Thorn is the house brand of St John Street Cycles, and the house specialty is touring bikes and Rohloff hubs. The Raven Sterling is pitched as a do-it-all alternative to the Raven Enduro (enduro hardtail) and Catalyst (touring mountain bike). The many spec choices let you slide it up and down that enduro/expedition scale.
The ride: hard working hub gear
When you’re mountain biking on a bike with a Rohloff hub, you’re in gears 1-7 a lot. This means, unfortunately, that on hilly singletrack the bulk of your riding is in the hub’s less efficient gears (see below). If you had a 2×7-speed hub that stepped up instead of down (and was strong enough not to explode with the torque going through it), you’d be in the quiet gears when climbing and in the less efficient gears when cranking along at speed – a better compromise.
For now, you could rip up Rohloff’s warranty, which tells you not to use a ratio smaller than 2.35 to 1, and run 34×17 instead of 40×16. That would put gears 8-14 in mountain biking’s sweet spot, with direct drive a 2:1 ratio.
Like the Alfine, the Rohloff has advantages over derailleurs – but the German hub is tried and tested off-road. It’s been around for years and has proved to be practically indestructible. The hub isn’t heavier than some derailleur setups, and having it all in one lump doesn’t seem to detract from the handling. Climbing is laborious, but that’s down to whirring pinions rather than weight. Descending, the Sterling holds its line well.
Frame: custom chromoly, fittings for everything
The frame is ‘Thorn 858’, a custom chromoly tubeset with Reynolds 853 for the main tubes and ‘more resilient’ seat stays. There are frame fittings for everything, even V-brakes. An eccentric bottom bracket tensions the chain, while the dropouts are Rohloff-specific. The left one is deeply socketed to accept a short torque arm so that, unlike most hub gears, the rear wheel is quick-release.
Equipment: heart of Rohloff
The Rohloff hub has 14 evenly spaced gears, with a similar range to a derailleur set-up. Ratios are: 0.28, 0.32, 0.36, 0.41, 0.46, 0.53, 0.6, 0.68, 0.78, 0.88, 1, 1.14, 1.29, and 1.47. Like the Alfine hub on the Genesis, it doesn’t like shifting under heavy load – especially between seventh and eighth.
It’s essentially a seven-speed hub (gears 8-14) with a reduction gear for gears 1-7. That’s why gear 11 is direct drive and why gears 1-7 are noisier and less efficient than 8-14: you’re getting drive at the bottom end through an extra set of internal gears, with the extra frictional losses which that implies.
The Magura Odur coil-sprung fork feels firm and imperturbable. Its dual-arch design means it tracks solidly, and it feels as if you can fit it and forget it. You can adjust the rebound and limit the travel with a dynamic lockout; other adjustments require you to faff about with spacers and different springs.
A long stem and narrow ﬂat bar feels old-school cross-country. It’s fine for all-day riding on dirt tracks, but a shorter and wider bar would better suit technical singletrack.