N rating on tyres
Discussion
Hi
1997 993 C2S
Can anybody clarify the N notation issue on tyres for Porsches.
I have a set of Michelin Pilot Sport (2003/4 vintage) (265 35 ZR18 Rear and 235 40 ZR18 front). It might be that I 'blind' but I cannot see any N notation ?
I am concerned about this is respect of insurance but cannot believe that tyre suppliers make tyres especially for Porsche ie with the N notation. Surely a ZR rated tyre is exactly that, ZR ?
I now see that 996 GT3 has M Pilot Sport as standard.
Nick
1997 993 C2S
Can anybody clarify the N notation issue on tyres for Porsches.
I have a set of Michelin Pilot Sport (2003/4 vintage) (265 35 ZR18 Rear and 235 40 ZR18 front). It might be that I 'blind' but I cannot see any N notation ?
I am concerned about this is respect of insurance but cannot believe that tyre suppliers make tyres especially for Porsche ie with the N notation. Surely a ZR rated tyre is exactly that, ZR ?
I now see that 996 GT3 has M Pilot Sport as standard.
Nick
N ratings work like this:
Porsche works with several manufacturers to supply tires that meet their requirements. For a given tire model (say Michelin Pilot Sports) an N designation is given if the tire passes Porsches tests. When the tire is given a new revision by the manufacturer (say, different compound, or belts, etc) Porsche will test it again and give it an incremental N designation. IE N1->N2. There is nothing to say that a tire without a Porsche N designation is inferior, but you have to ask yourself if you really want you and your car to be the testing grounds for that. I've heard it said that you don't even want to mix N designations of the same tire model on different axles as this may affect relative grip levels front and aft, etc.
hope that helps,
Paul
Porsche works with several manufacturers to supply tires that meet their requirements. For a given tire model (say Michelin Pilot Sports) an N designation is given if the tire passes Porsches tests. When the tire is given a new revision by the manufacturer (say, different compound, or belts, etc) Porsche will test it again and give it an incremental N designation. IE N1->N2. There is nothing to say that a tire without a Porsche N designation is inferior, but you have to ask yourself if you really want you and your car to be the testing grounds for that. I've heard it said that you don't even want to mix N designations of the same tire model on different axles as this may affect relative grip levels front and aft, etc.
hope that helps,
Paul
Setch993 said:
Hi
1997 993 C2S
I have a set of Michelin Pilot Sport (2003/4 vintage) (265 35 ZR18 Rear and 235 40 ZR18 front). It might be that I 'blind' but I cannot see any N notation ?
Nick
I also find your tire sizes interesting... My '96 C4S, and I thought all 993 S-bodies, rides on 225/40ZR18 front, and 285/30ZR18 rear. Perhaps the PO put different tire sizes on and it is these SIZES that do not have the N designation, hence you cannot see it stamped on the tire. Good luck
Paul
FWIW, on my Michelin Pilot Sports (17 inch on a 993), the N rating (in my case N2) is clearly displayed on a panel immediately after the tyre size (in my case, 205/50 ZR 17).
If you have the N marked tyres, you should be able to see it easily enough.
I know insurance companies can refuse loss-of-control crash claims if inappropriate tyres are fitted. However whether using a non-N rated tyre would be a problem is a matter of interpretation: assuming the tyre is of an appropriate size and the correct speed rating, it'd be hard to make a case that it was inherently less safe.
Obviously as a high performance car manufacturer, Porsche would prefer you to use tyres they've tested themselves - as they'll know that the car handles correctly on them. Do Porsche test every tyre on the market? Equally I'd be surprised if there weren't deals between Porsche and the tyre companies.
This is more of an issue for companies that Porsche haven't approved: if the Michelin Pilot Sport is an approved tyre and a common fitment, and therefore N rated Pilot Sports are easy to come by, I'd be asking questions why your tyres aren't N-rated. The Pilot Sports weren't only recently tested: my rear tyres are N2s and are a couple of years old.
By the way, anyone here know why 'N'?? Just curious... I would have expected a 'P' rating for Porsche-tested tyres. Or is there some simple German word beginning with N that explains it?
If you have the N marked tyres, you should be able to see it easily enough.
I know insurance companies can refuse loss-of-control crash claims if inappropriate tyres are fitted. However whether using a non-N rated tyre would be a problem is a matter of interpretation: assuming the tyre is of an appropriate size and the correct speed rating, it'd be hard to make a case that it was inherently less safe.
Obviously as a high performance car manufacturer, Porsche would prefer you to use tyres they've tested themselves - as they'll know that the car handles correctly on them. Do Porsche test every tyre on the market? Equally I'd be surprised if there weren't deals between Porsche and the tyre companies.
This is more of an issue for companies that Porsche haven't approved: if the Michelin Pilot Sport is an approved tyre and a common fitment, and therefore N rated Pilot Sports are easy to come by, I'd be asking questions why your tyres aren't N-rated. The Pilot Sports weren't only recently tested: my rear tyres are N2s and are a couple of years old.
By the way, anyone here know why 'N'?? Just curious... I would have expected a 'P' rating for Porsche-tested tyres. Or is there some simple German word beginning with N that explains it?
I believe that N rated tyres have a stiffer side wall than the equivalent non N. I can understand the need for this on a car with such unusual weight distribution. From experience, rear engined cars with large supple walled radials seem to shuffle along the road at low speed, almost as though it had buckled wheels.
A thought
Presumably when Porsche are 'asked/given' a set of tyres to evaluate they do not have an N rating. If no mods are required to meet the N requirement is it highly likely that N '0' and the test tyre are in fact the same. I find it inconceivable that a Tyre manufacturer would re-tool just to meet Porsche requirements (apart from a manufacturing run to impress the letter N on the side wall). The tyre market is bigger than Porsche and product transferability across manufacturers of other performace cars must a strategic aim of the tyre company. Niche marketed manufacture for Porsche might seem uneconomic in the context of world supply ?
The word 'may' might be important in the quote below.
All the same I prob will not risk fitting them (they are not on the car yet)
Quote fro helpful web link:
'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 permissable'.
Presumably when Porsche are 'asked/given' a set of tyres to evaluate they do not have an N rating. If no mods are required to meet the N requirement is it highly likely that N '0' and the test tyre are in fact the same. I find it inconceivable that a Tyre manufacturer would re-tool just to meet Porsche requirements (apart from a manufacturing run to impress the letter N on the side wall). The tyre market is bigger than Porsche and product transferability across manufacturers of other performace cars must a strategic aim of the tyre company. Niche marketed manufacture for Porsche might seem uneconomic in the context of world supply ?
The word 'may' might be important in the quote below.
All the same I prob will not risk fitting them (they are not on the car yet)
Quote fro helpful web link:
'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 permissable'.
RTFM.....
The numbers after N indicate at which point the development has got to. All Porsche approved tyres would have started at N0, and then as each tyre was changed and developed and tested by Porsche, the number changed in sequence -some tyres are on N4 now.
N0 tyres would have been early '90's, when N ratings started, so if you've got or have been offerd these, they are well past their sell by date.
N.B. Tyres have a shelf/on car life of approx. 5 years.
Rgds
Mel
The numbers after N indicate at which point the development has got to. All Porsche approved tyres would have started at N0, and then as each tyre was changed and developed and tested by Porsche, the number changed in sequence -some tyres are on N4 now.
N0 tyres would have been early '90's, when N ratings started, so if you've got or have been offerd these, they are well past their sell by date.
N.B. Tyres have a shelf/on car life of approx. 5 years.
Rgds
Mel
Hi
My point exactly.
If N-0 was allocated with no mods to the submitted test tyre, then to test tyre was to N spec already, the numerical sequence after that presumably relates to development of the same original tyre.
The tyres I refer to are 2004 vintage so are very current, they were fitted to my BMW 850 and were so new when I sold the car that I felt compelled to remove them for 'future use' (I am a Yorkshireman !).
I suppose issue here is that we will never get to know whether a manufacturer did or did not amend the original tyre to meet the N spec ? I bet Michelin will not answer this in the issue I have raised with them.
On a cynical note, I wonder whether N spec tyres are more expensive that the non N spec, but in fact the very same ZR rated tyre ? Are we being ripped off and 'forced to buy' N spec because of mantra or fact ?
If no price differential exists then so what, If it does ?
My point exactly.
If N-0 was allocated with no mods to the submitted test tyre, then to test tyre was to N spec already, the numerical sequence after that presumably relates to development of the same original tyre.
The tyres I refer to are 2004 vintage so are very current, they were fitted to my BMW 850 and were so new when I sold the car that I felt compelled to remove them for 'future use' (I am a Yorkshireman !).
I suppose issue here is that we will never get to know whether a manufacturer did or did not amend the original tyre to meet the N spec ? I bet Michelin will not answer this in the issue I have raised with them.
On a cynical note, I wonder whether N spec tyres are more expensive that the non N spec, but in fact the very same ZR rated tyre ? Are we being ripped off and 'forced to buy' N spec because of mantra or fact ?
If no price differential exists then so what, If it does ?
I had A008s on my RS - Nzero rated. Couldn't find any to replace the rears of the same rating -they'd moved to N1 by then. So first point to make - in the 8 years of that tyre's life between the time my car was built and when I was looking to replace the tyres, there'd been only one evolution. So don't automatically assume that because the car you're looking at has a low N number that its tyres must be ancient. Find out what the current N number is (call a tyre dealer) and also speak to the manufacturer's UK representative if you need to check just how old the set of tyres is.
Secondly, I spoke to Yokohama UK and Posche Cars GB and both told me that it was OK to mix the N ratings - as long as I had identical N rateed tyres on each axle. BUT IMHO the car didn't ever feel the same again.
Of course, it is still possible to buy a set of tyres that have sat on the shelf for a long time, especially if they are N rated and in a size that isn't too popular.
Finally, N rated Contis for my 911 are identical in price to the same non N rated tyres.
Secondly, I spoke to Yokohama UK and Posche Cars GB and both told me that it was OK to mix the N ratings - as long as I had identical N rateed tyres on each axle. BUT IMHO the car didn't ever feel the same again.
Of course, it is still possible to buy a set of tyres that have sat on the shelf for a long time, especially if they are N rated and in a size that isn't too popular.
Finally, N rated Contis for my 911 are identical in price to the same non N rated tyres.
Melv
Not sure they were answered actually, but enough of this.
Never intended to mix my N's nor my P's and Q's, but thanks for the reminder.
Michelin advice is that ZR rated Michelin's are perfectly safe and can be used on Porsche. The N mark simply indicates what Porsche would prefer us to use it seems.
The ZR speed rating on non 'N' marked tyres is compatible with the published max speed of the car, Porsche included, so no problem exists re safety. Having said that I will fit N rated tyres and respect Porsches judgement.
Nick
Not sure they were answered actually, but enough of this.
Never intended to mix my N's nor my P's and Q's, but thanks for the reminder.
Michelin advice is that ZR rated Michelin's are perfectly safe and can be used on Porsche. The N mark simply indicates what Porsche would prefer us to use it seems.
The ZR speed rating on non 'N' marked tyres is compatible with the published max speed of the car, Porsche included, so no problem exists re safety. Having said that I will fit N rated tyres and respect Porsches judgement.
Nick
Melv said:
Setch -cld I humbly suggest you read the posts in full? Then your q's will be answered..... 
And watch my lips:
DON'T MIX N-RATINGS!!!
Mel
>> Edited by Melv on Friday 11th February 14:02
Luvverly, Mel ! Is it true you are running the next training seminar for potential Register Secretaries ??
cheers, Maurice
Hmmm was talking to local tyre dealer a few weeks ago cos I am gonna change tyres soon. According to him and his tyre distributor the N rating is nothing to do with insurance. It is to do with warranty. Porsche test the tyre to ensure it works well with the transmission and then approve it. Any warranty claims on the transmission with non N rated tyres will not be honoured. Provided the car is fited with the correct speed and load rated tyre the insurance company will pay out on crash damage. As the manufacturers do not retest tyres for older models anyway once the original tyre spec is obsolete then you are stuffed. As for insisting on N rated tyres for older vehicles, judging by the N),1 2,3 etc it would appear you are buying a tyre that is approved for the later model anyway. However looking at the literature my tyre dealer had it appears certain N ratings apply to different models so it it is not very clear.
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