The longest-travel version of Bionicon’s adjustable-travel bike range, Ironwood proves the system’s versatility with capable descending and acceptable climbing.
Bionicon has addressed the issue of big travel bikes suffering on the climbs and short travel bikes feeling squirrelly on the downhills, by developing an air swap system that enables you to radically alter the bike’s geometry on-the-ﬂy.
Bionicon needed a frame platform to demonstrate the technology though, and so Bionicon bikes were born. There are various models, from cross-country bikes to the ﬂagship Ironwood 200mm (8in) travel all-mountain monster.
Ride & handling: steady climber, downhill sled
When a mountain goat climbs it straightens its rear legs and tucks in the front to keep weight low on the hill. When it goes downhill, the front legs will extend and the rear compress to offer the exact opposite. And this is how the Ironwood works.
The concept of the adjustable geometry is brilliant, although there is limited use for people in the UK. It’s really designed for the Alps, where slow and steady climbs are rewarded with amazing downhill riding.
However, the bike climbs admirably, despite its 38lb weight. It’ll never be a fast mover, but for people who want all their fun downhill and on the drops, this bike could be an ideal solution. Downhill, of course, compares to riding a light downhill bike.
Frame: single-pivot long-travel simplicity
The Ironwood is designed to be the fastest bike down the hill that can actually get up the hill in the ﬁrst place – essentially the mother of all-mountain bikes. Its 8in of travel hang from a burly looking frame that builds to a 17kg (38lb) complete weight, which is light for such a big travel bike.
A simple single pivot sits just below the chainline, promising minimal bob and decent performance. The cantilever style swingarm uses conventional dropouts for quick release hubs and a custom X-Fusion shock – including the slave air unit.
Components: keeping the weight under control
The Ironwood doesn’t have a burly spec. It rolls on lightweight Alex rims on Schwalbe Big Betty tyres, while a mix of SRAM X-7 and X-9 sorts out the transmission.
Out back is the plush X-Fusion 02 RPV shock with a 60mm stroke, delivering 203mm (8in) of travel at the wheel. On top of the shock body is the slave air unit, which allows air to be swapped from here to the fork. This slave unit doesn’t alter the amount of travel – it simply alters the ride height of the rear end.
Up front is the Special Agent fork, with 203mm (8in) of travel and a unique 35mm axle for stiff steering response and rapid wheel removal. On top of the left fork leg is a valve to allow air from the fork to supply the slave unit on the shock, and vice versa. This allows travel to drop to 100mm (4in), altering the head angle from a downhill-friendly 64.5 degree to 71.5 degree, which combines with a 15mm raise at the rear end to give a steeper seat tube angle and a great climbing position.