Is the disc mounted onto the main axle?

Are we talking about the hardox bar part here? If so, not directly, its mounted onto the outer axle, which is mostly mounted onto the inner wheel hubs and theyre mounted to the main axle

How is the disc driven (chain/belt/direct gearing?)

Direct gearing

Are the wheels protected from a lucky front on attack?

That would be impossible while maintaining proper invertability, so no.

In the picture, there looks like a gap in between the 2 semi-circular wheel protectors, is this true oris the gap filled?

The gap isnt filled.

How are the wheels driven?

Dirtect gearing.

What voltage do you run the disc motor at?

Thought Id put this in the stats, sorry. 36 V

May Tracks will gladly take on Nitrogene again.