Nick Craig will have to beat a record entry of 1,700 riders if he is to win his fourth consecutive Manx End-2-End Mountain Bike title on Sunday.
The former Olympian, 42, from Hayfield, said: "It's a tough challenge and the field is growing in quality every year."
Despite strong winds, Craig finished the punishing 46-mile race in two hours 57 minutes and 20 seconds in 2010.
Meanwhile, Elliot Baxter will lead the Manx challenge after last year's second place finish.
"Obviously I want to go one better this year. I want to win.
"The conditions aren't great but it's the same for all of us, I can't see any records being broken on Sunday," he added.
More than 1700 cyclists have signed up for the 75km challenge, on 18 September.
Riders will have to tackle a variety of terrain and climb more than 1500m, as they ride from the Point of Ayre in the north of the island to Cregneash in the south.