Armour Save if Cavalry
Shield or light armour
Shield & light armour or heavy armour only
Shield & heavy armour
Riders with shields & heavy armour, riding barded mounts
Cavalry models that consist of a mount and a rider (but not those consisting of a single creature, like a wolf or a warhound) automatically have an armour save of 6 even if the rider is wearing no armour. This represents the extra protection afforded by the mount to the rider. If the rider is armoured, then his armour save will be 1 better than it would be if he were on foot, or 2 better if the mount is wearing armour (ie, barding) as well.
For example, a Man wearing light armour and carrying a shield has an armour save of 5+ on foot and 4+ when mounted.
Note that this bonus only applies to cavalry and not to models riding monsters. Rules forare discussed later.
To continue our previous example, the Goblin player has scored 1 wound on the Elf troops. Since the Elves are mounted and wearing light armour, their armour saving throw is 5+. The Elf player rolls a 2 and so the Elf is slain. If he had scored a 5 or 6, the arrow would have bounced off and left the Elf unharmed.