What does hardness mean for a petanque boule?
The boule's hardness is expressed in the ROCKWELL "HRC" unit or in kg/mm².
For example, 39 HRC corresponds to 124 kg/mm².
The higher the number, the harder the boule. The harder the boule, the less likely it is to get damaged, and the higher its elasticity, and vice versa.Regular players who use soft boules should consider frequently changing their boules to avoid undermining their game.