Cannondale have always done things differently. They have never simply accepted the conventional logic, preferring to walk their own path for bike design. At their team camp in Finale Ligure in Northern Italy last month they had this beauty of a downhill bike out on display - David Vasquez's World Cup downhill race bike, circa 1998. Identical bikes were also piloted by Missy Giove and Anne-Caroline Chausson. The engineers behind this bike were clearly pushing the envelope of what was known and possible with these bikes, it also shows how far bike design has come since then in some ways, and hasn't changed much at all in others. We take a closer look...
First off: geometry. That's pretty slack and the chainstays looks pretty short, but for a modern bike that BB is way high. And yes, it's not what you'd call light.
What the hell? That's the first thing people usually say when they see the crank/drive arrangement. Like everything Cannondale did with this bike, there's a reason for it though and a singularity of focus you don't find too often. Look at those linkages for the suspension, do they look familiar? They should, as Santa Cruz and Intense (who license the design from Santa Cruz
) use a variation of them for their VPP bikes today. Cannondale's engineers optimised the linkage to work with a specific chairing size, a larger or smaller ring would affect the performance, but their racers still wanted to be able to change their gear ratios to suit different courses, so this system was developed to keep that size constant.
There are five rings in all, but it is the ring on the non-drive side crank that drives the system, in the same way that the chainring(s) do on the bike sitting there in your garage. That power is then transferred by the first chain up to the sprocket sitting forwards and above it. A fixed axle transfers that power through to the sprocket on the driveside and a chain connects that to another sprocket sitting behind the larger driveside chainring. There is then a system similar to a freehub engagement to turn the main chainring as it is not directly attached to the crank arm. To adjust the gear ratios the team mechanics could change the size of those four sprockets driving the chainring - although it wasn't too popular with them as it was so complicated.
The "Super Downhill Moto Fork." What a name. Essentially it is two modern Lefty forks, bolted together at the crown.That means each leg has a complete, separate damping system. You can't see it because of the boots, but they don't use a round tube, like modern stanchions, instead they are square and use needle bearings instead of bushings. For this length of fork, Cannondale felt that the twisting forces from compression and braking compromised the kind of bushings every major manufacturer uses today and meant a loss of performance. This system of square tubing and needle bearings completely separates the vertical movement of the fork from the forces acting on it.
The idea of adjusting geometry at the headtube is nothing new - here you can see offsets in the headtube to help slacken out that headangle. They are custom-machined eccentric cups for the headset bearings to sit in to give a couple of degrees of adjustment. It's also worth noting the size of that headtube - Cannondale invented the 1.5" headtube as they realised the larger area meant they could build their frames much stronger. On this bike the fork uses a 1 1/8" steerer, which gave them the room for the offsets.
While some of the bike was well ahead of its time - the rear axle still had some way to go, as nobody had started using burly through axles at this time - that came with the next generation of their bikes.www.cannondale.com