Old Fashioned Technology: Cannondale Fulcrum

0


Cannondale has always done things differently. They never simply accepted conventional logic, preferring to go their own way when designing bikes. At their team camp in Finale Ligure in northern Italy last month, they exhibited this beauty of a downhill bike – David Vasquez’s World Cup downhill racing bike, circa 1998 Identical bikes were also ridden by Missy Giove and Anne-Caroline Chausson. The engineers behind this bike were clearly pushing the boundaries of what was known and possible with these bikes, it also shows how much the design of the bike has evolved since then in some respects, and hasn’t changed much at all in any way. others. We take a closer look …

1997 Cannondale Fulcrum

First of all: geometry. It’s pretty soft and the chainstays look pretty short, but for a modern bike this BB is pretty high. And yes, it is not what we call light.

1997 Cannondale Fulcrum

1997 Cannondale Fulcrum

What the hell? It’s the first thing people usually say when they see the crank / drive arrangement. Like everything Cannondale has done with this bike, there’s a reason for that and a peculiarity of focus that you don’t find too often. Check out these suspension linkages, do they sound familiar to you? They should, like Santa Cruz and Intense (which licenses the design of Santa Cruz) now use a variant for their VPP bikes. Cannondale engineers optimized the linkage to work with a specific chair size, a larger or smaller ring would affect performance, but their riders still wanted to be able to change their gear ratios to suit different runs, so this system was developed to keep this size constant.

There are five rings in all, but it’s the crank ring on the opposite side of the drive that drives the system, the same way the chainring (s) do on the bike sitting there in your garage. This power is then transferred by the first chain to the sprocket located forward and above. A fixed axle transfers this power to the drive side sprocket and a chain connects it to another sprocket behind the larger drive side chainring. There is then a system similar to a freewheel engagement to rotate the main chainring because it is not directly attached to the crank arm. To adjust the gear ratios, the mechanics on the team could change the size of those four sprockets driving the chainring – although that wasn’t very popular with them because it was so complicated.

1997 Cannondale Fulcrum

1997 Cannondale Fulcrum

The “Super Downhill Motorcycle Fork”. Which name. These are basically two modern Lefty forks, bolted together at the crown level. This means that each leg has a complete and separate cushioning system. You can’t see it because of the boots, but they don’t use a round tube like modern candlesticks, they are rather square and use needle bearings instead of rings. For this fork length, Cannondale felt that the torsional forces from compression and braking compromised the type of bushings every major manufacturer uses today and meant a loss of performance. This system of square tubes and needle bearings completely separates the vertical movement of the fork from the forces acting on it.

1997 Cannondale Fulcrum

The idea of ​​adjusting the geometry at the head tube is nothing new – here you can see offsets in the head tube to help loosen that head angle. These are custom machined eccentric cups in which the headset bearings can sit to give a few degrees of adjustment. It’s also worth noting the size of this head tube – Cannondale invented the 1.5 “head tube because they realized that the larger area meant they could build their frames much stronger. On this bike, the fork uses a 1 1/8 “steerer tube, which gave them room for offsets.

1997 Cannondale Fulcrum

While some bikes were way ahead of their time – the rear axle still had a way to go, as no one had started using heavy-duty thru axles by then – that came with the next generation of theirs. bikes.

www.cannondale.com


Leave A Reply

Your email address will not be published.