[Boromir88]

Hmm, perhaps Balrog's don't actually have wings, but perhaps something on their backs that look very much like wings.~Elentari

The problem with this is the Balrog is described as being 'man-shaped'. Something that is 'man-shaped' means it's form is that of a man's. I don't think something that is man-shaped would have bat wings (or something of that sort) coming out of his back. Just like if something was 'man-shaped' I wouldn't picture a 40-foot horned, and hooved, demon thing like Jackson portrays.

On top of that Durin's Bane was described as 'man-sized' and something man-sized simply wouldn't be able to have wings that when fully spread out reached to a 100 feet...but now I'm getting into repeating myself and so I'll just say this.

A lot of people think there is ambiguity and mystery surrounding the Balrog. They think nothing is known for certain and they're one giant enigma. That's not really true at all, I mean we're not dealing with Tom Bombadil here who Tolkien purposefully left as an enigma. Tolkien gave us a lot of information on his Balrogs, you just have to look for it, it's right there in the text. And I think the only reason people think there is a 'debate' over Balrog's is because of the movies and artists; who when looking at the text are not really even close to being accurate. As artists, and movie-makers are interested in selling their product, so they want to go for the 'coolest' looking pictures for their audience to make more money...and when you do that you often lose the accuracy. And then the public views these movies and pictures, gets these images stuck in their head and instead of looking at the text from an unbiased view, look at the text with the visualization of these distorted images in their head and try to find only things which support that visualization...like: 'and it's wings were spread from wall to wall.'...and completely disregard any other part of the text that plays a factor in determining whether the wings were merely an impression and metaphorical or were literal wings.

Don't get me wrong, because I don't want to sound mean or arrogant, but in most cases that's how it is.

I'll leave you with this...Here is a wonderful description Tolkien gives us of clouds...and it is precisely the same style he uses with Durin's Bane in Moria:

"And out of the west there would come at times a great cloud in the evening, shaped as it were an eagle, with pinions spread to the north and the south; and slowly it would loom up, blotting out the sunset, and then the uttermost night would fall upon Numenor. And some of the eagles bore lightning beneath their wings, and thunder echoed between sea and cloud."~The Akallabeth

Here Tolkien is describing clouds and he says the clouds were 'shaped as if it were an eagle'...there's the simile. Then he extends that simile to keep that imagery of clouds looking like eagles in the readers mind; with...and some of the eagles bore lightning beneath their wings.

Did the clouds morph into eagles? No, that's just Tolkien using language to the great extent that he was able to. He sets up the simile of clouds shaped like eagles, then to keep that imagery going he extends it and actually calls the clouds 'eagles.'

Same things happens in Gandalf's confrontation with Durin's Bane:

'...spread out like two vast wings.'

Then one moment later:

'...it's wings were spread from all to wall.'