Here is the opinion of C. Sharper from London who has rented a Magnum Ui5 bike to visit Waiheke island with his partner, seen on TripAdvisor:
"My partner and I travelled across Waiheke on Darleen's e-bikes in September and it's definitely one of the highlights of our trip so far. At first the speed of the bike may seem daunting up, but you quickly appreciate it when you power up some of the island's biggest hills. Make sure to visit some wineries and do a hike too. This was an awesome experience that I would recommend to anyone."
You can also easily rent a bike in Waiheke at EcyclesNZ Bike Rentals and bring it back in Newmarket at Bikes & Barbers !
This post is also on Bikes & Barbers' Wordpress Blog.