RickGrimes

Hi

I had my CTT serviced at my local main dealer yesterday. Believe it or not the service was (slightly) cheaper than the local Porsche indy.

Anyway. They said my tyres are not "N" rated and therefore not Porsche approved.

I recently replaced all 4 with Avon ZX7's. I have been impressed with wet and dry grip so far as well as road noise.

This is the blurb from Avon's website......

"Designed for medium and large SUV fitments, the ZX7 – Avon’s first ultra-high performance SUV tyre – offers outstanding grip ('A' grade wet grip) and handling"

Plus Avon's are original fitment for Aston Martin

So the guy in Porsche Dublin made me think there was an issue with these tyres.

But there's not.....right?????

Andy E.

For years now, Porsche has always rated various tire brands for their N-approval rating. This rating system assures the Porsche owner that the specified tire has been fully tested and approved for use on that specific vehicle.

I've heard many stories from tire mfr reps to dealer SA's that using a non N-rated tire on your Porsche can void the factory warranty. When I've asked for literature to substantiate this claim, silence usually ensues.

At a local PCA event a few years back, an invited Pirelli rep told us that the N-rated tire has a special tire bead design that properly fits on the Porsche rim. This prompted me to section through a used N-rated tire and a non N-rated tire in order to see if this was true. It was not as both were identical in shape and in dimensions. Does this mean that the rubber compound could be different between the two? Perhaps...

Pirelli, Continental and Michelin will produce the exact same model tire as an N-rated version, but will sell it for 10-15% less. Does this mean that the non N-rated version of the exact same model is inferior in quality? You be the judge.

Unless you plan to track your Cayenne or frequent the Autobahn, you have nothing to worry about. The only exception to this would be purchasing and mounting low-cost Chinese tires on your car. Do some research and you'll see that you probably have a better chance of winning the lottery than finding a set of tires that won't give you problems. My $0.02

RickGrimes

Hi Andy

Track - No
Autobhan - I wish

Thanks for the reply. Nice to have a bit of reassurance.

RG

ScootCherHienie

There is ONE thing to worry about... the tire's load rating. You may find tires that are the right size, but they may not support the weight of a fully loaded Cayenne, especially 955 and 957. 2000 pounds per tire would probably be about right, 1750 pounds per tire might be easier to find and still OK from a load point of view.

Petza914

I've been a Porsche owner for 30 years (currently have 5) and have never had an N rated tire on any of them at any time, and I'm still here to make these posts

You're fine.

RickGrimes

S.C.H. -

The tyres I had fitted are indeed "XL" which obviously means they are reinforced for a heavier load. Most SUV's and people carriers here are fitted with them

Thanks too Petza - I hope to be still wearing out rubber on Porsches in 30 years time

RG

Petza914

in addition to the XL, there's an actual load index number on the sidewall. The tires on my Cayenne are rated a 107, which, when you look up a load index rating chart equates to 2,149 lbs so the 4 of them should support about 8,600 lbs. They also carry a Y speed rating, so I'm good to 186 MPH. Nothing like overkill in both categories

RickGrimes

Hi

Thanks for that. Just checked and mine are 106Y so I reckon I'm good too

CarGuyNVA

Certainly non-'N' rated tires can and do perform fine on Porsche vehicles, but according to this Tire Rack tech article there are some differences between the 'N' and non-'N' versions of a tire. Interesting read...

https://www.tirerack.com/tires/tiret...jsp?techid=26&

user 83838290

I had and still have a couple of sets of N rated tires and also non N rated tires both summer and winter variety. This on two turbo pigs.

I'm still here after very frequent trips with speeds above 270kph (~170mph) with at least three sets of non N rated tires, driving like a maniac around a track, puddling in mud deeper than wheels themselves etc. I reckon I'd notice a difference if there was one.

Forget about what the dealer told you.

RickGrimes

I don't know if I'll get the chance to test out those speeds in the CTT but thanks for the info

CaptainGSR

Rick, the correct answer is: ask your current insurance company (in writing / via email if you can).

FYI: in France, the tires only have to be of the approved sizes, speed and load ratings for the specific vehicle (meet or exceed the last two). In the case of a Cayenne, they also have to be "XL" rated. My insurance company officially does not care about the N-rating nor the Brand.