Complex sentence: Seiberling tires are no longer sold in the US, but the brand name still in use in some countries, manufactured at Firestone ´ s plants, they are marketed as a cheaper, second-class type of tire in selected sizes.
Split into simpler sentences: Seiberling tires are no longer sold in the US, but the brand name is still in use in some countries. Manufactured at Firestone ´ s plants, they are marketed as a cheaper, second-class type of tire in selected sizes.