NFx Rating: Myth or Truth?

[tchavei]

N-spec tire threads are almost as bad as oil threads, especially in forums like Rennlist, it’s brutal. It’s good to see a civilized discussion.

I’m not sure I buy the trimmed description as I’ve been running N-spec tires for decades and never noticed. However, I’ve had many a tire that listed to one side from all manufacturers when standing unmounted, regardless of manufacturers spec. It’s usually caused by sidewall construction or tread design (more large blocks or a “slick” style design means they’re more “rubber” and more weight on that side of the tread).

If a tire has a specific tread design for the inner and outer contact patch or a different inside vs. outside sidewall construction it will have “OUTSIDE” printed on the sidewall. That has nothing to do with directional tread. Tires that have directional tread will have an arrow on the sidewall indicating the direction of travel. A tire can’t have both unless they have different tires for left and right. That is extremely rare, I haven’t seen that since the 90’s.

Yes, I agree. However bear in mind the tyre guy was very certain of his claims (he still could be wrong though)

I also considered he could have a higher profit margin from a specific brand but he didn't insist on any of them so it felt genuine on his part. I mean, we have Contis, Goodyear and Michelin in NF0. He didn't flinch on any of them. I also know that he personally loves Bridgestone (so do I. Probably influenced by him through many years of usage). Bridgestone doesn't do 305 in 21'' so maybe that's why he didn't mentioned those.

In the end I had him order the asymmetric 5 NF0 just because of warranty stuff.

I might be wrong but I felt it would be easier to counter a warranty denial based only on the rims (exactly same specs as OEM in terms of size, width, etc) then rims + non NF0 tires.

Always hoping the best but preparing for the worst.

Maybe hankook will get those iON porsche approved or I'll have to wait 3 years for the warranty to expire.

Sponsored

 

[mjw930]

Absolutely, he could have inside info and I’ve seen lots of shaved tires over the years. Regardless, you stick with N-spec and you will never go wrong.

And No, your car won’t explode if you don’t use N-spec

 

[TDinDC]

I know this is a bit stale, but I just saw this brief article that provided interesting information on why there might be a difference between N spec and other specs: specialized rubber compounds based on precise needs of individual cars.

Now, I have never limited myself to N spec tires but do choose them if they happen to match up with my needs. Maybe I will consider a stronger preference (but again not likely to refuse to use a non N spec tire because I will likely never push any tire of the street hard enough to notice the difference -- apart from perhaps an emergency procedure where, admittedly, I would want every advantage).

https://apple.news/AkRMVxlm3TPWIqUv16b6CDg

 

[ciaranob]

Very late add her but only just seen this post .

I have a set of Pirelli NF0 tires in my garage ready to replace my factory set - I can take a rear/front pair down from my rack and see if I can see this 'tilt' due to shaving - will report back with pics later.

 

[ciaranob]

I have a set of Pirelli NF0 tires in my garage ready to replace my factory set - I can take a rear/front pair down from my rack and see if I can see this 'tilt' due to shaving - will report back with pics later.

So - if its there its pretty damn subtle and this seriously rough look and guide not to be trusted too much as done in a hurry That said I think I am seeing the subtlest of angle differences on the inside of both the rear and front of my unused/unmounted, new Pirelli P-Zero NF0 tires!

Again a very quick and dirty test/look and I really need to do a proper/more scientific(!) job later - but you have me interested now !

Can't really tell squat from this view but when I stood back I could swear I saw subtle lean as you mentioned. So next, put the level on top....

EDIT _ PLEASE be aware that I know the point at which we are looking at 'drop-off/angle change' on outside and inside of each tire is NOT the exact same location (distance in from the edge) across the curvature of the top tire due to thread design being different either side - this alone my account for what I am seeing but TBH, not sure that the is actually so!

Spirit is level so I will show a zoom in on both LHS and RHS - look at the slightly wider gap (angle/drop off) for the inside of each tire where the level separates from the tire:


Inside mount of rear tire - clear gap under level:

Outside (visible side when mounted) view of rear tire - tire actually touches level before splitting off:

Inner side front tire (if mounted) - same gap where level separates from tire:

Outer (visible when mounted) side of front tire - not as pronounced perhaps as on rear but actually partly a bad photo angle - the I took it it was again apparent that the drop off/angle was larger than on teh inside of the tire:

So possibly what that tech was telling you was fairly accurate - and as far as softness goes we all know how soft theses Pirelli's are (wasn't a planned choice to replace with original OEM but different story!).

 

[tchavei]

So - if its there its pretty damn subtle and this seriously rough look and guide not to be trusted too much as done in a hurry That said I think I am seeing the subtlest of angle differences on the inside of both the rear and front of my unused/unmounted, new Pirelli P-Zero NF0 tires!

Again a very quick and dirty test/look and I really need to do a proper/more scientific(!) job later - but you have me interested now !

Can't really tell squat from this view but when I stood back I could swear I saw subtle lean as you mentioned. So next, put the level on top....

EDIT _ PLEASE be aware that I know the point at which we are looking at 'drop-off/angle change' on outside and inside of each tire is NOT the exact same location (distance in from the edge) across the curvature of the top tire due to thread design being different either side - this alone my account for what I am seeing but TBH, not sure that the is actually so!

Spirit is level so I will show a zoom in on both LHS and RHS - look at the slightly wider gap (angle/drop off) for the inside of each tire where the level separates from the tire:


Inside mount of rear tire - clear gap under level:

Outside (visible side when mounted) view of rear tire - tire actually touches level before splitting off:

Inner side front tire (if mounted) - same gap where level separates from tire:

Outer (visible when mounted) side of front tire - not as pronounced perhaps as on rear but actually partly a bad photo angle - the I took it it was again apparent that the drop off/angle was larger than on teh inside of the tire:

So possibly what that tech was telling you was fairly accurate - and as far as softness goes we all know how soft theses Pirelli's are (wasn't a planned choice to replace with original OEM but different story!).

Thank you very much for your investigation.

Yeah, I saw the same tilt at the shop (it's subtle indeed. Not like 45 degree tilted lol) but after the comments on this thread I kinda dismissed the experience. Good to know I'm not crazy (well maybe to a lesser degree only).

My assymetric 5 still going strong after 7000km (god, I'm putting more km into this beauty than my old Mercedes diesel workhorse).

I noticed pressure makes a big difference in feel. For some reason my pcm "thinks" my front should be at 2.4 bar and my rear at 2.6 but steering feels more mushy then when they're all at 2.6-2.7. I prefer the crisp feeling and I'm guilty of in the past (and other cars) rarely checking pressures which invariably ended with me chewing the outer edge of my tires. Trying to be much more attentive with this one without looking too car obsessed.

 

[whitex]

So - if its there its pretty damn subtle and this seriously rough look and guide not to be trusted too much as done in a hurry That said I think I am seeing the subtlest of angle differences on the inside of both the rear and front of my unused/unmounted, new Pirelli P-Zero NF0 tires!

Again a very quick and dirty test/look and I really need to do a proper/more scientific(!) job later - but you have me interested now !

Can't really tell squat from this view but when I stood back I could swear I saw subtle lean as you mentioned. So next, put the level on top....

EDIT _ PLEASE be aware that I know the point at which we are looking at 'drop-off/angle change' on outside and inside of each tire is NOT the exact same location (distance in from the edge) across the curvature of the top tire due to thread design being different either side - this alone my account for what I am seeing but TBH, not sure that the is actually so!

Spirit is level so I will show a zoom in on both LHS and RHS - look at the slightly wider gap (angle/drop off) for the inside of each tire where the level separates from the tire:


Inside mount of rear tire - clear gap under level:

Outside (visible side when mounted) view of rear tire - tire actually touches level before splitting off:

Inner side front tire (if mounted) - same gap where level separates from tire:

Outer (visible when mounted) side of front tire - not as pronounced perhaps as on rear but actually partly a bad photo angle - the I took it it was again apparent that the drop off/angle was larger than on teh inside of the tire:

So possibly what that tech was telling you was fairly accurate - and as far as softness goes we all know how soft theses Pirelli's are (wasn't a planned choice to replace with original OEM but different story!).

Are the left and right tires tilting in the opposite directions when both next to each other with the same direction of rotation? If so, are they labeled, or do you have 50:50 chance of getting it right or wrong?

Seriously, unless they are in fact labeled left/right and direction of rotations, they cannot be tilting. If unlabeled, how would you prevent the dealer from selling you two left tires for example?

 

[bsclywilly]

What you're seeing is just the weight imbalance from inside of the tread to the outside and the fact that the tire doesn't sit perfectly flat so it's going to lean towards the side that has less tread void and is heavier. There's no such thing as cone shaped tires, at least none that go fast in a straight line.

 

[gtm]

Again a very quick and dirty test/look and I really need to do a proper/more scientific(!) job later - but you have me interested now !

Interesting "test" but a tire must be mounted and properly inflated to draw any conclusions. The distance from the inside bead to the outside bead on an uninflated tire is smaller than the rim width. Mounting and inflating moves the tire beads farther apart and changes the sidewall and tread profile. Shipping and storage can frequently do strange things to the shape of a tire. I ran a shop for many years and you can't believe how tires are treated. Once you have the tires mounted repeat your test.

I'm not saying the NFO tires are or aren't trimmed/shaved/tapered (although I've never known this to be a real thing in 25 years selling tires), but you can't draw any conclusions from an unmounted tire.

 

[gtm]

Are the left and right tires tilting in the opposite directions when both next to each other with the same direction of rotation? If so, are they labeled, or do you have 50:50 chance of getting it right or wrong?

Seriously, unless they are in fact labeled left/right and direction of rotations, they cannot be tilting. If unlabeled, how would you prevent the dealer from selling you two left tires for example?

Most performance tires have different tread patterns inside versus outside (the pattern is asymmetric) and the tires are labeled on the sidewalls to prevent being mounted backwards. Directional tires have the same tread pattern inside and outside. There are very very few tires that are both directional and asymmetric. Those would require the tires to be marked left and right as well as inside/outside. My Lotus has different sizes front and rear. 4 different part numbers when I put on a set of Yokohama tires. Porsche NFO tires are asymmetric but not directional.

 

[Bao1303]

Seems strange. If this was true and the tyres designed with a camber it should apply to winter tires as well. Running studded nordic tyres and no such thing as NO approval for those. No hassle from Porsche regarding that. Would assume that using rated tyres has to do with all-out-on-the-limit performance driving only. Also a good way for Porsche to source those magic tires and add some Porsche tax on top, same as BMW with their stars

 

[mystermykee]

From what I understand, it's not about getting a tire N(F) approval, but rather the tire manufacturer working in conjunction with Porsche to develop/tweak a tire for a specific application.

Majority of the time, we're not driving near the limit to notice the difference (some are oblivious to how their car drives). I like having the piece of mind that I have a tire specifically tweaked for the Taycan (noise, lower rolling resistance etc). You never know when you just might need that stiffer sidewall.

 

[Vercingetorix]

From what I understand, it's not about getting a tire N(F) approval, but rather the tire manufacturer working in conjunction with Porsche to develop/tweak a tire for a specific application.

Majority of the time, we're not driving near the limit to notice the difference (some are oblivious to how their car drives). I like having the piece of mind that I have a tire specifically tweaked for the Taycan (noise, lower rolling resistance etc). You never know when you just might need that stiffer sidewall.

The issue is you have no idea what they are tweaking. Trading rolling resistance for wet traction, who knows? At least with non NF0 you can find comparisons between different tires that are all non NF0. I have no issues with NF0, but guys running rear tires optimized for Mercedes and fronts not optimized for anything are maybe running a compromised set up. Again who knows without testing.

 

[Avantgarde]

Guess nobody wanted to bite into this subject.

I'm most likely going for the Goodyear Eagle F1 Asymmetric 5 NF0

Going to have enough hell with Porsche in case of a warranty issue by having aftermarket rims, don't need even more trouble by not having NF0 rated tyres.

I guess it is what it is.

Maybe in a few years the Hankook iON will get the Porsche seal of approval.

Cheers.

Hi may I ask if you end up getting these tires? Are you happy with them? Noise level is the most important criteria for me. Appreciate any feedback you may have on that.

Also Good year website classified Assym. 5s as "M+S" all season tiers. But other websites call them "summer performance". Are there multiple versions?

 

[tchavei]

Hi may I ask if you end up getting these tires? Are you happy with them? Noise level is the most important criteria for me. Appreciate any feedback you may have on that.

Also Good year website classified Assym. 5s as "M+S" all season tiers. But other websites call them "summer performance". Are there multiple versions?

The goodyears are good enough. I'm on my second set. First set lasted around 28k Km (would have gotten to 30k easily) because I had a flat which was repaired but I had a long trip ahead of me and was scared there could be an issue.

There's also version 5 NF1 but when I tried to get those, only NF0 where available. Supplier said "They pulled the NF1 after they started melting on italian roads in the summer"... if that's true or not, I have no idea. Wouldn't be surprised though.

Regarding noise... nothing extraordinary for my ears. Seem quite quiet.

Yes, they are summer tires... never seen M+S... they would be useless here in Portugal anyway.

Cheers

Sponsored