New Christchurch invention lets cyclists electrify bikes they already own

Sunday, 21 June 2026

Duo co-owner James Zwaagman says installing his company’s e-bike system is as “simple as fitting a wheel set'.

After selling thousands of e-bikes across New Zealand, three Christchurch entrepreneurs noticed many cyclists wanted electric assistance without giving up the bikes they’ve spent years perfecting.

James Zwaagman, Dave Comerford and Brad Mitchell are the trio behind behind Duo, a lightweight electric wheelset that turns a standard road or gravel bike into an e-bike.

The wheelset, weighing roughly 2.5 to 3kg, includes a rear carbon wheel with an integrated 250-watt motor and a matching front carbon wheel cyclists can fit themselves.

Zwaagman and colleague Dave Comerford run Wattwheels, which help Nuk Korako, centre, with his month-long mission to bike from Perth to Melbourne to raise money for Child Cancer NZ and Australia last year.

Zwaagman said Duo has been in the works for almost two years, established after “seeing the same problem over and over again” in the bike industry.

“A lot of people still love cycling, but maybe the hills are getting harder, they don’t have as much time to train, they’re coming back from injury,” he said.

Created by Wattwheels, one of New Zealand’s largest locally owned e-bike companies, the Duo wheelset is targeted at active road and gravel cyclists seeking further enjoyment and assistance for “recreational riding, longer rides, [and] hills”.

Both road and gravel wheel options are available.

The wheelset’s bottle cage-mounted battery takes about 2.5 hours to charge, has a range of about 55 to 70km on flat terrain and 25 to 35km on hilly terrain, and is capable of speeds of more than 40kph.

To “comply with local laws and regulations”, the maximum assisted speed will be limited where required.

Zwaagman believes they are the first company in New Zealand to develop a product like Duo, and said there’s little international competition too.

Comerford, left, Zwaagman, Brad Mitchell, and Karyn Gibson created Duo for those who are “looking to get more enjoyment from their riding', Zwaagman says.

The Duo wheelset kit - including the two wheels, battery, smart charger, and carry bag - is expected to retail for about €2000 (NZ$3900) internationally. The average price of an e-bike in New Zealand is $3500 to $5500, with cheaper and more expensive options available.

But Zwaagman said the advantage to Duo was that it let riders modify the bike they already have, rather than buying something completely new.

“They’ve often spent years building up a road or gravel bike they love… It’s the same bike, same fit, same riding position … just with electric assistance there when you want it.”

Zwaagman has worked in the bike industry for more than 20 years and has been riding and racing bikes for most of his life - “from road racing and track cycling through to mountain biking and cyclocross” (a form of racing).

His experience building and selling thousands of e-bikes across New Zealand over the past decade sparked his interest in exploring a “different solution for cyclists”.

Also under development is a companion app so riders can “fine tune the assistance levels” to suit their cycling style and needs.

Zwaagman said much of Duo’s testing has been done on Canterbury roads, gravel routes and climbs, and the response so far has been “incredibly positive”.

The company has partnered with some of the “biggest and most technically capable manufacturers” in the cycling and e-bike space and recently showcased Duo at Eurobike - a global cycling trade fair in Frankfurt, Germany.

“We’ve had interest from riders throughout New Zealand as well as overseas with the most interest coming from Italy, Spain and France,” Zwaagman said.

Duo is now in the final stages of testing and product preparation, and is expected to launch in the next two or three months.