"N" rating on tires

[JGibb62]

Tire question on my '84 911 M491 (FTL)
Tire rack has Michelin pilot a/s 3 and exalto. a/s is all season which i prefer for winter driving - dry conditions. exalto is summer only but has the 'N" rating - porsche approved. A/S 3 does not have the N rating. I don't plan on driving the car at or near its top speed anytime soon. Does "N" rating matter?

[sp_cs]

The N rating isn't a speed rating in the same way W, Y and Z are

[javadog]

Porsche often has a tire manufacturer build a version of one of their tires that might differ in some way from the non-N version of the same tire. This comes as a result of testing that Porsche has done with the tire on their cars. There's no telling what the differences might be, but Porsche prefers "their" version, for one reason or another.

JR

[Bill Verburg]

Originally Posted by javadog

Porsche often has a tire manufacturer build a version of one of their tires that might differ in some way from the non-N version of the same tire. This comes as a result of testing that Porsche has done with the tire on their cars. There's no telling what the differences might be, but Porsche prefers "their" version, for one reason or another.

JR

key word is 'might', the N rating just means that Porsche has tested the tire for compatibility w/ their expectations, The tire construction may or may not have been modified in some way from the base spec to accommodate Porsche.

The N rating can have multiple Iterations ie N1, N2, N3 etc.

Personally I don't worry about N ratings.

[wildthing]

I recently found an N-rated version of the Bridgestones I had, and they happen to be $5 cheaper at that time. That would've been the only reason I would buy them over the regular one. But it wasn't time to change yet...

[McLaren-TAG]

N rating does not in any way mean that they're better for our cars. Especially if you car is modified. It is simply a rating for the masses which may or my not have any bearing on you, your car or the way you drive.

[techman1]

I recall a recent auto show (Possibly Motorweek) that discussed the tires used on 80's sports cars, Ferrari and Porsche were mentioned. They pointed out the tires used on new Honda and Hyundai cars have better spec's !!

That being said, I wonder if a 245 (or any other rear tire) that is N spec has a thicker sidewall for rear engine weight versus non N spec? Regardless, I will look at recommendations and tire specs first, price second, N spec last.

[Cajundaddy]

Originally Posted by techman1

I recall a recent auto show (Possibly Motorweek) that discussed the tires used on 80's sports cars, Ferrari and Porsche were mentioned. They pointed out the tires used on new Honda and Hyundai cars have better spec's !!

That being said, I wonder if a 245 (or any other rear tire) that is N spec has a thicker sidewall for rear engine weight versus non N spec? Regardless, I will look at recommendations and tire specs first, price second, N spec last.

No difference in sidewall, just Porsche tested, Porsche approved, and usually 2x the price.

[javadog]

Originally Posted by McLaren-TAG

N rating does not in any way mean that they're better for our cars. Especially if you car is modified. It is simply a rating for the masses which may or my not have any bearing on you, your car or the way you drive.

Porsche might disagree with you. They have been involved in tire testing for a lot longer than people realize at their Weissach center. Apart from the driving and skid pad tests they have done since the 1950's, they installed some special test gear several decades ago that allow them to test a variety of tire characteristics. As far as I know, they were the first to do so, apart from tire companies. Just the other day, I was looking at graphs of tire tests they did of 7 tires back in the 1970's. They looked at 7 different tires that were available for their cars, and measured the grip, slip angles, cornering stiffness and other things. You can add to that driving tests done on their skid pads, test track and local autobahns. They burn up a lot of tires.

They also do the same thing with winter tires. It's not well known here, but they publish lists of their suggested choice for winter tires. In the past, it was done on an annual basis, although I don't know what they are doing currently.

JR

[McLaren-TAG]

Originally Posted by javadog

Porsche might disagree with you. They have been involved in tire testing for a lot longer than people realize at their Weissach center. Apart from the driving and skid pad tests they have done since the 1950's, they installed some special test gear several decades ago that allow them to test a variety of tire characteristics. As far as I know, they were the first to do so, apart from tire companies. Just the other day, I was looking at graphs of tire tests they did of 7 tires back in the 1970's. They looked at 7 different tires that were available for their cars, and measured the grip, slip angles, cornering stiffness and other things. You can add to that driving tests done on their skid pads, test track and local autobahns. They burn up a lot of tires.

They also do the same thing with winter tires. It's not well known here, but they publish lists of their suggested choice for winter tires. In the past, it was done on an annual basis, although I don't know what they are doing currently.

JR

And everything you say is true; I've been to a couple of PCA hosted TechTactics session where they've brought tire engineers to talk specifically about N spec tires and they are indeed different even than similar looking or same tire without the N spec.

What I say however is that none of it matters if like most of the people here they've upgraded the suspension, sway bars, bushings, torsion bars etc etc etc...

Porsche N spec is for their cars as they come out of the factory not for cars that have been modified considerably as a lot of the guys on this site have done.

[javadog]

My take on it is that most people in the world can't extract the last 20% of the car's, or their tire's capabilities, so it's largely a moot point anyway.

Nothing against people that autocross or track their cars but there's a lot more to it than lateral grip, which is usually the main characteristic most people use to judge a tire.

JR

[Jeff Alton]

If you are looking for an N rated tire for your 25+ year old Porsche, you are wasting your time. When Porsche tests the latest tire and allows it to be marketed as N, they didn't test it on a 911 SC...

Cheers

[javadog]

Originally Posted by Jeff Alton

If you are looking for an N rated tire for your 25+ year old Porsche, you are wasting your time. When Porsche tests the latest tire and allows it to be marketed as N, they didn't test it on a 911 SC...

Cheers

And, that would be wrong. I can't tell you when they tested them, or on what, exactly (a red one, a blue one?), but here's what they have to say about tire testing:

"In order to recommend tires to drivers of Porsche Classic cars, Porsche also publishes lists of approved tires for vintage cars and recent classics at regular intervals. For this purpose, more than 150 different sets of tires are tested in a wide variety of disciplines, on the relevant original vehicles."

They are happy to supply a list of both summer and winter tires, for any model they built, starting with the 356. Here's where you can view the current air-cooled 911 list:

Porsche Tire approvals - Porsche Cars North America

I guess we are fortunate that they have a few hundred examples of their older cars laying around, for ****s and giggles.

JR

[javadog]

Here's a little more information on the N branding, for those of you that think it's not something that is actively tested. From Porsche:

"Porsche N-marked tires primarily differ from other tires due to their special design. They provide excellent driving stability – and maximum driving pleasure. During development, the tire geometry and rubber composition in particular, are tailored to Porsche vehicles. And this applies to all Porsche approved tires, be they all-season, summer, winter or high-performance tires.

All the tires available from your Porsche Service Advisor at your authorized Porsche dealer have been thoroughly tested and approved by Porsche. This is distinguishable by the N-marking which is always specified in the tire's technical data, and abbreviated to N0, N1, N2, N3, N4, N5 and N6. The marking refers to the technical status at the time approval was obtained, and progressively increases with each significant evolution of the tire. A Porsche-approved tire ensures that your vehicle retains its original driving performance and safety margins, even after being fitted with a new replacement tire. There are many reasons for this. Or 33 to be precise.

Porsche N-marked tires primarily differ from other tires in terms of their geometry, rubber composition and testing method, which includes a total of 33 important criteria. These consist of 12 objective outdoor criteria, such as wet and dry braking performance and service life. There are also 16 objective test rig criteria, including rolling resistance and performance at high speed. And five subjective outdoor criteria, such as handling and driving comfort, are also considered. The tangible result: driving pleasure and safety."

I'm not saying that you should only consider N branded tires, I'm just pointing out that there is a little more to it than it first might appear.

JR

[Jeff Alton]

And notice how many do not carry the N spec... The N spec was not achieved by testing it on the older cars. Yes, an N spec tire may make the list, but a few non N spec tires are on the list as well.

[McLaren-TAG]

Which as to the OP's initial comment, he clearly would not benefit from an N rating, expecially since he's looking for an all season tire and states he won't be pushing hard.

[javadog]

Originally Posted by Jeff Alton

And notice how many do not carry the N spec... The N spec was not achieved by testing it on the older cars. Yes, an N spec tire may make the list, but a few non N spec tires are on the list as well.

If you read the air-cooled 911 list, exactly one summer tire, the Michelin XAS in 165 HR 15 as fitted to a 4.5 or 5.5Jx15 wheel, was not an N-spec tire. Just one. All of the rest were, from N0 to N3.

And you don't think they tested those on an air-cooled 911, is spite of them stating that that's exactly what they did? You figure they tested that 165 HR 15 Michelin on a 4.5x15 wheel while it was mounted on a Boxster? Maybe a Cayman?

Come on...

The winter tires are basically snow tires, since that is what "winter tire" means to a a German, so that list will be less helpful to us.

JR

[javadog]

Originally Posted by McLaren-TAG

Which as to the OP's initial comment, he clearly would not benefit from an N rating, expecially since he's looking for an all season tire and states he won't be pushing hard.

Yeah, I got that, which is why I said this:

Originally Posted by javadog

My take on it is that most people in the world can't extract the last 20% of the car's, or their tire's capabilities, so it's largely a moot point anyway.

I'm just pointing out a few facts, for those that might read this thread and want to learn something, to counter the 'it's all horse****" claims from people that have no idea of any of the facts. This is an educational forum, I'm in favor of people learning about something and making their own mind up about it. I think people really have no idea about half of what goes on back in Germany.

JR

[Jeff Alton]

Javadog,

You may be correct. A more detailed review of the lists suggests that

But I have a hard time believing the tire was made specifically for Porsche. I just can't see justifying the expense of making a specific tire just for porsche in a size where they might sell a few hundred globally each year.

Of note the only "approved" tires are from manufactures who are/were OE to Porsche. I would suspect there is a marketing deal/angle buried in there somewhere...

When one takes a look at the recommendations it is hard not to be skeptical. They suggest the same tires for a Boxster and a 996. Both have different needs from an alignment perspective. They recommend the same tire for a 928S as they do for a 986 (same size).

They recommend the Michelin PS2 but not the PSS, even though the PS2 has a shoulder that gets eaten away with spirited driving at stock alignment settings...

So yes, I was wrong that they don't test the tires on the older cars, though what that testing amounts to is still undetermined. But I still think one is wasting their time looking for a N spec tire.

[javadog]

Having a tire made for a specific vehicle happens all the time, not just with Porsche. There are even specific sizes, made for just one vehicle. Nothing new, been that way for 30+ years.

There is no doubt that Porsche works with their OEM tire suppliers, more than others. That doesn't stop them from looking at others when they are evaluating a tire. When they initially developed the initial 50-series Pirelli P7 applications in the mid-1970's for the 930 they tested every other tire available at the time that was suitable for use on that car.

They have always tested tires on the road and on the track. A long time ago, they purchased some fairly exotic tire testing equipment. For example, there is a large rotating drum that they can run a tire in, where they can load it in several directions, run it at different angles, run it at varying loads and at speeds up to the top speed that the tire will see in service. Probably half of their testing is done in rigs like that. The rest is done on their test tracks and skid pads. They also do some testing on public roads, at tracks like the Nurburgring and Nardo, etc.

JR