James Cracknell was the first celebrity over the finish line with a time of just over four hours and 36 minutes.
"It was brilliant," he said afterwards.
"Apart from my time, the best thing was the fact that there were thousands of people flooding into the Olympic Park, not to watch something, or see top performers, but to do something themselves.
"If there are any legacy discussions going on, that is the selling point for me - nearly 20,000 people riding out for 100 miles. I can really see this being like the London Marathon."
More top news
Outbreaks of rain and strengthening winds will affect southernmost parts of England and Wales today.
An earlier debate on the issue was suspended as an 'expression of support' following the Westminster terror attack.
Five people were killed and dozens more were injured after a car and knife attack in the capital on Wednesday afternoon.