The five-times World Cup downhill mountain biking champion has had his £7,000 bike stolen in Edinburgh just days before he is due to race for the title again.
Aaron Gwin, from California, had his Intense M29 downhill mountain bike taken from a van at a hotel in Clermiston on Monday night.
He is competing at the Mountain Bike World Cup at Fort William this weekend.
The 31-year-old has put up a reward for the bike's return.
The team were spending a night in Edinburgh to break up their journey to Fort William when the bike was stolen.
Todd Schumlick, Intense Factory Racing team manager, told the BBC Scotland news website Aaron was very upset by the theft.
He said: "We ran out of space in our specially secure van and had to put his bike in another van overnight in Edinburgh.
"They ruined the door of the van and managed to get it out of a side window as it didn't have wheels on it.
"Aaron is upset because it is the size he wants to race on but luckily we have managed to source another one and its being distributed to us.
"We have raced all over the world for 10 years now and have never had a bike stolen before.
"It's a sign of the times and will make us more vigilant in the future."
It costs about £500 annually to insure a bike of this value, so a decision had been taken not to insure it.
He added that a young man on a scooter had apparently been seen scoping out the area that night.
Police Scotland have urged anyone with information about the theft between Monday 27 and Tuesday 28 May to contact them.