Quote:
Originally Posted by DrFerry
Correct. Your PSS are not directional, but they are asymmetric and employ dual tread compounds as one design strategy i.e. the outer tread shoulder compound is dry focused and different to the inner tread shoulder compound which is more wet focused.
The practice of flipping the tires on the rim has merit only in a dry track environment and only when a homogenous tread compound is employed with a non directional tread design. The Michelin PS2, PSS and PS4S tire product lines all use asymmetric, dual compound, design strategies. Hence, there is a reason why their inner sidewall states "Inside".
To paraphrase what others have already stated in earlier posts: With some tires, used solely on a dry track, flipping them on the rim has been done to extend tire life in a track application. However, one has to be very careful of the engineering constraints designed into the product to avoid not degrading dry grip, vehicle balance, and stability [ assuming a dry track].
For example: Below is a photo of an OEM PSCup 2 tire that uses 4 different compounds across the face of its tread. So flipping this type of tire can reduce dry grip when the alternative wet compound focused tread shoulder faces the outside.
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Here's an illustration of the PS4S dual compound design strategy.
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And PSS
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Source link and other more detailed information:
https://motoiq.com/not-all-michelin-...ed-the-same/4/
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Not to confuse things any further, but if a directional tire were to be flipped on the rim and used in a wet environment its tread will actually pump water "into" the contact patch rather than away from it.. This is the reason why directional tires use a marking of some type to indicate the direction of rotation in service. |
Great to note assymetric compounds since the star spec PS4S for BMW G80 now have 5 alternating compounds!