FIVE Bunbury men putting their bodies on the line to raise money for the Royal Flying Doctor Service are discovering so many people have been helped by the service.

Aaron Turner, Craig Johnston, Chris Grey, Paul Cusack and Steve Adams are taking part in The Gibb Challenge, a 660km team relay event along the demanding Gibb River Road.

Riders will start from Derby on Sunday and finish at El Questro Wilderness Park on May 25.

Teams of between two to six riders need to raise at least $1000 to join in but the Bunbury men have raised well over that, sitting at close to $12,000 between them.

Mr Turner said they set a target of $5000 but had found so many people had been helped by the service that donations were generous. Their new goal was $15,000.

“I think it’s close to home for a lot of people,” Mr Turner said.

Only Mr Johnston has experienced the event so for the rest, it is like diving into the unknown.

“We don’t really know what to expect,” Mr Turner said.

On day one Mr Turner expects each team member to ride between 50km-60km and then 70km-80km between them after that.

To prepare the group has done some training rides and although each team member had different levels of skill and fitness, they all enjoyed mountain biking and were excited about what they would experience on their adventure.