| chuck911 |
Mar 12, 2013 05:24 PM |
Both sizes will fit and work just fine on all the models and wheels offered. Feel free to dig up the post a few months back where I said this was the case, as well as the following post where the late great Gary Sims agreed. People seem to have some idea that the tire sizes Porsche chooses to fit are due to some exact science or clearance requirement when in fact its simply a case of a given rim width being able to accomodate a range of tire sizes that will all work just fine. Within that given range there are probably some measurable variations but as Gary pointed out nobody'll ever notice because the difference in width is only about 2%. As easy as it is to change tire performance with just a few psi more or less it should be easy enough to understand why this would be the case.
So why would Porsche fit the wider tires to the 4S but not the 2wd 991's? Well, even though the performance difference is nil the appearance difference is not. The reason is because of wheel well to tire spacing. Let's say your car is set up to where you can fit two fingers between a tire and the fender with the narrower tire size. So you mount the wider 305's. The 305's are only 1cm wider than the 295's, a measly few percent that won't affect handling or performance. But they stick out 5mm wider to the side, which is TWENTY-FIVE percent of the fender clearance. Nobody will ever notice 2%. Everybody can see 25%. They do it for the look.
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