions and I want to do my best to keep answering them for you.

In my opinion, it’s a win-win situation. You get great content to help research a specific Porsche topic and during my research I learn even more about Porsche Cars, Products and LifeStyle. Please feel free to keep sending your questions in by simply commenting on this article or any other on the site (I see them all.) If I don’t answer them directly, here on the web-site, I will email you back personally whenever possible.

Today’s question has to do with finding the right tire for your Porsche. More specifically:

“What does it mean for a tire to have a Porsche N spec approval?”

A Porsche N spec approved tire is one that has passed a series of difficult and diverse test designed by Porsche engineers to ensure maximum performance and safety under a wide range of driving conditions. To qualify for this approval and “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.” In some instances specific tires will only be approved for specific Porsche applications or models.

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.

Let’s look at some of the tests required by Porsche for N spec approval:

SPEED: The tire must be capable of safely handling the Porsche vehicle at any speed while allowing it to reach its top speed on a track or the German Autobahn.
NOISE: As tires continue to grow in size and width, noise suppression becomes more and more important. Generally speaking, Porsche performance tires are low profile and very soft. This makes it even more difficult to manage road noise. You can rest assured that those tires with a Porsche N spec approval will be as quiet as possible.
HYDROPLANING: 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.
HANDLING: I’m not sure this particular heading requires any additional explanation. Your tires provide the grip that keeps your Porsche “stuck” to the road. Poor tire construction, soft sidewall, tires that are too firm, etc. all these things will lead to reduced handling and possible safety concerns that can be avoided by choosing a Porsche N spec tire.

Once a tire has been approved by Porsche it is branded with the N spec approval. 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 important to note that certain tire manufacturers may produce the exact same tire in name, size and speed rating as those that have the N spec approval. However, if they are not branded with the N spec approval than it is very likely that they do not adhere to the same rigid production and quality requirements demanded by Porsche.

According to a recent Porsche owner’s manuals, if you do run Porsche N spec approved tires on your car, it is always recommend that your tires be replaced in pairs (one axle at a time.) In the event 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.

Here’s a list of some of the more popular Porsche N spec approved tires:

There are many, many more tires, than those listed above, that are Porsche N spec approved. If you are researching tires, one of your best bets is to check out The Tire Rack as you can look up your vehicle by make, model and year. The resulting list of tires will provide you with various information including whether the tire is a Porsche N spec approved one.

As a conflicting and interesting end to this post, I recently replaced the tires on my 1997 Porsche 993 C4S. After days of research I ended up selecting a tire that was NOT Porsche N spec approved. At the end of the day I received an excellent tire that performs as well, if not better, than the N spec approved tires the car was originally equipped with. Here’s a review of the Sumitomo HTR Z III tires I chose.

Don’t forget, if you have more questions you would like researched and answered, please ask below or by sending me an email to ask at 993C4S dot com.