Father-of-two Colin Anderson collapsed while taking part in the Pedal for Scotland ride between Glasgow and Edinburgh on Sunday.
He was treated by paramedics close to Avonbridge, near Falkirk, then taken to Forth Valley Hospital, but could not be saved.
His wife Norma, son Fraser, 28, and daughter Stacey, 31, are “heartbroken”.
Speaking to The Scotsman, Mrs Anderson said: “He was a good man. He did everything for everybody, for the kids and me - we are lost.
“He was a gentle giant, and very much a family man.
“He was funny and laid-back.
“He loved his cycling, and also took up woodwork. He was self-taught, making all sorts of things - from toy boxes to rocking horses. He even made a sign for our daughter’s wedding.
“He was very creative, and just one of life’s good people.
The 57-year-old, from Glasgow, worked for Bank of Scotland.
He had been a passionate cyclist since his teenage years and rode up to 50 miles most weekends.
He was raising funds for the Scottish Association for Mental Health (SAMH) when he died, riding with his son Fraser and best friend Ian Laidlaw as part of the Fat B'Stards Bicycling Fraternity.
Mrs Anderson says her husband was a fit man, with no known health issues.
“It’s a tragedy. It was totally unexpected," she said.
“He was out cycling every weekend. It wasn’t like he had just decided he would try it, to see if he could do it.
“As a family we’re just broken. Colin was our everything and I don’t know how we’ll get through without him.”
Mrs Anderson has expressed gratitude to the medics who attempted to save her husband’s life.
“He had no warning of what was about to happen and had been feeling well,” she said.
“They had stopped five minutes before he took ill for a drink and an energy snack - Ian said Colin was in fine form, and was always pushing ahead.
“So they got back on their bikes and there was a hill - Colin cycled up the hill but Ian got off and walked. When he got to the top of the hill be was aware someone was on the ground.
“It took him a minute to realise it was Colin. By that point he was surrounded by an accident and emergency consultant, intensive care nurses, a GP, who were all taking part in the event, so he had the best of care.
“Resuscitation was started immediately - these guys were in the race and just happened to be around Colin when he collapsed. The paramedics arrived in no time and they continued treating him, then took him to Forth Valley hospital. But unfortunately it wasn’t to be.”
The Shawlands bank where he worked was unable to open on Monday morning as staff and customers struggled to come to terms with the tragic news.
Tributes have been pouring in and there has been a huge surge in donations to Mr Anderson’s sponsorship page on the Just Giving website.
In his final post on the page, ahead of Sunday’s ride, he said: “Hi folks, wee update as Sunday approaches. Thanks to everyone who has donated to SAMH. I am blown away by your generosity, amazing generous people. £215 raised on my page so far, with more to add from my sponsor sheets pledged by friends and workmates. Roll on Sunday.”
The total raised has rocketed past £4,300 in the past couple of days, with many people sending condolences and paying tribute.
Motherwell Football Club, where Mr Anderson was a season ticket holder, also sent a message of sympathy and encouraged fans to support his fundraiser.
Anyone who wants to donate can do so at www.justgiving.com/fundraising/colin-anderson28.