It was stolen from the garage of a house on Burnside Walk, between 12pm and 6pm on Monday 16 December 2013.
The dark grey bike, which has the word Voodoo written in black on the frame, has disc brakes and is valued at £500.
PC David Minto, of Harrogate Safer Neighbourhood Team, said: If you have any information about this theft, or have seen the bike since it was stolen, I urge you to come forward and contact the police straight away.
I am particularly interested in hearing from anyone who may have been offered it and ask them to get in touch as soon as possible.
Anyone who can assist with this enquiry is asked to contact Harrogate police on 101, select option 2 and ask for David Minto. Alternatively, information can be emailed to firstname.lastname@example.org
Or call Crimestoppers anonymously on 0800 555111, quoting reference number 12130217786.