[alexk]

Originally Posted by karbonkid

Alex, Michelin replied to my enquiry and agree this is put down to water displacement and to help reduce noise.

Michelin's reply:

"Thank you for your enquiry about Michelin Pilot Sport Cup tyres.

The slots on the outside of the tread pattern are there to improve
performance in the wet as they provide storage areas for water and biting
edges to break the water film.

The groove length is varied to help mask the level noise
heard inside the car (hence the random arrangement which helps to reduce
specific frequencies). The size and spacing of the main tread blocks is
also varied in a similar fashion, again to reduce the impact of tyre noise.

Thank you for your continued support."

Its now a little clearer as to why the R888 may suffer with its whining due its repetitive arrowhead pattern.

I can now sleep tonight!

Cool stuff