I'm about to hurtle downhill on a bike from the summit of Mt Tarawera. That's 10km down a 4WD track carved out of a silky and slippery rock that you loll around on rather than stick to. Even though I'm fitted out in armour, with knee and elbow pads, shin and chest guards, and the obligatory helmet and gloves, it's still a little unnerving. It will be my fastest downhill.

We bumped and bounced our way slowly up the road to the summit in a Hilux and crikey, it's steep.

I know what you're thinking. You got a ride up? Well, when you've got a weekend in Rotorua - a mountain biker's mecca - time is precious and thrill-seeking comes first. Besides, it's Sunday afternoon and I'm heading home to Auckland in three hours or so. That leaves just enough time to wander round the top of this sacred mountain, explore the eerie crater and then scorch down its beautiful slopes.

This volcano, which last erupted in 1886, killing 153 people and destroying the Pink and White Terraces, is sacred to the Ngati Rangitihi people, who own it. And, as Nick Chater, my guide today from Multi-Day Adventures, says, it's a special place to start a mountain bike ride from.