North Yorkshire Police is today appealing for witnesses and information about the theft of a mountain bike near Fremington, Richmond.
It happened near The Dales Bike Centre during the Ard Rock mountain bike event at around 7.30pm on Friday, August 3.
A competitor in race had left his bright yellow 2015 Orbea Rallon leaning against the bike centre while on the phone.
A man described as medium build, around 5ft 10ins tall with wavy ginger hair wearing a peak cap and mountain biking gear got on to the bike and rode off towards Reeth.
A number of competitors and the victim tried to chase him but the offender got away.
It is possible a vehicle was waiting nearby, police said.
The bike is "very distinctive and rare".
It has been customised and now has red anodised lowest gear on the back end and Fox 34 forks. It also has a red chain tensioner at the bottom of the front chain ring and a red chain guide above the front chain ring.
It is worth around Â£2,000.
In particular, we are appealing for information from anyone who may have had a Go-Pro or Dash camera on at the time and has noticed anything suspicious in the area or that may have been offered the bike at the event.
Anyone with information is asked to contact PC 1255 Jack Dodsworth at North Yorkshire Police on 101.
Quote the North Yorkshire Police reference number 12180143112.