do pikemen get strength bunus against riders on monsters ,
in the rules says only monsters chariots and cavalery and it also says (note it only applies to this units mension above)?

im having a harch twist about this so I want to resolve this issue.
thanks for answering.

I don't know if there's an official ruling on this, but I'd say the Strength bonus works against them (or at least most of them).
Fluff wise, it'd seem appropriate for anything that has speed to give the pikemen a strength bonus- I'd say anything which pursues/flees 3D6 or more (including flyers not using ground movement).

I compleatly agree with Geep. Just think about it, if a horse and rider get the huge amount of speed and momentum that makes the pikes so effective against them. Then a monster and its rider will have a way way huger momentum taken into account the bulks and mass of most monsters. So ye, it should work against both monsters and their riders. At least thats what my club does.