A gorgeous view combined with a narrow pathway winding around the Ohinemuri could leave you in danger of toppling into its brisk waters - a problem easily rectified by getting off the bike.
The second moment also requires some tunnel vision - literally.
Carved out of solid rock and lined with 1 million bricks, the Karangahake Rail Tunnel stretches more than 1.1km and if you are caught without a torch the ride can be a little unnerving.
But, as they say, there's light at the end of it and also a nice open ride to the cafe at Waikino station, where you can fuel up and either take the vintage train ride to Waihi or bike the 11km to the town.
At the end of the ride we head to Te Aroha for a soak in mineral spas.
Once the country's focal point for such activities, Te Aroha is now dwarfed by the tourist town of Rotorua and is a much more laidback experience.
Also worth a visit there is Historic Creations, a design studio created by local artist Adrian Worsley. The life-size sculptures made from locally sourced scrap metal, tools and farm implements are arresting and it is no surprise Worsley's work has drawn a cult following.
The next day, we ride onwards to Hamilton and take on part of the Te Awa trail, a more urban ride on the banks of the Waikato. A trail will soon link onwards from Hamilton so you'll be able ride all 85km from Ngaruawahia to Horahora.
CHECKLIST
If you go playing there
Eight distinct cycling regions on the New Zealand North Island are set out brilliantly on the recently launched website: www.ridenz.co
Ability required, trail status, accommodation and dining options, hire stores and all the information you'd need for a bike trip are explained. Auckland is the best starting city for your trip.
