TB993tt:
fritz:
OBG:
You may have hit on something. The automotive supply business is rather cut throat. Maybe Pirelli just out bid Michelin.
Since Porsche always approves multiple tyre brands for each model so that it is not entirely dependant on one manufacturer, that will not be the explanation. It's more likely that Michelin could not fulfil one of the technical criteria set by Porsche, as someone mentioned above, and had to be sent away to do some more homework.
Fritz, do you really believe this that the MPSS could not fulfill one of the technical criteria ? If so what sort of criteria would you guess at ?
Car manufacturers, when approving specific tyres for their products, will have objective values for various characteristics whose complete fulfilment they will strictly insist on for very good reasons. If even an otherwise favoured supplier cannot fulfil then he has to do some more homework, as I wrote above. There can't be any free passes, otherwise you might just as well bin your list of objectives.
We are just speculating that that is what has happened here, but another post here today suggesting that Porsche's approval of the MPSS for some models has been confirmed by PCGB as being imminent would suggest that the speculation is close to the mark. Why else should it come at this late date?
I wouldn't speculate on which criterion might have caused problems, as that would just be a wild guess with no factual basis.
I too have noticed that a lot of drivers who have fitted MPSSs to their Porsche's are extremely pleased with them, but those are subjective opinions arrived at without any knowledge of any problems which those tyres may or may not have had fulfilling the objective targets, or of how relevant any such problems might be for them.
I have driven the big 325 size MPSS over 200mph many times and have to say there is always a slight inkling of doubt because it doesn't have the "N" approval..... this and the fact that the 325 size is not manufactured or distributed in Europe but only in the USA which worries me slightly since cars drive slowly over there and just maybe this particular tyre is for domestic market only ?
Without in any way wanting to appear unduly alarmist, the combination of very high rear axle weight, very high speeds and high torque loads which can come together on your particular car are far from the easiest for a tyre manufacturer to fulfil.
Personally, I would have reservations about using tyres under these conditions which I specifically knew had not yet been released for the application in spite of the fact that I would normally expect it to be a high priority matter for the people responsible for that approval.
I have often thought that Bugatti must sh!t in its collective company pants every time an owner calls to say that he wants to drive his Veyron at 400km/h and asks them to send along the obligatory technician and fresh set of tyres for use on that drive.
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fritz