The A40A has a hardness measure between 55-57 at room
temp and is a cross between a Firestone YFA (soft) and YGF (hard). The
A40A is a tougher version of the A30A. It is a more versatile compound
that is suitable for all classes and track surfaces found in asphalt
venues. The A40A will accept heat better and have better wear
characteristics on abrasive tracks.
If there are any questions, please feel free to
contact Adam Batton.