Likes Bikes and Dirt
These are probably questions for Steve. No harm in being a cynic, I usually am as well. However, I have a friend who is very close to Steve, and knowing how incredibly switched on he is about this stuff I'm happy to take his graphs and testing on face value.Missed my point, they are not using the same sag point, assume the sag point is 25% then the shock displacement should be the same for either shock at that point. Once you adjust for that the curves beyond the sag point are pretty much exactly the same. The way it is presented is not an apples and apples comparison.
Thinking about it more the thing that interests me is the graph, Vorsprung say "However, a particular standard Fox air spring curve has a spring rate that drops by more than 90% from the beginning of the stroke..."
So is it just one model or all models that exhibits this behavior? One example or all examples? Or one cycle or thousands of cycles on a shock dyno? If it is just one cycle that is a very different thing compared to use where the shock is constantly moving. Is it a stiction thing? Does it occur if you start the stroke from the sag point instead of zero? I am too cynical to believe one graph without questioning...
I'm not arguing suspension systems (I have both DW and VPP bikes), I agree that a falling rate at the start of travel is counter intuitive but I also find the falling rate of an Ironhorse Sunday over the last 40% of its travel counter intuitive :noidea: but hey they are a great bike and ride well and at the end of the day that is what counts.
I don't get the 'high initial spring rate of an air shock' I reckon that is BS. Air shocks increase in pressure as they compress as a result of the volume reducing and as a result the spring rate increases, the Vorsprung graph makes no sense to me with the really high spring rate at the begining (hence my previous question - if it a single cycle then stiction would play a big part in the readings). The graph below shows DB air with different air cans and the effect they have on spring rate, I know there are no numbers but it makes more sense.
View attachment 308863