A man raising money for a cancer charity after surviving Hodgkin Lymphoma as a child died in the RideLondon 100-mile (160km) event.
Robin Chard, 48, from Bicester, suffered a cardiac arrest after about 25-miles in Sunday's cycling event and died in hospital, the organiser said.
He was taking part as a "personal crusade" after his father and stepfather died from lung cancer.
His wife Vickie said he was doing "something he loved".
Donations to Mr Chard's fundraising page, on behalf of Cancer Research UK, have already passed ?10,000.
She said: "Robin was doing something he loved to raise money for Cancer Research UK, a cause that was very important to him after losing his father, his mother's partner and my mother to cancer.
'Amazing'
"I'd like to thank everyone who has helped and supported Robin and me, especially the event stewards, the event team and the amazing staff at Kingston Hospital."
RideLondon said Mr Chard suffered a cardiac arrest at Kingston Bridge "and although he received immediate treatment from fellow riders and medical personnel at the scene, he died later in Kingston Hospital".
"Everyone involved in Prudential RideLondon would like to express sincere condolences to Robin's family and friends."
Tributes have been left on Mr Chard's JustGiving page.
One message read: "Hi daddy, I'm so proud of you. Well done for getting as far as you did. I love you so so so much, I know you'll be proud of all the money you raised. You did such an amazing thing. I love you."
A message signed by Ashley read: "So sorry to hear about the tragic accident, I hope this page serves as a legacy of your hard work and fund raising for a great cause."
Judie Pierce added: "A sad ending to someone doing an act of generosity and kindness for others. May you rest in peace and your family and friends be proud of you."
Robin Chard, 48, from Bicester, suffered a cardiac arrest after about 25-miles in Sunday's cycling event and died in hospital, the organiser said.
He was taking part as a "personal crusade" after his father and stepfather died from lung cancer.
His wife Vickie said he was doing "something he loved".
Donations to Mr Chard's fundraising page, on behalf of Cancer Research UK, have already passed ?10,000.
She said: "Robin was doing something he loved to raise money for Cancer Research UK, a cause that was very important to him after losing his father, his mother's partner and my mother to cancer.
'Amazing'
"I'd like to thank everyone who has helped and supported Robin and me, especially the event stewards, the event team and the amazing staff at Kingston Hospital."
RideLondon said Mr Chard suffered a cardiac arrest at Kingston Bridge "and although he received immediate treatment from fellow riders and medical personnel at the scene, he died later in Kingston Hospital".
"Everyone involved in Prudential RideLondon would like to express sincere condolences to Robin's family and friends."
Tributes have been left on Mr Chard's JustGiving page.
One message read: "Hi daddy, I'm so proud of you. Well done for getting as far as you did. I love you so so so much, I know you'll be proud of all the money you raised. You did such an amazing thing. I love you."
A message signed by Ashley read: "So sorry to hear about the tragic accident, I hope this page serves as a legacy of your hard work and fund raising for a great cause."
Judie Pierce added: "A sad ending to someone doing an act of generosity and kindness for others. May you rest in peace and your family and friends be proud of you."