Cycle ultimately crashed entering ring (5)
I believe the answer is:
pedal
'cycle' is the definition.
(pedal can mean to cycle a bicycle)
'ultimately crashed entering ring' is the wordplay.
'ultimately' suggests the final letters.
'entering' indicates putting letters inside.
'ring' becomes 'peal' (pealing is a kind of ringing).
The final letter of 'crashed' is 'd'.
'd' inserted within 'peal' is 'PEDAL'.
(Other definitions for pedal that I've seen before include "Part of cycle" , "Brake or clutch perhaps" , "Plead for bicycle propeller" , "Foot-operated control" , "Power a bike" .)