Pirelli (singular)is the name of a huge, Italian based, multi-national company; that produce tires for vehicles, trucks, and motorcycles. They focus on high technology and high performance tires.
Meaning-
So, did you [perhaps] hear it from a song "my Pirellis' on role.." ? If so, the artist is probably, intentionally using the phrase improperly. Maybe, to make it sound more like slang.
1. "role" probably supposed to be spelled roll. Example: rolling on tires
2. "Pirellis" is just the plural form(more than one) of Pirelli.
Hope that helps.