Ross Mitchell, 41, from Auchtertool, will set off on Saturday and ride over 530 arduous kilometres – via some of the biggest mountain passes in Scotland.
He has encouraged 50 others riders from across the UK to sign up to the challenge, and raise funds for Children’s Hospice Association Scotland (CHAS).
The engineer said he wanted to push the boundaries of what is possible- and set up a challenge that tested the limits of endurance cycling.
He added: “Deciding on a route and gauging what is achievable has been the hardest part.
“The Cairngorms are an unfortunate side effect of having to avoid the A9, and this presents a huge amount of climbing. In total, it’s a 6000m ascent, which is over double anything I’ve previously done in a day. It will be the equivalent of cycling up Ben Nevis four times or two-thirds of Everest.”
Ross has taken part in a number of endurances races across Europe and commutes over 50 miles per day. Last year he was the fastest British rider in the Mallorca 312 Gran Fondo, completing 312 km round the island in under 11 hours.
The 41-year-old - who is related to the renowned Puddledub family at Clentrie Farm in Fife - has already garnered a great deal of interest in the event from within the cycling community, and 50 riders from have signed up.
All riders involved have been asked to make a donation to children’s charity CHAS - a gesture which has been warmly welcomed by Stephen Hart, the charity’s Community Fundraising Manager.
He said: “We’re delighted that the Lang Way Doon has chosen to support CHAS, which is the only provider of hospice services in Scotland for babies, children and young people with life-shortening conditions.
“At CHAS, we want to make sure that wherever there’s a child in Scotland with a life-shortening condition, we’re on hand to support their entire family.”
Mr Hart added: “The vital funds raised by this challenge will help keep the joy alive for families facing the most difficult time imaginable, by ensuring that no matter how short their time together may be, it is filled with happiness.”
“The cycle presents an enormous personal challenge for all of the riders taking part and we wish them the best of luck in this extraordinary event and thank them for all their amazing support.”