World Champs is always a special race where teams and sponsors go all out to give their riders any and all advantages possible, and because of that it is also the setting where we see a number of projects debuted that have clearly been in the works for quite awhile. This year's venue at Pietermaritzburg, South Africa, is no different, with the relatively smooth track likely making for some very special setups - we expect riders to be on anything from full-out downhill race bikes to six inch travel all-mountain rigs come race time. Two riders who we anticipate will choose to ride the former, though, are Trek World Racing's Brook McDonald and the Syndicate's Greg Minnaar, with Brook's Session 9.9 and Greg's V10 sporting very special FOX shocks that are products of FOX's RAD (Racing Application Development
The RAD program has been responsible for a number of the products that we first saw on the bikes of very select World Cup racers, with some of them eventually hitting production - the current DHX RC4 shock, for example - and others not making the cut - a la the prototype inverted DH fork that was eventually cancelled. While FOX declined to comment on the unnamed shock, it is clear that it looks nothing like a DHX RC4, with some major differences that set it apart, most notably the shock's wildly different adjuster dials and steel shaft. Although we are forced to speculate at this point, there appear to be four separate dials, with stacked compression and rebound knobs that control both low and high-speed damping. The anodized red dial likely controls the low-speed rebound, with the large hollow nut above it being used to alter the high-speed rebound setting. We're guessing that the same can be said of the anodized blue compression adjusters right next to it, making this prototype RAD shock a four-way adjustable unit that likely uses completely separate circuits for compression and rebound damping duties. This is supported by what appears to be two plugs just below each dial that would give FOX access to each of the circuit's respective check valves. Again, this is pure speculation at this point, but it would make sense that FOX would pursue a shock design that allows for more external tuning. While the current DHX RC4 uses a large blue dial at the end of its piggyback to adjust its volume, this prototype shock appears to make use of a much
more svelte system that probably accomplishes the same task. Much like a fork's preload adjuster, this new dial looks to sit flush with the piggyback body, with internal threads that likely move the position of a volume-changing puck, allowing the rider to adjust how the shock ramps up. The layout looks much more discreet than what is currently offered from FOX, and it is probably lighter to boot.
The other major talking point is the shock's much smaller shaft that appears to be steel opposed to the larger diameter aluminum version used on the standard DHX RC4. The shaft's smaller diameter means that it will displace less oil than a larger diameter version, making for less ramp up throughout the shock's stroke. The other upside to the smaller diameter shaft would be its smaller swept seal area that would help lessen friction, especially breakaway force at the top and bottom of its stroke, as well as when it changes direction from compression to rebound. It is plausible that none of the above would have been possible with an aluminum shaft due to it being too fragile in a decreased diameter.
As expected, there will be a number of top riders who will run an air-sprung rear shock instead of either a DHX RC4 or the prototype coil-sprung shock discussed above, and it appears that it will be the RAD air shock that was tested during practice for the Fort William World Cup
. While it certainly resembles a DHX Air shock (which is no longer listed on FOX's website, by the way
), it is safe to say that it likely employs some of the design features of the promising Float X shock of FOX debuted a few months back. With much of the above being only theory at this point, it will be interesting to hear FOX's official word on both the prototype RAD coil and air shocks shown here.Stay tuned for more from South Africawww.ridefox.comPhotos by Matthew DeLorme