You can pretty much generalize here, the shorter the steering lever, the less it will flex... materials being similar, a long telescoping post will flex substantially more than it's shorter counterparts.. the bikes without a folding steering lever will usually be stiffer again .. The Swift is comparatively stiff (but due to its rather long lever) will not be quite as stiff as the Pacific Reach, the TSR Moultons, Airnimals, and the like with less lever above the headtube bearing .. in a folding post, the Birdy (left short) is one of the best.. Dahon's one piece short handleposts (like on some Jetstreams) are also good....