Commencal's current production bike hasn't been on the market for that long, and Rémi Thirion has had some good success aboard a race-tuned version of that very machine. Regardless, the Andorran company has seen fit to develop an entirely new chassis that's nothing like the bike Rémi has been racing on for the past few seasons. That said, the basic suspension layout does harken back to one of the most successful downhill race bikes in the history of the sport, albeit with some more contemporary design cues. Suspension Design
The new 650B wheeled bike, which Commencal is calling the Supreme DH V4, sports 220mm of rear wheel travel via a design that's very different to what the company employed on their last downhill bike, although it is still classified as a single pivot system. An extremely high main pivot is combined with a linkage that's located low on the frame, and there's also an idler pulley mounted inline with the pivot in order to prevent massive amounts of chain growth that would occur otherwise. Commencal is calling the layout 'High Pivot Point', which is pretty self explanatory, and it was first tested on a 160mm travel all-mountain bike to see if they liked how it performed and to fine tune pivot locations.
The V4's high main pivot gives them the rearward axle path that they were looking for: ''Why a high pivot point? To obtain the correct rear wheel path, which avoids stumbling over obstacles and carries a greater speed through rough sections. It goes back to a fundamental concept for downhill - speed.'' As mentioned above, Commencal knew that they needed to employ an idler pulley to route the chain over the main pivot, and they spent some time tinkering with different pulley placements to find the sort of pedalling performance that they wanted, saying ''specifically, by setting the idler on the swing arm in a precise place, we wanted to create an anti-squat value high enough to be lively when needed, out of a corner, for example.''
The 267mm eye-to-eye shock is mounted nearly as low as possible on the frame, and it's compressed via a tidy linkage that is said to provide a very similar feel to Commencal's previous downhill bike, at least in the first 200mm of travel, before supplying a hefty amount of ramp-up in the last 20mm to keep the rider off the bottom of the stroke.
The new V4's geometry is all about adjustability, although Commencal have gone about it in a much cleaner looking way that the usual array of different mounting options and bolts everywhere. They're calling it 'Modular Geometry', and while the bike's head angle is fixed at a slack 62.5 degrees, its reach is adjustable by way of four different offset headset cups that allow for eight possible configurations: -10, -8, -5, 0, +5, +8 and +10mm. The bike's rear center length is also very different from the old bike, with Commencal shortening it up from 447mm on the V3 to 425mm on the V4, and it's also adjustable by using different bolt-on dropouts. However, keep in mind that the 425mm number will grow as the bike goes through its travel, which is something that some racers have found can alter the bike's handling in corners too much for their liking. To this end, Commencal have actually lowered the height of the main pivot compared to what was used on some earlier prototypes, although it's obviously still quite high. It will be interesting to see how their racers, as well as the average rider, get on with Commencal's decision to go with such a high main pivot.