Even if the balrog was twice the size of a man (I think it says this in the fall of Gondolin of balrogs being twice man high) it should have had no problem crossing the bridge. This is shown by the fact that it did in fact go onto the bridge and began to cross, it took Gandalf's breaking the bridge to stop its advance.
__________________
His sword was long his lance was keen
His shining helm afar was seen
The countless stars of heavens field
Were mirrored in his silver shield
|