"It was my second job and I thought 'this will do for a while"'.
However, it was the start of a life-long passion.
"It's addictive and I want to share that with others. I'm planning to start workshops so I can teach others how to build their own frames," he said.
Mr Pearson is a competitive cyclist and started building frames in the late 1970s in search of a fast, lightweight race bike for himself.
"I was about 18 when I made my first bike from aluminium and started winning races on it.
"I love building things, trying out new ideas and making better products, not just bikes, but wheelchairs too."
Mr Pearson now builds his high-tech road bikes in carbon fibre. "I'm into composites and aerodynamics. You can make a bike out of any sort of material and it will give certain qualities, but to make it as light, stiff and aerodynamic as possible, carbon is the only material," he said.
Along with bike frames and new technology, visitors to the expo can expect to see a great range of clothing and bike accessories, nutrition, bike history displays and vintage bike collections.
Registration for coming events can also be made at the expo. Two of the more unusual bikes on show will be Red Stag Timber's Red Stag Renovo Bad Ash 29er - a bike made from radiata pine - and Gisborne's Freddy Salgado, who builds bikes out of bamboo.
The Kiwi-Puerto Rican was a legend in California before moving to New Zealand in 2004.
He was the first to build bikes in carbon fibre and continues to innovate with materials like hemp and bamboo.
Visit www.rotoruabikefestival.com