Upside-down forks have long since become the norm on motorbikes. In the mountain bike sector, this type of suspension fork has never made the breakthrough and has been relegated to a shadowy existence on a few downhill bikes. However, from a purely technical point of view, upside-down forks have a number of design-related advantages over classic telescopic suspension forks:
- More stability, as the large diameter outer tubes are at the top.
- Less unsprung mass, as the lower tubes of an upside-down fork are light
- Less susceptible to dirt, as the inner tubes protrude downwards from the stanchions. This allows dirt and water to run downwards.
- Perfect lubrication, as the fork tubes (bushings and seals) are lubricated every time the fork is compressed.
Thicker downtubes than a Fox 40 at only 1870 grams
The steplessly lowerable German A "Revo" is available in 160 and 180 millimetre versions. An oval, teardrop-shaped tube profile prevents the fork tubes from twisting. With this guide, the "Revo" outshines all other upside-down forks in terms of stiffness. It is said to be 80 per cent stiffer and therefore almost as torsionally stiff as classic telescopic forks. At 41 millimetres, the fork tubes are thicker than those of a Fox 40 downhill fork. The prototype of the "Revo SC" (160 millimetres) weighs 1870 grams, the series fork should be available from spring 2014.
