N-Rated Tyres

[Guest]

A subject dear to our hearts - N-rated tyres. Is there any merit in buying them? Well, I came across the following comment on Rennlist this morning from Todd Serota (IT lawyer, owner of Tracquest and Rennlist lifetime member):


Subject: RE: NON " N" Rated Tires for 993 C2
From: " Todd Serota" <tserota@adelphia.net>
Date: Mon, 12 May 2003 14:56:17 -0700
X-Message-Number: 20

Hi Don:

Don' t worry about the N " rating," because it' s not a rating at all.
Rather, it' s just a specification. As Jeff Canaday explained, it simply
means that it' s an OEM (original equipment manufacturer) tire provided
by Porsche at some point when the car was originally sold. Porsche uses
all kinds of criteria in choosing OEM tires for its cars including
noise, wear, comfort and perhaps most importantly of all, price. While
Porsche generally puts good tires on its vehicles, they' re never the
best tires from a performance standpoint because of all of the
compromises Porsche has to make. For example, the best tires for dry
performance are R compound tires, and these are not provides OEM by any
manufacturer other than perhaps a specialty manufacturer that is selling
a street legal race car, like Mosler. Even disregarding R compound
tires, though, the best tires on the market currently from a performance
standpoint are BFG G-Force KD' s and Goodyear F1 Supercars, neither of
which is or has ever been offered OEM by Porsche. Further, for quite
some time (and possibly still), one of Porsche' s OEM choices for the 996
was the Conti Sport, which is miserable from a dry performance
standpoint compared even to other Porsche OEM tires like the Pirelli
P-Zero.

If you have N-spec tires and need to replace one, as Jeff also reported,
mixing a non-N-spec tire in might make some or zero difference. I did
it once when I got a flat and needed to buy a tire quickly and noticed
no difference, even on the track driving very hard.

As for you having to sign the waiver, that' s in part a protection
against liability and in part a marketing tool to try to scare you into
buying N-spec tires from the dealer. Porsche would love to force you to
buy N-spec tires from its dealer network by voiding your warranty if you
don' t, but fortunately for us in the U.S., we have something called
antitrust laws to prevent such abusive tactics.

<snipped>

For a long time, I have thought that the N-spec designation was little more than a marketing tool, so I' m glad someone else agrees with me.

ciao,
Richard

 

[Robbiemeister]

Richard,

I have, for some time been trying to find out if there is a difference between N and the others.

The information which seems to cause most consternation is that someone, a long time ago, in a galaxy far far away, posted a report on the internet saying that size for size N rated tyres had a wider tread.

This may be true or not but it seems to have become imbude in folklore, and is trotted out everytime the subject arises.

If we could settle this issue, one way or another, the subject would be much less of a grey area.

 

[944Turbo]

My thoughts,

My non N-spec 225/255 Dunlops are as wide or wider than my N-spec 225/255 Bridgestone S02' s were (although this has a lot to do with the dunlop rim protectors). I believe that the rumour is that N-spec 225 S02' s were wider than non n-spec S02' s but haven' t seen them so can' t confirm or deny (and in any case in my sizes at least, they are being discontinued).

I can see that on the latest cars that have undergone many hours testing with the tyre companies latest technology N-spec may offer some benefits. Though obviously this will still be a compromise to cover a wide range of circumstances / drivers.

However I am not convinced that fitting an older N-spec is better than fitting a tyre of more modern design / compound. Having said that if the suspension is worn then fitting a higher grip tyre might make the car feel worse.

It' s a complicated and subjective area which makes choice very difficult.

Blind tyre comparison checks are the only true way to identify the ideal tyre - but that introduces new problems. Does the location suit a particular brand? Are you running the best pressure? Does the tester have the same driving style as you?
etc. etc. etc.

I guess find some that work for you and stick with them! unfortunately this could be a costly exercise.

I would recommend fitting the same brand / style on each axle and preferably all 4 wheels as this should give you a consistent base to work from.

One other benefit of fitting the latest tyre is that should you damage one in six months a similar replacement or replacements should be available,

Tony

 

[Guest]

This idea of discontinuing tyres, either because they are last years model or a better version has come along is proving to be a real pain, particularly for me at the moment. My current tyres, which are fine for my 16 year old car given my style of driving etc., are now discontinued (on the rear at least), but I only need to replace the fronts at the moment. So, if I change just the fronts, when the rears need it, then I won' t have matching front/rear. So, I have to bite the bullet and buy all four now, of a somewhat unnecessary more modern compound, and throw away some almost reasonable rears.
Still, I knew this when I bought my first 911 (did I really take notice ?), but having rears that wear out a lot faster than the fronts, and tyre makers that to some extent follow fashion (my tyre dealer has refered to some tyres as being ' sexy' ) is my soapbox mither for today.

So there !

 

[Guest]

This idea of discontinuing tyres, either because they are last years model or a better version has come along is proving to be a real pain, particularly for me at the moment

Such is the pace of change!

If it was me, I would just replace the fronts and worry about the rears later. I have mismatched tyres front/rear on my car right now. Some may tell you this is bad, some may try to convince you it is even dangerous - but the truth is that 911s have different wheel and tyre sizes front/rear anyway - not to mention an uneven weight distribution. Different tyres front and rear may change your handling balance a little - maybe even for the better. As long as you have your eyes open to this change in balance and drive accordingly, you have no problem (other than the self-appointed tyre police[]).

Richard

 

[hawkhead]

>>The information which seems to cause most consternation is that someone, a long time ago, in a galaxy far far away, posted a report on the internet saying that size for size N rated tyres had a wider tread.

This may be true or not but it seems to have become imbude in folklore, and is trotted out everytime the subject arises. <<

It is true. When fitting S02' s at Elite at Rainham I was able to compare normal vs N rated S02' s

 

[Guest]

It is true. When fitting S02' s at Elite at Rainham I was able to compare normal vs N rated S02' s

True for SO2s maybe, but this doesn' t make it true for any other N-rated tyre.

Also, lets think about this some more. Is a wider tyre necessarily a benefit? If you have say 8x16 rear rims and are fitting a 225/50 tyre, then yes, because you have enough rim width to stretch out a wider tyre. But then why not just fit a 245/45? And unless you can run a wider front tyre, why do you want a wider rear tyre? Do you want more understeer? If you have a 7x16 rim then arguably it is of no benefit as your rim is too narrow - just like putting a 245/45 on a 7x16, which will perform less well than a 225/50 on said rim. Similarly, putting a bigger tyre on a 6x16 rim is a waste of time as the standard 205/55 is already marginally too wide for a 6 inch rim.

Can we draw a conclusion? It is safe to say that an N-rated tyre will be different from a non-N-rated. However, unless you know in what respects it differs and whether those differences are actually of any benefit to your car, then whether it is worth any extra cash is a complete lottery. Its your wallet, you make up your own mind. Personally, I dislike paying more than I have to and I particularly dislike buying anything that leaves me feeling like I might be a schmuck.

For most things (parts service etc) we pay a Porsche premium or tax - I just don' t think that we need to pay a Porsche tax on our tyres as well. YMMV.

ciao
Richard

 

[Robbiemeister]

ORIGINAL: hawkhead

It is true. When fitting S02' s at Elite at Rainham I was able to compare normal vs N rated S02' s

David

How ya doin' .

I belive I' m right in saying that the info. on your site regarding this mentions Bridgestone Australia and I thought I remembered seeing the self same quote somewhere else on the web. So I always assumed you had quoted the other source. Was this the case? I have since done a search to see where the text shows up but now only your site comes up. This led me to think that the original source must have been Rennlist or something else semi-permanent like that.

Can you shed any futher light?

 

[Robbiemeister]

Richard

This is such a thorny subject and is consuming so much time and energy.

Would it be possible to get some input from Porsche or one of the tyre companies on this? Would you be prepared to make the approach.

It would be nice to get to the " truth"

 

[Guest]

I thought that 1980s 930s ran 7x16 front, and 8x16 rear, with 205/55 and 245/45. This is obviously to cope with the extra power/rear weight, and not to induce understeer (well, maybe some), I would have thought.
I run the same combination on my modified 3.2 carrera, mostly for the same, power, reasons, and partly because the combination fills the arches better; mine gained no more understeer when I changed from 225/50 to the 245/45.

 

[Guest]

This is such a thorny subject and is consuming so much time and energy.

Would it be possible to get some input from Porsche or one of the tyre companies on this? Would you be prepared to make the approach.

It would be nice to get to the " truth"

I don' t think it is a particularly difficult subject. Some people have swallowed the dealer/tyre retailer/Porsche message that you must have n-rated tyres otherwise you will crash and die. Those people who are capable of applying some logic and reasoning to the question have decided that an n-rated tyre is a tyre that Porsche had some input into and which has some characteristics that may differ from other tyres. This may make the tyre more (or less) suitable for your car and your intended purpose.

As stated above, Porsche' s OEM tyres must meet noise, wear, grip, comfort and price criteria (as must any tyre you may choose). It will be a compromise and not necessarily a better one than some other tyre. If your main criteria is grip you will choose R-compound or something like the BFG G-Force KD. If its price you will choose something like Falken, Kumho etc. If its wear (and poor grip) get Avons. If you must have " Porsche approved" and don' t care about price get N-rated.

The thing about n-rating is that it has this magic aura of Porsche approval so therefore it must be better. There is not a whole lot of info on comparative merits of various tyres so we latch on to the whole Porsche approval thing and follow blindly. Tyre manufacturers are aware of this and charge us more. You want to know about tyres go read www.tirerack.com - they even have some real comparisons.

Finally, there were no n-rated tyres when our cars were made so frankly putting them on our cars is somewhat pointless as (even if they have some merits) they were not designed for our cars in the first place. Just choose something that meets your price/performance criteria and if its n-rated so much the better.

ciao
Richard

PS. I have no interest in approaching Porsche or the tyre companies - I spend too much time posting here let alone chasing tyre companies! Others have tried and nobody has received any particularly worthwhile info AFAIK. If I was a tyre co. selling essentially the same product for a premium I wouldn' t give away any info. Would you? For more info on n-rated you can always look at the other Tyre thread on this board. Personally, I think we have enough info to make up our minds.

PPS. John, just saw your post. Yes, 930s ran 7/8x16 and towards the end of the 1980s 7/9x16. As you note, a 930 has more rear weight bias - heavier engine and engine located more rearwards so it needs more rear rubber. Turning to your car, first, a 225/50 and 245/45 are often very similar in section width, nomenclature notwithstanding, so you may have little extra rubber on the rear anyway. Secondly, a 7x16 front will stretch out a 205/55 much more than a 6x16, so, assuming you changed from a 6 to a 7, front grip will increase. Thirdly, a 7x16 also widens the front track, again increasing front grip, turn-in etc. Fourthly, in steady state cornering power does not enter the equation, however, weight does. Corner exit under power is a different story and is usually a power understeer story unless you carry a lot of speed thru the corner. Hope this helps. Before anyone shoots me down, I have used very simplistic terms like " grip" . I am aware that there is much more complex analysis behind these simple terms.

 

[Jamie Summers]

Oi , Bernau ! Enough of the Avon bashing ok ![]

 

[Robbiemeister]

You' ve made your mind up then?

 

[Jamie Summers]

I' m going to go for the Toyo Proxes T1-S - just need to see if I can scrub a bit more tread off the damn Avons to really justify it. Look out for me, I' ll be the one going round roundabouts sideways []

Jamie

 

[Robbiemeister]

What size/type are the Avons Jamie?

 

[Guest]

Oi , Bernau ! Enough of the Avon bashing ok !

Toyos T1S will be quite an improvement. They are top of my list when I am next in the market.

Richard
(Savaged by an Avon when just a child and emotionally scarred [][][][])

 

[Jamie Summers]

Robbie,
They' re ZZ1' s 205/55 and 225/50 16' ' and they' re not much good ! They seem to be a brutally hard compound that just won' t wear down. Quite fun for donuts and power slides but that' s about it !

Richard,
I think I posted this a while ago, but www.mytyres.co.uk are unbelievably cheap for pretty much anything as far as I can see - you may even have managed to persuade me to forget about going for the N-rated ones []

Jamie

 

[Robbiemeister]

Jamie

Wrong type and size otherwise I might have taken them off your hands.

I was " forced" into ZZ3 for the front of my car recently when the fitted S01' s decided to reveal the carcase during a track day.

I wasn' t actually forced it' s just that the tyre place local to Castle Combe didn' t have anything I knew of at a price I wanted to spend so I just took the cheapest.

But thats my philosophy with tyres. If they are made of rubber and keep the air in they are fine for the road. If they don' t wear down too quick and or they are cheap theyre fine for the track. As somone once said the less they grip the slower you' ll be going when you go off!

Cheers

 

[hawkhead]

The original quote came from an email on Porschefans. When I came to buy tyres I knew I wanted either Eagle F1' s or S02' s

Elite had the N rated S02' s . There was no price difference and I was able to confirm the size difference

Under 400 quid all in for 2 x 225/50 and 2 x 245/45 (16Inch)

The comment about understeer is tru but many other other things (e.g. rear a/r bar stiffness) can have a much bigger effect

 

[Guest]

As somone once said the less they grip the slower you' ll be going when you go off!

Or conversely, the less they grip, the less you will slow down when you spin off and hit something []

I do however agree with you. A good consistent road tyre is perfect for track days (when you first start doing them anyway) but soon the speed bug will bite. A set of R-compounds seems very attractive when you start mixing it up with " faster" cars - like when you find a 996 Turbo holding you up in the corners [].

ciao
Richard