They have cycled on the Rail Trail together but this is the first time they have entered a serious race as a family.
Former school teacher George Sutherland (81) has been the inspiration for his active family.
He will be joined in the 5km ride by his granddaughter Ashleigh Beales (20). His daughter, Shelley Beales (54), and sons Andrew (52) and Simon Sutherland (50) will ride the 17km race.
''I don't look on it as a race, believe me,'' George said.
''I thought it was just a ride together.''
But George is taking the event seriously.
''I have been riding a circuit around the roads for 30min each day to try and get a bit more cycle-fit,'' he said.
George was an enthusiastic cyclist when he was growing up in Invercargill.
''Me and my mates would cycle from Invercargill to Christchurch, post a letter, and come home,'' he said. He has also run three marathons and has a best half-marathon time of 1hr 27min 20sec when he finished 10th in the Dunedin event in 1980.
He suffered a serious heart attack 23 years ago but has come back smiling, and does maintenance work on the walking tracks around Dunedin each week.
Shelley (54), the fittest member of the family, ran the New York marathon in 2010 and climbed Mt Kilimanjaro two years ago.
It was her brainchild to have the family compete together at the El Dorado event.
''There is nothing like being out with my brothers and having my Dad and my daughter there as well,'' she said.
''I'm looking forward to be out there with my family. It will be pretty cool.''
How did the idea come about?''Simon sent me the website and before I knew it I was signing up the five of us for the race,'' Shelley said. The preparation has varied. George has cycled round the block, Simon has spent time surfing the Dunedin beaches and Ashleigh has had her bike serviced by her mother. Andrew is naturally fit.
Simon (50), a draughtsman, has cycled off and on since his schoolboy days but has switched to a mountain bike only over the last 12 weeks.
''I'm stoked to be doing it,'' he said.
''Shelley got me back into riding after a bit of a hiatus. It's great to be riding with her again.
''Dad's always been there when we've gone on our bikes. It will be fun with him as well.
''He has been an inspiration for us and has been running marathons since the age of 40. We were surprised when he had a heart attack because he seemed to be so fit. I used to run with him every morning.''
Ashleigh (20) typifies the third generation.
''It's so nice being part of a very close family that can all enjoy the same activities. I think we're really lucky to do the race together,'' she said.
The walking, running and mountain biking event will be held on one of Otago's historic sheep and beef stations, El Dorado, at Ramrock Rd, near Waikouaiti.
There are three races: 5.5km family walk, run and mountain bike; 17km run and mountain bike, and 35km mountain bike.
