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Question: What do the different 'N' ratings on car tyres mean?

My tyres need replacing and the rears for example are 295/30 ZR18's but also come with an N3 rating.

I have seen various options from different manufactures where some are a N1, N2 or N3 so which is best?
I understand the other numbers but what significance does this number play?
The car is a Porsche 911 and i know i need specific tyres with the Porsche fitment because the Porsche rims.

Is N1 the better tyre or the N3?
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Sports cars are often described as vehicles that "stick to the road." Sports car tyres make a major contribution to this phenomenon. These tyres 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 tyre design.

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





The focus in recent radial tyre development for Porsche vehicles has primarily included optimum handling on dry surfaces and the safest possible behavior on wet surfaces, even at high speeds. tyres 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 tyres they use on their vehicles.

Tyres may be specified for a particular vehicle or range of vehicles and must successfully pass the tyre 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 tyres meet Porsche's noise, hydroplaning and handling requirements. Prototype tyres will also be evaluated to assess their high-speed durability, uniformity and serviceability. Upon test completion, the tyres will be released for production.

Production tyres 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 tyre'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 tyre design. As that design is refined externally or internally, the later significant evolutions will result in a new generation of the tyre to be branded with N-1, N-2, N-3, etc., in succession. When a completely new tyre design is approved, it receives the N-0 branding and the succession begins again.

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

It is also important to know that while Porsche N-specification tyres have been fine tuned to meet the specific performance needs of Porsche vehicles, the tyre manufacturers may also build other tyres featuring the same name, size and speed rating as the N-specification tyres for non-Porsche applications. These tyres 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 tyres. Using tyres that are not N-specific is not recommended and mixing them with other N-specification tyres is not permissible.

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

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