mounted grappling question

[fl8m]

I've started a campaign where the pc's are for the most part mounted combatants. How exactly does grappling work against a mounted opponent? are they considered large? do they have to grapple the horse too? are you just immune to grapple if your mounted? I'm rather confused

also when sundering you and your opponent roll to strike with the weapon being sundered. so it's simple when bad guy #1 is trying to break the good guys sword. However, when bad guy #1 decides to try to break the shield what penalties apply to the opposed roll for the good guy? does he take the dual wielding penalties? does he still lose his ac bonus from the shield? What if the bad guy wants to sunder the good guys armor for full plate it's hardness 10 and 40hp but what opposed attack roll does the good guy use? just BAB and STR?

 

[shilsen]

I've started a campaign where the pc's are for the most part mounted combatants. How exactly does grappling work against a mounted opponent? are they considered large? do they have to grapple the horse too? are you just immune to grapple if your mounted? I'm rather confused

It's not spelled out explicitly in the rules, so I'd treat it like tripping a mounted opponent. You use the modifiers for the rider, not the mount. If you manage to successfully grapple the rider, you pull him from his mount.

also when sundering you and your opponent roll to strike with the weapon being sundered. so it's simple when bad guy #1 is trying to break the good guys sword. However, when bad guy #1 decides to try to break the shield what penalties apply to the opposed roll for the good guy? does he take the dual wielding penalties? does he still lose his ac bonus from the shield?

Not explicitly spelled out again, so it's open to DM judgement. I'd make it an opposed roll without dual-wielding penalties. And the defender would still retain his shield bonus to AC.

What if the bad guy wants to sunder the good guys armor for full plate it's hardness 10 and 40hp but what opposed attack roll does the good guy use? just BAB and STR?

You can't sunder worn armor. This has been spelt out in the FAQ, IIRC.