Rock Shox's advertising for the new RS-1 upside-down fork claims "There's no such thing as can't." This new fork is intended to dispel prejudices against upside-down forks, such as a lack of steering precision and excessive weight, once and for all.
Thanks to innovative detail solutions, the RS-1 is intended to improve riding efficiency and increase the response behaviour to small impacts to previously unimagined heights. In addition, the one-piece carbon upper section consisting of steerer tube, fork crown and stanchions as well as a hub specially adapted to the fork should ensure sufficient stiffness in every situation.
But why upside-down? In theory, the following points speak in favour of this fork design:
1. the unsprung mass is lower, which means that the fork can react more quickly to subtleties.
2. the inverted design means that the seals are always lubricated with oil and do not run dry. The fork can respond more sensitively.
3. the one-piece construction of the upper section means that the brake rigidity is very high. Even when braking, the fork tilts less and remains active.
In order to verify Rock Shox's promises, we subjected the fork to extensive riding tests and, of course, analysed it in our test laboratory. The result: at 120 millimetres in length, the RS-1 weighs 1704 grams. At 240.9 Nm/°, the RS-1 also achieves an extremely high braking stiffness. A SID World Cup with 100 millimetres of travel only achieves a value of 176.2 Nm/°. In terms of torsional rigidity, i.e. steering precision, things look worse for the RS-1. At 12.7 Nm/° compared to 25.1 Nm/°, the RS-1 is significantly softer than the 100 mm SID Worldcup.
In the September issue of BIKE, you can find out how these measured values make themselves felt in practice and what other technical highlights the new RS-1 has to offer in the innovation check. BIKE 9/14, on newsstands from 5 August!
