Porsche 911 UK Enthusiasts Online Community Discussion Forum GB

Welcome to the @Porsche911UK website. Register a free account today to become a member! Sign up is quick and easy, then you can view, participate in topics and posts across the site that covers all things Porsche.

Already registered and looking to recovery your account, select 'login in' and then the 'forget your password' option.

991 S Twitches

Cyclops

New member
Joined
2 Dec 2012
Messages
4
Has anyone else with a 991 S experienced the following: At random (but very noticeable at around 70mph) the steering veers to the right for about 2 seconds and then very noticeably corrects itself? If you let go of the steering wheel and you were in the inside lane on the motorway you would be in the fast lane within a second.

The car is a 991 s with PDK, Sport Chrono, 20" Sport Classic wheels etc.

The car has been with Porsche for about a week, fitted in with some official standard recall items. Porsche couldn't work out what it was until they got in contact with Germany and discovered that a rear tyre was incorrect.

I had to replace my rear left tyre at a local garage, I called in the details of the tyre that I required but crucially was unaware the you had to buy the fabled "N" rated tyre. I was very dubious that this could be the problem. However, having forked out £380 for the replacement yesterday I have no twitching.

I thought the 'N" rated stuff was nonsense. However, Porsche Germany said that data obtained from my car indicated that the wheel was turning at a slightly different rate (compounds and circumference were mentioned) this lead to the car self-correcting itself to make up for the differences. I wouldn't have thought this possible if it wasn't for the fact that the problem has now been resolved.

I would be very interested to hear if anyone else has experienced the same issue. Also, I now have a part worn tyre sitting in my back garden with about 700 miles on it that I don't need. Does anyone want to make an offer for it? It's a Pirelli PZero 235/30/zr20.

The lone car from Porsche was a standard Boxster with PDK. The new version looks nice and handles really well. You can really feel that it's mid-engined. The only downside was the lack of a soundtrack and there is no torque, though I have probably been spoiled by my 911 to be fair.
 
Cyclops said:
I had to replace my rear left tyre at a local garage, I called in the details of the tyre that I required but crucially was unaware the you had to buy the fabled "N" rated tyre. I was very dubious that this could be the problem. However, having forked out £380 for the replacement yesterday I have no twitching.

You were not the first person to wrongly assume that the N-rating of tyres is just marketing BS to try to channel more turnover from the replacement tyre business to OPCs.
 
N-rating per se is not that important (unless you have a warranty).

eg Michelin Pilot Super Sports

Many N rated tyres started life as just a high performance tyre, N-rating just means Porsche certify it for use - much like the oil specification and approval.

Of course, what the N-rating provides you with is a guarantee of an adequate level of performance for a particular vehicle and compatibility.

The point is to both assure performance as the factory intended and keep you safe if tyre choosing isn't your specialty.

If in doubt, or you have a choice, fit the N-rated one (but check it is N-rated for your specific model).

However, what will result in death is mixing tyres on the car (more so AWD variants) and certainly per axle.

Don't second guess the recommended oil or fuel grades either.
 
forcedinduction said:
eg Michelin Pilot Super Sports

I'm confused... These are not N rated? My GT3 runs these and the rear set were supplied and fitted by an OPC
:dont know:
 
Please read my statement in context:

eg Michelin Pilot Super Sports

Many N rated tyres started life as just a high performance tyre, N-rating just means Porsche certify it for use - much like the oil specification and approval.

Michelin Pilot Super Sports are NOW N-rated (for about a year), but they weren't when Michelin released them to the world for any marque's performance application.
 
forcedinduction said:
Please read my statement in context:

eg Michelin Pilot Super Sports

Many N rated tyres started life as just a high performance tyre, N-rating just means Porsche certify it for use - much like the oil specification and approval.

Michelin Pilot Super Sports are NOW N-rated (for about a year), but they weren't when Michelin released them to the world for any marque's performance application.

News to me. :dont know:
I understood that the N-rating of the PSSs for many Porsche sizes including those for the 991, has been delayed, but is now expected in the "near future".
 
Oh dear, perhaps I'm wrong, but I was thinking about the 997 sizes, not the 991 versions, if that makes any difference?

Perhaps Roro should speak with PCGB to confirm his warranty isn't void.
 
forcedinduction said:
Oh dear, perhaps I'm wrong, but I was thinking about the 997 sizes, not the 991 versions, if that makes any difference?

Perhaps Roro should speak with PCGB to confirm his warranty isn't void.

No it doesn't, as 997 owners are also complaining on the net that they cannot currently buy N-rated PSSs.
 
OK, so going back to my first post, when they get N-rated, that will be a perfect example of:

A) the best technology not necessarily being (yet or ever) approved - eg batteries etc too

B) the longest gestation of a general market high-performance component being then approved - ie N-rating won't change how good the tyres are, just that they won't invalidate your warranty!
 
forcedinduction said:
OK, so going back to my first post, when they get N-rated, that will be a perfect example of:

B) the longest gestation of a general market high-performance component being then approved - ie N-rating won't change how good the tyres are, just that they won't invalidate your warranty!

You appear still not to have understood the significance of Cyclops post above:

"I had to replace my rear left tyre at a local garage, I called in the details of the tyre that I required but crucially was unaware the you had to buy the fabled "N" rated tyre. I was very dubious that this could be the problem. However, having forked out £380 for the replacement yesterday I have no twitching.

I thought the 'N" rated stuff was nonsense. However, Porsche Germany said that data obtained from my car indicated that the wheel was turning at a slightly different rate (compounds and circumference were mentioned) this lead to the car self-correcting itself to make up for the differences. I wouldn't have thought this possible if it wasn't for the fact that the problem has now been resolved."
 
Honestly, you've lost me.

I am not sure what I am supposed to have misunderstood.

Just quoting it again, by definition, adds nothing.

My first post addressed the mix'n'match issues of tyres.

My reading is that one tyre didn't match the other's spec.

Rather than some juvenile point-scoring, please explain what I am missing, or do you just come on here to belittle people?
 
forcedinduction said:
Honestly, you've lost me.

I am not sure what I am supposed to have misunderstood.

Just quoting it again, by definition, adds nothing.

My first post addressed the mix'n'match issues of tyres.

My reading is that one tyre didn't match the other's spec.

Rather than some juvenile point-scoring, please explain what I am missing, or do you just come on here to belittle people?

Now you've lost me.

Cyclops effectively told us that when his car was fitted with two identical rear tyres (meaning brand, model type, dimensions), apart from one being Porsche N-rated and the other not, his car was not driveable).

You then implied in your posts that the Porsche N-rated tyres are just the tyre manufacturer's "standard" version but with a Porsche "stamp of approval" added, and that that stamp is made a prerequisite by Porsche for the car's warranty to be valid:
Quotes:
"the longest gestation of a general market high-performance component being then approved - ie N-rating won't change how good the tyres are, just that they won't invalidate your warranty!"
and,
"Many N rated tyres started life as just a high performance tyre, N-rating just means Porsche certify it for use - much like the oil specification and approval".

Now you are acknowledging that the two tyres which caused Cyclops' issue did not match each other's specifications (= resulting in different driving characteristics), i.e., that the difference is not limited to just a "stamp of approval".

Either you are contradicting yourself or some your statements have been worded ambiguously.
 
I've never come across this problem.

But on the subject tyres, I've managed to puncture 3 of my tyres thus far and it hasn't even a year - total costing running at £1600 now. The tyres puncture very easily :(
 

New Threads

Forum statistics

Threads
124,587
Messages
1,441,766
Members
49,011
Latest member
Mchass
Back
Top