Conversation so far:
Did Graeme Obree use an unusual bike?
Graeme Obree called his bike Old Faithful.
Was Graeme Obree's bike Old Faithful custom made?
Old Faithful has a narrow bottom bracket, around which the cranks revolve, to bring his legs closer together, as he thought this is the natural position.
How did the design affect Graeme Obree bike's performance?
Graeme Obree's bike Old Faithful has no top tube, so that his knees did not hit the frame.

Question: How else is it advantageous?
Self-contained rewrite: How else is Graeme Obree's custom bike Old Faithful advantageous aside from not having a top tube, so that his knees did not hit the frame?