Involution is a moderate-difficulty single track that descends from the top of Barnicoat Range into Marsden Valley, passing through native bush the whole way. Opened in 2010, its construction was a collaborative effort between DOC, Nelson City Council, Nelson Mountain Bike Club and the Department of Corrections.
All Barnicoat Range and Marsden Valley trails can be accessed off the end of Marsden Valley Road, 5 min from Stoke. At the end of Marsden Valley Road, just before the quarry, there is a small car park on the right. Here you will find an information panel with a map and details on trail times and distances. There is also plenty of room to park alongside the road.
The uphill end of Involution starts off Jenkins Hill Road, at 715 m elevation. The most straight-forward way to reach the start of Involution is via the Glider Road and Widdershins. Combining the latter two trails with Involution provides a solid 11.5 km loop route from Marsden Valley. The start of Involution is well-signposted.
Involution has a technical rating of moderate, though aside from negotiating a few rocks and roots and some tight turns, the track shouldn’t pose too much of a challenge for less-experienced riders.
Involution descends gently through beech forest off the top of the ridge. Further down the track goes through a series of tight zig-zags on the southwestern slopes of Jenkins Hill, and the surrounding bush becomes more of a broadleaf mix. The track rounds the heads of a couple of lush gullies, crossing small streams in each. The track again descends through a series of sweeping zig-zags, and the surrounding bush again transitions to kānuka.
The bottom of Involution links up with the Old Weir Track; follow this for 500 m back to Marsden Valley Road.
Whilst it is predominantly used for mountain biking in the downhill direction, it can also be completed in either direction on foot. For those enduring the uphill grind, the native bush and winding track provide more interesting surrounds and a gentler gradient than nearby Glider Road (just be cautious of mountain bikers coming down).