“It’s all difficult to quantify, especially stiffness”
Not really, it’s a pretty well defined engineering term. Stiffness can be defined, measured, designed, modelled etc. They are a lot stiffer though (lefty’s). The double crown plus the square sanction and needle roller bearings. They perform better too due to lack of stiction due to roller bearings rather than bushes and it is noticeable, both in terms of stiffness and more active suspension under braking. My Pikes feel well noodley compared to my old Lefty.
They do present problems though and are more costly than other forks so not sure many other manufacturers will be queuing up to make them. Shame though because after being a Cannondale only piece of kit for all these years with no competition the R&D has been very slow and stilted. If other manufactures were to make Lefty’s then they’ve get a lot better very quickly.
I’d have another Lefty in a heart beat but seems like C’dale are no longer offering them in anything but their short travel and more XC orientated bikes.