New Tyres

[xenon]

The interweb has this to say:

Porsche N-rated tyres.

Porsche designs and manufacturers some of the highest performance cars in the world (with the exception of the butt-ugly Cayenne). All this design and performance is worth nothing if you put cheap Korean tyres on your Porsche though, and because of that prospect, Porsche introduced the N rating or N specification system. In order for a manufacturer to be an OE (original equipment) supplier of tyres for Porsches, they must work with the Porsche engineers at the development and testing stage. They concentrate on supreme dry-weather handling but they also spend a considerable amount of time working on wet-weather handling. Porsches are typically very tail-heavy because of the position of the engine relative to the rear wheels, and with traction control off, it's extremely easy to spin one in the wet. Because of this, Porsche specify a set of wet-grip properties which is way above and beyond the requirements of any other car manufacturer.
OE tyres for Porsches must successfully pass lab tests to prove that they would be capable of adequately supporting a Porsche at top speed on a German Autobahn. Once the lab tests are done, they must go on to track and race tests where prototypes are evaluated by Porsche engineers for their high-speed durability, uniformity and serviceability. If they pass all the tests, Porsche give the manufacturer the go-ahead to put the tyres into production and then they can proudly claim they are an N-rated Porsche OEM.
The N-ratings go from 0 (zero) to 4, marked as N-0, N-1 etc. This N-rating, stamped into a tyre sidewall, clearly identifies these tyres as having gone through all the nauseating R&D and testing required by Porsche as described above. The number designates the revision of the design. So for a totally new design, the first approved version of it will be N-0. When the design is improved in some way, it will be re-rated as an N-1. If the design changes completely so as to become a totally new tyre, it will be re-rated at N-0.
If you've got a Porsche, then you ought to be aware that as well as using N-rated tyres, you ought to use matching tyres all around because many Porsches have different sizes tyres front and rear. So for example if you have a Porsche with N-3 rated tyres and the rear ones need replacing but the model has been discontinued, you should not get N-0's and put them on the back leaving the old N-3's on the front. You should replace all of them with the newer-designed re-rated N-0 tyres. But then you own a Porsche so you can certainly afford four new tyres....
One final point. You may go into a tire warehouse and find two tyres with all identical markings, sizes and speed ratings, but one set has an N-rating. Despite everything else being the same, the non-N-rated tyres have not been certified for use on a Porsche. You can buy them, and you can put them on your car, but if you stuff it into the armco at 150mph, Porsche will just look at you and with a very teutonic expression ask why you didn't use N-rated tyres.






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[Neil Haughey]

Loads of car manufacturers have special to make/model tyres and Porsche is no different.

AFAIK none of the current N rated tyres have been developed on or for the 944 which is hardly surprsing for a 16+ yr old car. You could try and fit N rated models that used to be approved fitments on the 968 but then you fill find that these tyres are also 15 yr old technology (assuming you can get them) and will almost certainly be outperformed by more modern tyres.

Toyo which is very popular tyre amongst many of us used to make a F1-S with N designation for the 968 but this tyre was superseeded by the T1-S and recently has been made defunct again so 2 generations away from a N designation.

The idea that Porsche out of the kindness of their heart spend money testing tyre manufacturers tyres like some kind of super TuV or MIRA organisation is hilarious. They do it like any other manufacturer as part of a process where the tyre supplier wants to become a OEM supplier.

To close on this I will say one thing. The only tyres I have fitted in the past 7 years that had N designation where contisportcontacts that had easilly the most amazingly bad wet weather performance of any tyre I have fitted on any car.

 

[MarkK]

Thats really odd,i have Contis (Nspec) allround on my standard 44 turbo and our 964 and they are both great in the wet,maybe they have changed something on the Contis since???

 

[Riverside]

ORIGINAL: Fen

ORIGINAL: Riverside
I've always put N-rated tyres on my Porsches & I guess I've paid a little extra for peace of mind. There are certainly tyres that fit that are suitable & may be better value for money.

As I said buy them if you want as it won;t do any harm but they are totally unnecessary.

To paraphrase IBM: Nobody ever got fired for buying N-rated tyres.

 

[Hilux]

If there wasnt an N rated tyre for the 944 and the original tyres fitted on the 944`s are not made any more then why bother?? A certified manufacturer of tyres that meets type approval will be fine. Look at the debate re tyre types on this forum, the preferred types are not N rated, I certainly wont be lying awake worrying about it.

Do the top beemers and Audis etc spec N rated?

Sounds to me like N rating was primarily to stop rear engined 911`s going into hedges backwards ie: it made your average 911 owner think about tyres and reduced the number of instances (and reputation)

 

[TTM]

ORIGINAL: interweb
if you have a Porsche with N-3 rated tyres and the rear ones need replacing but the model has been discontinued, you should not get N-0's and put them on the back leaving the old N-3's on the front. You should replace all of them with the newer-designed re-rated N-0 tyres.

Interesting - is there scientifical evidence backing up this assertion ?

 

[Hilux]

Only Porsches research (see my post above)

 

[TTM]

Yes, whence my question.

 

[Fen]

In my (recent) experience people should have been fired for choosing IBM, but the sentiment is correct regarding N-rating.

In answer to the Audi/BMW question, no, N- rating is exclusively Porsche. I don't believe that Audi have an equivalent and since I own what is (for another week) the most powerful and heaviest car they have ever produced then I would expect to know. I also don't know of BMW having an equivalent in my reserach into buying an M car, but they might. Lesser BMWs all use run flats now and you do not have to replace with the same, though you do have to relace all 4 if you remove run flats from one corner or axle.

That said there are some tyres that the tyre manufacturer will list as BMW specific or even RS6 specific. Whether they are actually the same as the equivalent non-specific I would suggest is worth questioning. I suspect that what they mean is "this model was fitted to some cars by the factory".

 

[Diver944]

ORIGINAL: Riverside

To paraphrase IBM: Nobody ever got fired for buying N-rated tyres.

Hmmmmm [&:] They gave me a nice cheque to leave without making a fuss and I don't have N rated tyres. Maybe if I did I would still be there [] I love IBM, they paid for LIL's engine []

Coming spectacularly back on topic I would not worry a jot about N rated tyres on a 944. The Porsche N ratings were brought out just as the 944 went out of production and the Factory Manuals mention one brand as being tested on 944s. I can't remember the brand without checking the manual but it was a long, long time ago in the early 90's and any modern tyre would easily surpass it in my opinion

 

[MarkK]

The "N" Contis are not expensive and are easy to get hold of i think they are a fair tyre for everyday and Porsche have destroyed a few sets and say they are up to scratch??I wouldn't lose any sleep if they didn't have N rating but why not if they are available-all adds to the Porschyness[]

 

[Neil Haughey]

ORIGINAL: MarkK

Thats really odd,i have Contis (Nspec) allround on my standard 44 turbo and our 964 and they are both great in the wet,maybe they have changed something on the Contis since???

There has been 2 newer generations of contisport contact since then. The ones I had where firstly normal contisportcontact then the "special" N ones. The differences where the N ones looked about 15mm wider and had a softer compound then the normal contisportcontacts. Grip in the dry was fine, and when warm they worked half way OK in the wet. The problem was a complete lack of grip when cold on a wet road. Remember that 4 or 5 years ago companies like Toyo where already making tyres with wet grip only slightly down on dry grip. I believe the mega soft side walls where also a problem since this meant that sudden weight transfer when cornering would likely ungrip the outside rear wheel in the rain.

The cars body roll was cut in half simple by switching to Toyo T1-S

 

[Neil Haughey]

ORIGINAL: Fen

In my (recent) experience people should have been fired for choosing IBM, but the sentiment is correct regarding N-rating.

I would add J2EE to that and possibly SOA. Interesting how what looks like a good idea evolves into massive bloatware just at the point when everyone is jumping on the bandwagon. I have a friend who was/is really interested in getting good with J2EE AJAX, javascript, webservices thinking it will earn him mega dosh basically all the buzz words. I told him to look at GWT and he hasn't spoken to me since!

Sorry if this sounds way of topic but I have been back in programming at the low levels of a real time system running on a tiny RTOS interfacing with loads of special devices. Reminded me that I actually really enjoy this sort of systems and software development and hate with a passion the corporate bloatware nonsense.

 

[MarkK]

Are they available in 16 inch dimensions(standard size)???

 

[Neil Haughey]

ORIGINAL: MarkK

Are they available in 16 inch dimensions(standard size)???

All of the conti's I had where stock 205 225 sizes on 16" rims. The 225 wide rears in the N spec looked as wide as T1-S in 245 width. Basically I tend to prefer stock sizes on the stock rims because there is less movement of the tyre in the rim. When I had 225 wide T1-S on the front it felt like the car was lurching a little in the corners. At the moment I am running 225 and 245 wide tyres but only because the recommended rim widths (for Hankook RS2's) line up nicely for 7" and 8" rims.

Strangely I have contipremiumcontacts on the Saab and these seem a massive step forward from continental tyres 5 years ago (they don't seem to last though), so I am thinking of trying the new sportcontact3 on that car with 17" rims.

The continentals though always had a very smooth ride and low noise which is why they work well on the Saab.

 

[Fen]

ORIGINAL: Neil Haughey

ORIGINAL: Fen

In my (recent) experience people should have been fired for choosing IBM, but the sentiment is correct regarding N-rating.

I would add J2EE to that and possibly SOA. Interesting how what looks like a good idea evolves into massive bloatware just at the point when everyone is jumping on the bandwagon. I have a friend who was/is really interested in getting good with J2EE AJAX, javascript, webservices thinking it will earn him mega dosh basically all the buzz words. I told him to look at GWT and he hasn't spoken to me since!

Sorry if this sounds way of topic but I have been back in programming at the low levels of a real time system running on a tiny RTOS interfacing with loads of special devices. Reminded me that I actually really enjoy this sort of systems and software development and hate with a passion the corporate bloatware nonsense.

I was talking IBM as a service provider rather than a hardware vendor. Bizarrely the organisation in question outsourced the support of their Dell hardware to IBM. Talk about the worst of both worlds!

 

[Diver944]

Yes, there is less clearance between the wheel and the arch on the nearside rear, it's all down to 1980's tolerances and sliderule instead of cadcam machines.

Odd that the old tyres didn't rub, are they definately the same size as before? Were the old ones plain Conti's and these are now N rated for Porsche. It has been noticed that some brands which are N rated are actually wider than the normal tyre

 

[bennyboy]

No they're definately the same - N2 Porsche specification. I waited ages for them. I can only assume the new tyres with extra tread and no wear are slightly larger than the 8 year old worn tyres they replace. Rich Salmon suggested I adjust the rear end a touch using the accentric (spelling?) bolts. Can anyone point me in the right direction for instructions?

 

[sawood12]

Seems a bit like the tail wagging the dog to adjust your suspension to suit your tyres - at least before understanding what is different than before. What size tyres are you running?

 

[bennyboy]

At the back, 265/35/18, and the car is pretty low (cannot get a trolley jack under the sill), no spacers either. The car is perfectly level at the back (measure it) so it must be just this 'nearside rear' issue. It only rubs when cornering to the right at reasonable speed or when the car goes into a dip, but it serious enough to worry!