To go all the way over pub – that's some bike! (8)
I believe the answer is:
crossbar
'that's some bike' is the definition.
(part of a bicycle)
'to go all the way over pub' is the wordplay.
'to go all the way over' becomes 'cross'.
'pub' becomes 'bar' (both are drinking establishments).
'cross'+'bar'='CROSSBAR'
(Other definitions for crossbar that I've seen before include "Horizontal piece, on a bicycle say" , "Goal's top member" , "Part of bicycle or goal" , "Horizontal beam over goal posts" , "what one may tip over?" .)