As nouns the difference between bickie and backie
is that bickie is (slang) biscuit while backie is a ride on the back of a bicycle or motorbike.
bickie
English
Alternative forms
* biccie
* biccy
* bicky
backie
English
Noun
(
en noun)
A ride on the back of a bicycle or motorbike.
References
* Google Books: [https://www.google.co.uk/search?tbs=bks%3A1&tbo=1&q=%22a+backie%22+bike&btnG=Search+Books&gws_rd=ssl]