Richard Bradford said his bike was stolen at some point on Saturday from his mother’s garage in Poulters Lane.
His daughter Megan, who has Friedreich’s ataxia, had been staying with her grandmother after celebrating her 18th birthday on July 19.
Mr Bradford said he was ‘gutted’ by the theft, adding: “It’s not just a bike. The fact that it’s done so much for me, to help me do so much for Meg.”
When Megan was diagnosed with the disease, which is degenerative and currently has no cure, Mr Bradford lost 11 stone and took up cycling to raise funds towards researching the condition.
His #Miles4Meg fundraising trips have seen him complete three 100-mile rides in London, a tour of Cambridge, a ride to Paris and up Mount Snowdon – raising more than £70,000.
The research funded by his contributions saw a break-through last year, he said, and will hopefully progress to human trials.
Mr Bradford has previously described the disease as ‘devastating’. “The only thing you know is that tomorrow, you will be worse,” he said.
Megan relies on an electric wheelchair and although Mr Bradford said her condition has somewhat plateaued recently, her speech was starting to fade.
Mr Bradford had been planning two further fundraising rides in September and October on his bike, which he bought from Quest Adventure in Broadwater.
But due to so many people taking up cycling during the lockdown, he said: “No one has any bikes for sale.”
Mr Bradford said he had been contacted by people who had been inspired by his fundraising efforts to do something similar.
“It’s amazing, you don’t realise you have that affect,” he said. “It’s all quite humbling.”
To support his fundraising, visit his justgiving page here.
Anyone with information about the stolen bike should call 101.