Chain Reaction Cycles of Ballyclare, near Belfast, made a £13m pre-tax profit in 2010, up from £8m in 2009.
The family-operated business said the the cycle industry is "in good shape" despite difficult circumstances elsewhere in the economy.
In August CRC opened a 10,000-square-foot retail outlet in Belfast, a throwback to the early days of the business, which was founded in 1985 as Ballynure Cycles by George and Janice Watson with a £1500 bank loan.
37 percent of CRC's turnover is generated outside the EU, said a report on BBC.co.uk. CRC is Royal Mail’s largest customer in Northern Ireland; with 35,000 parcels shipped each week.
The Watson family said they can foresee "further substantial improvements" in turnover in 2011, pointing to the the "positive image" of cycling and opportunities in emerging markets.
UPDATE: The retailer has also featured in the Telgraph 'Top 1000', which lists 1,000 mid sized companies that have weathered the economic storm and helped boost the economy. The research was carried out for the paper by innovation promoter NESTA and business information specialist Dun & Bradstreet, as well as a number of other organisations and readers.
CRC’s Michael Cowan said: “Cycling is a strong industry and it’s been said that cycling is the new golf. Chain Reaction Cycles has prospered through recent times by focusing on customer needs, offering unrivalled value for money and quality of service, combined with an international view on e-commerce that has made the UK one of the top places in the world for cyclists to source their bikes, cycle clothing and accessories.”
Dun & Bradstreet UK MD Roger Hodson added: “It is often too easy to concentrate on the negatives – increased business failures, reduced profits, weakened financial strength, lengthened payment terms – and forget that many companies in the UK have faced up to the challenges, and with nimble and brave thinking have put their businesses in a great position to seize the opportunities that exist out there."