Chaos Santa:
Clarification on some of the Bull Centaur Rules for Shields,
Spears, & Great Weapons given that they are monstrous creatures not monstrous cavalry.
Do you get the Parry saved from shield
Do you get +1 strength on the charge with spears or can you fight with next rank
& do the Great Weapon still give you +2 strength
Thank you
TheFNG:
So the answer is that yes, you can use Shields with Great Weapons or Spears. You DO get the +1 AS vs shooting and magic, but you do NOT get the +1 AS nor the 6+ Parry Save during close combat if you take Great Weapons and (I believe, but I’d have to check) you DO get the +1 AS during close combat but DO NOT get the 6+ Parry Save if you use spears. The rule for spears is +1S on the charge, the next round of combat you get +1 Rank of supporting attacks.
I don’t have my BRB so I can’t confirm the Spear and Shield comment, but I believe I am correct.
Bloodbeard:
Don’t know if montrous beast count as mounted - don’t think they do.
Only mounted models gets +1 S on charge. They can’t use for extra rank.
Only footsluggers get +1 rank but not strengh on
According to LoA BCs can’t have spears anyway.
Mounted models can’t use parry save. But again BCs are monstrous beasts.
I see BCs as models on foot. They are beast and not mounted. So that means parry save, rank with spears or 2+ strengh with GWs.
You can use a shield with a spear.
zhatan87:
They count as model on foot :
parry save with shield
fight in extra rank with spear
Chaos Santa:
That’s great thanks and pretty much as I thought it would be,
I can’t really see the point of the spears myself as I don’t know
anyone who’d use them in sufficient numbers to get the third rank
Of attacks.
What are most people’s options a in the additional hand weapon Vs GW
The GW’S seem to make the unit very pricey
furrie:
That's great thanks and pretty much as I thought it would be,You can make a bc train (so 3 in 3 ranks), you don't need complete ranks for spears to work. Just 3 ranks.
I can't really see the point of the spears myself as I don't know
anyone who'd use them in sufficient numbers to get the third rank
Of attacks.
What are most people's options a in the additional hand weapon Vs GW
The GW'S seem to make the unit very pricey
Chaos Santa
Billy Ocean:
I think when FW brainstormed their bull centaurs, they intended them to fight as a hybrid of mounted and unmounted models, using spears to get +1S on the charge, and shields to get a parry save. Of course, without an explicit statement along those lines, we are stuck using them as just unmounted models, so spears become poor option (the train seems a bit unwieldy to me - I like to use the centaurs as a small, highly maneuverable shock unit with Taur’ruk).
I go great weapons every time. Yes they are expensive, but having a fast unit that hits at strength 6 is worth it to me. I use them to charge knights and monstrous cav before they get a chance to charge me. I take 3, plus a Taur’ruk with 1+ re-rollable armor. If you go 2x2, you can force opponents to allocate attacks vs. the Taur’ruk and champion, minimizing damage the unit takes before hitting back with their great weapons.
Kamphre:
This (how do spears work with BC) was asked to Forgeworld and they replied that it was a good question and they will answer someday. It was nearly 2 years ago. 
Hashut’s Blessing:
Forgeworld rules replies by e-mail shouldn’t be taken as official - mostly because they’re not 
Spears are used as for infantry (+1 rank of +1 attack).
Parry save is used as for infantry (6+ Ward Save if they have no other special weapons - spear, additional hand weapon, great weapon).
Great Weapons are used as for infantry (+2S).
We know all of this because their unit type is Monstrous Beasts. The only exceptions to this ruling are Cavalry, Monstrous Cavalry (and maybe Chariots - not got BRB to hand).
Lastly, LoA is the ONLY place they can have spears…