Why did I chose this linkage design?
Over 2 years ago, I was starting my final year of a masters in mechanical engineering degree and had managed to arrange for my thesis to be designing a DH race Bike for Banshee (I knew the Banshee guys already for a summer working with them out in Vancouver).
I wanted to come up with something new, but was not prepared to design an overly complicated linkage that had to use marketing gimmics to sell it (like some bike companies seem to resort to).
Firstly, I took into account all the aspects of the design that I felt were very important for a DH race bike, such as having a high strength and light weight design with a very low centre of gravity, and race geometry with low standover etc..
Once I had sketched loads of different suspension linkage options, I finally settled on this system, as all aspects of the linkage (such as axle path, chain stretch, leverage ratio, force interface, angular rotation of rear triangle, instantanious centre, centre of curvature etc etc) are highly tunable, and with the shock just above the BB, the centre of gravity is very low in the frame.
The next stage was to work out a way of fitting the shock and pivots into the system, this is where I started to design the forged shock basement to not only fit all the parts together, but to do it in a very lightweight and strong way that removed welds for the areas of high stress.
Then it was a case of doing hundereds of linkage itterations to find the pivot and shock mount loactions that would give the best possible suspension characteristics for DH racing, and I also spent a lot of time comparing my linkage performance with many other top DH bike designs to ensure that on paper the legend suspension out preformed them all.
Once I was happy with the linkage (which took 6 months or so of hard work!) I started to do the 3D modeling of the frame with detailed stress anaylsis. again there were a number of design itterations with redesigns to reduce high stress regions and reduce material where there were low stresses to save weight. I also wanted to keep clean lines and simple but efficient aesthetics trhought the frame design.
This has been going on for about 18 months on and off to achieve this model, and once the prototypes are ready, then I am more than prepared to carry on the improvement process to refine the design further with yet more feedback from racers and test riders. By the time the first 50 frames are released to racers around the world the frames should be dialed, but I will still be asking for yet more feedback and ideas to improve the design even more!
We are treating the Legend as an engineering and design project, with the aim to give our riders the best possible tool for the job. We ae not going to be making money on the Legend as it is costing us a lot to manufacture and develop. People might find this weird, but personally I believe that the flagship model of any company represents the whole brand. And as we are a 'new' Banshee, we have to show people how our design ethic has changed, and preformance has improved to meet and exceed the customers expectations.
