Martyn Ashton, 41, from Margam, Neath Port Talbot, had set out to raise about £7,000 for rehabilitation equipment.
Friends suggested he set up a crowd funding page rather than sell his Colnago C59 bike worth £7,000.
He described people's generosity as humbling and touching.
Mr Ashton was a professional stunt cyclist, with his videos Road Bike Party and Road Bike Party 2 gaining more than 28 million views between them on YouTube.
But he lost the use of his legs in an accident during a live show in 2013.
He said equipment for people with disabilities could prove expensive so the money would be put to good use.
"I never, ever thought it would reach £50,000," he said. "I can now think long term. It's a remarkable thing."

Just over 60% of voters taking part in the referendum backed the controversial pact, which is aimed at enforcing budget rules in the eurozone.
Prime Minister Enda Kenny said Ireland had sent a "powerful signal" that it was committed to overcoming its economic challenges.
Opinion polls had suggested a "Yes" camp win.
A "No" vote would not have blocked the pact, but it would have barred Ireland from emergency EU funding when its bailout package expires in 2013. In late 2010 Ireland received an EU-IMF bailout worth 85bn euros (Â£68bn; $105bn) after debts overwhelmed its banks.
The treaty must be approved by 12 of 17 Eurozone countries, but Ireland was the only one putting the issue to a public vote.
Speaking after the results came in, Mr Kenny said Ireland had to now work with the EU to boost growth across the eurozone.
"The developing situation in Europe's banking sectors needs a comprehensive solution and Ireland's banking debt must form part of that solution," Mr Kenny told a news conference.
He said the move would not solve all of the country's problems, but that it was "one of the many foundation stones" needed to ensure the future stability of Ireland's economic position.
It would enable investment and create jobs, he said, as well as allow Ireland access to funds from the European Stability Mechanism should it require it.
Returning officer Riona Ni Flanghaile said the "Yes" campaign won by a margin of just over 300,000 votes, with a total of 955,091 casting ballots in favour, compared with 629,088 against the agreement.
Fewer than half the 3.1m registered voters turned out on Thursday, with the percentage ranging from the low 30s in some regions to the mid-50s in some parts of the capital, Dublin.
The dominant parties in the Irish parliament (Dail) were in the "Yes" camp - Fine Gael, Labour and Fianna Fail - while the "No" camp was led by Sinn Fein and the Socialists, who have far fewer seats.
Transport Minister Leo Varadkar said it was a "sigh of relief from the government rather than a celebration".
An Irish 'Yes' but no celebrations
Speaking earlier, "No" voter Gerard Cunningham told the Associated Press: "Banks in Germany and Britain and elsewhere were just as responsible for the mess we're in.
"We're sick to the back teeth of being told it's all our own fault."
Another voter, Bridget Connolly, said she voted "Yes".
"The treaty will solve nothing, but... we're going to need European money next year, plain and simple," she said.
"We can't afford to be thumbing our noses at Europe right now."
The pact, signed by all EU members except the Czech Republic and the UK, allows EU member states to co-ordinate their budget policies and impose penalties on rule-breakers.
It is an inter-governmental agreement, legally binding on all those who ratify it. It is called a "treaty", but is separate from EU-wide treaties which have to be signed by all 27 member states.
It commits all ratifying members to achieve budget deficits of less than 0.5% of economic output.
Last year, Ireland's deficit reached 13.1%.
The country's voters have twice rejected EU treaties - in referendums in 2001 and 2008 - though both votes were overturned in subsequent polls.
Those against the treaty argue that austerity is not working and suggest that the country should instead default on debts at five nationalised banks.
A paralysed stunt cyclist has said he can start planning his own long-term care and rehabilitation after receiving £50,000 in donations since starting an appeal four days ago.
[NEXT_CONCEPT]
Voters in the Republic of Ireland have approved the EU fiscal pact, according to official results.