Do I need to replace both front tyres due to a puncture?
Discussion
ilduce said:
Ha! look at this bit:
"The “N” Marking means that the tyres compound and pattern stays the exactly the same as the day it was tested by Porsche as tyre companies normally make small alterations to the compound or tread pattern etc, with an “N” marked tyre no alterations are permitted as alterations could have a negative effect on the Porsche’s handling."
Explain to me how over 90k miles:
N1's did 12-14k miles
n2's did 12-14k miles
n3's did 6-7k miles
same driving route. same MPG. same driving style.
If you read the rest of the article, you'll see that it says there's significant differences between N1, N2 and N3. It goes as far as saying you shouldn't mix N marked tyres as they can be so different. As you're experience as clearly shown...."The “N” Marking means that the tyres compound and pattern stays the exactly the same as the day it was tested by Porsche as tyre companies normally make small alterations to the compound or tread pattern etc, with an “N” marked tyre no alterations are permitted as alterations could have a negative effect on the Porsche’s handling."
Explain to me how over 90k miles:
N1's did 12-14k miles
n2's did 12-14k miles
n3's did 6-7k miles
same driving route. same MPG. same driving style.
I wouldn't want you to miss this....
Seriously?
Where are these part numbers held?
Orangecurry said:
RacerMike said:
Orangecurry said:
How can a single tyre be optimised for the back of a Boxster and the back of a 996?
Or the back of a Cayman and the front of a CGT?
You'll find that it isn't! OEM spec from someone like Blackcircles will be closer than the a non N rated version, however, the same tyre, same 'spec' (i.e. N1) can also then have a different part number which means it is different, but without any identifiable markings apart from the sticker. Obviously, if you order your tyres from a Porsche dealer, they order the relevant part number which means you get the correct model spec of the same rating.Or the back of a Cayman and the front of a CGT?
Where are these part numbers held?
PorscheGT4 said:
RacerMike said:
....that won't have the original attributes designed to work with the car! If you want a trackday tyre, go for it, but if you want to maintain the original chassis balance, ride comfort, turn in response, wear, longitudinal grip, water clearance, slip behavior on high Mu, slip behavior on medium Mu, heat resistance, steering feel, braking feel, traction control performance, ABS performance, Stability Control performance, PASM response, fuel economy etc. etc. then you have to get the N rated tyre as specced for the car.
.
SS out classes any N spec tyre in all those area's ;-).
1) Even the wet grip and noise markings of the approved tyres for the 981 differ between the approved N spec tyres from the different manufacturers - so there isn't a Porsche "standard" for how the car should behave.
2) I've never seen a tyre which out-classes rival manufactures equivalents in ALL areas mentioned in any tyre test - accepting that it might in some.
3) I personally have never seen an independent Porsche N spec tyre comparison (is there one?), let alone one comparing N and non-N tyres. So I have no real data to work on - which is (or will be) frustrating when I am due for new tyres.
So, while the car is under warranty I'll feel obliged to stick with N spec tyres, even though another tyre might better meet my personal priorities, and any change (to another N spec tyre) will have to be taken rather blind, based on possibly unreliable non-N tyre comparisons and anecdotal information.
RacerMike said:
ilduce said:
Ha! look at this bit:
"The “N” Marking means that the tyres compound and pattern stays the exactly the same as the day it was tested by Porsche as tyre companies normally make small alterations to the compound or tread pattern etc, with an “N” marked tyre no alterations are permitted as alterations could have a negative effect on the Porsche’s handling."
Explain to me how over 90k miles:
N1's did 12-14k miles
n2's did 12-14k miles
n3's did 6-7k miles
same driving route. same MPG. same driving style.
If you read the rest of the article, you'll see that it says there's significant differences between N1, N2 and N3. It goes as far as saying you shouldn't mix N marked tyres as they can be so different. As you're experience as clearly shown...."The “N” Marking means that the tyres compound and pattern stays the exactly the same as the day it was tested by Porsche as tyre companies normally make small alterations to the compound or tread pattern etc, with an “N” marked tyre no alterations are permitted as alterations could have a negative effect on the Porsche’s handling."
Explain to me how over 90k miles:
N1's did 12-14k miles
n2's did 12-14k miles
n3's did 6-7k miles
same driving route. same MPG. same driving style.
My experience shows that it doesn't, so it's hard to take it seriously.
Wow - who knew a simple question could end up in so much heated debate?! It makes for interesting reading though.
For what it's worth, thanks to the early advice on here, I decided to replace both fronts via my local place, they order direct from the manufacturer so will be as new as you can get. I decided on the N rated OEM fits (cue more arguing or tutting or tutting on here!).
Amazingly though when they had a look at the tyre in question and took the screw out, the little b
d hadn't made it all the way through, so the fronts live to fight another day!! 
For what it's worth, thanks to the early advice on here, I decided to replace both fronts via my local place, they order direct from the manufacturer so will be as new as you can get. I decided on the N rated OEM fits (cue more arguing or tutting or tutting on here!).
Amazingly though when they had a look at the tyre in question and took the screw out, the little b
d hadn't made it all the way through, so the fronts live to fight another day!! ilduce said:
The article says the compound stays the same.
My experience shows that it doesn't, so it's hard to take it seriously.
Construction hugely effects wear. Changes in belt or sidewall construction alter the temperature profile across the tyre, so a softer construction can cause higher wear rates on a car where the geometry was designed for a stiffer tyre.My experience shows that it doesn't, so it's hard to take it seriously.
Orangecurry said:
It always ends up in a bunfight 
But I'm awaiting RacerMike's reply on his statement that each N-rated tyre for each different Model of Porsche has a different Porsche part number as well, which your tyre-specialist doesn't have access to.
Apparently.
Part numbers are assigned by OEMs to tyres, wheels and wheel and tyre assemblies for each vehicle. During build, assemblies, rather than separate tyres and wheels are delivered to the production line from one of the many automotive supply companies who do all the wheel and tyre assembly off site.But I'm awaiting RacerMike's reply on his statement that each N-rated tyre for each different Model of Porsche has a different Porsche part number as well, which your tyre-specialist doesn't have access to.
Apparently.
A Michelin on one model will usually have a different part number to the 'same' Michelin on another model to allow identification of different specs. When the dealer goes to order parts for a car, they enter the VIN which will mean the correct tyre is ordered. In development, we have to specify tyres by part number rather than make and model to make sure we get the correct compound and construction for the correct tyre. It's not possible to order 'a 20" Goodyear'. You have to order 1 off ABCD-1234-567....
RacerMike said:
ilduce said:
The article says the compound stays the same.
My experience shows that it doesn't, so it's hard to take it seriously.
Construction hugely effects wear. Changes in belt or sidewall construction alter the temperature profile across the tyre, so a softer construction can cause higher wear rates on a car where the geometry was designed for a stiffer tyre.My experience shows that it doesn't, so it's hard to take it seriously.
RacerMike said:
Part numbers are assigned by OEMs to tyres, wheels and wheel and tyre assemblies for each vehicle. During build, assemblies, rather than separate tyres and wheels are delivered to the production line from one of the many automotive supply companies who do all the wheel and tyre assembly off site.
A Michelin on one model will usually have a different part number to the 'same' Michelin on another model to allow identification of different specs. When the dealer goes to order parts for a car, they enter the VIN which will mean the correct tyre is ordered. In development, we have to specify tyres by part number rather than make and model to make sure we get the correct compound and construction for the correct tyre. It's not possible to order 'a 20" Goodyear'. You have to order 1 off ABCD-1234-567....
But that doesn't mean the Michelin tyre has a Porsche part number at Michelin.A Michelin on one model will usually have a different part number to the 'same' Michelin on another model to allow identification of different specs. When the dealer goes to order parts for a car, they enter the VIN which will mean the correct tyre is ordered. In development, we have to specify tyres by part number rather than make and model to make sure we get the correct compound and construction for the correct tyre. It's not possible to order 'a 20" Goodyear'. You have to order 1 off ABCD-1234-567....
I think you are suggesting that there are (at least) three DIFFERENT Michelin PS2 N3 in 265/35/18 ? One for the Boxster, the 993 and the 996? And the difference is denoted on the sticker and it can only be ordered by an OPC?
I think we'd better ask the Michelin man
You keep saying this. Can you actually give us any evidence, because I've never heard a sniff of anyone else ever suggesting that there are (for example) three different Michelin 265/35/18 N3 tyres, each different for the 993, 986 and 996.
Not even the guy from Michelin.
And as someone else pointed out, the N-rated Pirelli, Bridgestone and Michelin in that size cannot possibly give the same long list of characteristics that you listed as being so critical.
SO it's all nonsense anyway
Not even the guy from Michelin.
And as someone else pointed out, the N-rated Pirelli, Bridgestone and Michelin in that size cannot possibly give the same long list of characteristics that you listed as being so critical.
SO it's all nonsense anyway
RacerMike said:
Orangecurry said:
But that doesn't mean the Michelin tyre has a Porsche part number at Michelin.
Yes it does. There are literally hundreds of different compounds/constructions of the same tyre from the tyre manufacturers.Are you saying that unless you order your tyres from an OPC you could possibly get tyres for the wrong Porsche?
That's bullsh'it on par with the OPC telling me that an identically rated non-Porsche battery could do damage to my car.
Edited by ilduce on Friday 27th March 13:51
Orangecurry said:
And as someone else pointed out, the N-rated Pirelli, Bridgestone and Michelin in that size cannot possibly give the same long list of characteristics that you listed as being so critical.
Eh? Why is that? The whole process of assessment, development and sign off is to achieve a set list of characteristics in each tyre. This is precisely why there are so many different specifications of the same tyre. The targets set by Porsche will be different to those set by Audi, which means they have to adjust elements of the tyre design and chemistry. All the different manufacturers have to change they're tyre to meet the targets set by Porsche. The aim is for them to all offer as similar as possible behaviour.Surely the picture posted a page or so back of the two Cup tyres next to each other is evidence to this.
RacerMike said:
Eh? Why is that? The whole process of assessment, development and sign off is to achieve a set list of characteristics in each tyre. This is precisely why there are so many different specifications of the same tyre. The targets set by Porsche will be different to those set by Audi, which means they have to adjust elements of the tyre design and chemistry. All the different manufacturers have to change they're tyre to meet the targets set by Porsche. The aim is for them to all offer as similar as possible behaviour.
Surely the picture posted a page or so back of the two Cup tyres next to each other is evidence to this.
Yes but the fact that for my Cayman an N0 rated Goodyear F1 or Pirelli Zero rear is rated A for wet grip and a N0 Michelin Cup 2 is rated C suggests that there is still very significant difference in characteristics. Surely the picture posted a page or so back of the two Cup tyres next to each other is evidence to this.
bcr5784 said:
Yes but the fact that for my Cayman an N0 rated Goodyear F1 or Pirelli Zero rear is rated A for wet grip and a N0 Michelin Cup 2 is rated C suggests that there is still very significant difference in characteristics.
Wow. And you believe the ratings on the sidewall actually mean anything that relates to the real world?!Tyres are an incredibly complicated component. It takes some very serious computers to model a tyres behaviour up to limit on dry Tarmac, and when you're talking about wet surfaces....you may as well use a random number generator.
The same can be said about physical testing techniques. There just isn't a reliable way to get definitive metrics from a tyre test. How do you even classify 'grip'? And how do you encompass the subjective feel of grip and the way a tyre recovers it in one rating? You can see this is action in most magazine tyre tests. A tyre may score well on braking distance and maximum lateral acceptation, but looses terribly on subjective feel and lap time due to it being peaky or lacking in feel.
Tyre companies are forced by legislation to produce standardised ratings, but it's hugely misleading, especially on a performance tyre. This is illustrated perfectly by the new 'wet grip' ratings brought in, in the last few years. Winter tyres score fairly terribly on this because the test is at a specified (high) temperature which is totally outside the operating temp of a winter. In the real world, in UK rain, when it's 10deg or less, the winter will wipe the floor with a summer.
If you really still don't believe me, go out and buy any book on vehicle dynamics. The tyre is 100% the most important component in suspension design and handling feel. 1000s of hrs are spent tuning tyres to satisfy the performance specifications of a a vehicles dynamics, and zero attention is paid to the 'grip' rating on the sidewall. It means absolutely nothing....
bcr5784 said:
Yes but the fact that for my Cayman an N0 rated Goodyear F1 or Pirelli Zero rear is rated A for wet grip and a N0 Michelin Cup 2 is rated C suggests that there is still very significant difference in characteristics.
Wow. And you believe the ratings on the sidewall actually mean anything that relates to the real world?!Tyres are an incredibly complicated component. It takes some very serious computers to model a tyres behaviour up to limit on dry Tarmac, and when you're talking about wet surfaces....you may as well use a random number generator.
The same can be said about physical testing techniques. There just isn't a reliable way to get definitive metrics from a tyre test. How do you even classify 'grip'? And how do you encompass the subjective feel of grip and the way a tyre recovers it in one rating? You can see this is action in most magazine tyre tests. A tyre may score well on braking distance and maximum lateral acceptation, but looses terribly on subjective feel and lap time due to it being peaky or lacking in feel.
Tyre companies are forced by legislation to produce standardised ratings, but it's hugely misleading, especially on a performance tyre. This is illustrated perfectly by the new 'wet grip' ratings brought in, in the last few years. Winter tyres score fairly terribly on this because the test is at a specified (high) temperature which is totally outside the operating temp of a winter. In the real world, in UK rain, when it's 10deg or less, the winter will wipe the floor with a summer.
If you really still don't believe me, go out and buy any book on vehicle dynamics. The tyre is 100% the most important component in suspension design and handling feel. 1000s of hrs are spent tuning tyres to satisfy the performance specifications of a a vehicles dynamics, and zero attention is paid to the 'grip' rating on the sidewall. It means absolutely nothing....
RacerMike said:
If you really still don't believe me, go out and buy any book on vehicle dynamics. The tyre is 100% the most important component in suspension design and handling feel. 1000s of hrs are spent tuning tyres to satisfy the performance specifications of a a vehicles dynamics, and zero attention is paid to the 'grip' rating on the sidewall. It means absolutely nothing....
I don't know what to believe (having read, and mostly understood, Milliken and Milliken) and my family having spent 20 years in motorsport (at the pointed end) I'm well aware of the importance of tyres, but I think there is more than a little BS in this area. As I have said I can well understand why manufacturers (like Porsche) could well (quite validly) make an argument for controlling the spec of tyres fitted to their cars - I'm not sure that, for the reasons I give above, that it really works in favour of the tyre buyer.I fully agree that the performance rating is very simplistic and I would certainly like a comparative tyre test to judge which of the tyres that fit my car suit MY priorities (which may not be the same as Porsches). Unfortunately I'm very unlikely to see a comparative test of N0 tyres BECAUSE they are specific to Porsche. So for example if I had a Spyder for dry weekends, wet grip would be low on my priorities, but for a DD much higher. If I did a lot of long motorway journeys then tyre roar would be a consideration ... and so on.
Edited by bcr5784 on Sunday 29th March 12:35
Edited by bcr5784 on Sunday 29th March 18:15
Edited by bcr5784 on Monday 30th March 08:14
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