Brian Millington was preparing to 'ride against the floods' during a cycle from Plynlimon in Mid Wales to Bridgnorth in March, but was scuppered by the coronavirus pandemic.
Raising funds towards flood defences along the River Severn as well as towards the community store Our Green Shop, Brian plans to take on the challenge this weekend despite only having use of his right lung.
Having never smoked, the 65-year-old from Highley was diagnosed with lung cancer in 2016 and was declared cancer-free earlier this year – four years after an operation to remove the majority of his left lung.
Blaming his condition on air pollution during the 34 years spent working in London, Brian said he is "passionate" about tackling climate change.
He said: "To celebrate being free from lung cancer, I promised to ride 80 miles along the course of the Severn to raise funds to combat climate change.
"I managed to cycle a token trip between Bridgnorth and Ironbridge.
"The lockdown prevented me from cycling the 80-mile route, but I'm eager to go this weekend while there are few restrictions.
"At last, this Friday and Saturday I aim to complete the trip from the banks of Plynlimon to Bridgnorth, following the course taken by the devastating floods earlier this year."
Volunteers from Our Green Shop, based in Bridgnorth, will launch their delivery service on Monday, and will continue to raise funds to set up a permanent shop in High Town.
Supporters can donate by visiting justgiving.com/crowdfunding/ride-against-climate-change