Dahon Handleposts-Who can explain the Hinge Clamp?
(Note: This is a repeat of a portion of my last post in the "Dahon chop shop (bars)" thread, which has not had any follow up since yesterday. The post dealt with a couple of issues but ended with several questions relating to the Dahon handlepost. I would like to understand this critical part of the Dahon folder, so I am starting a new thread on the subject.)
I have a late model Dahon Boardwalk with a "Revolve" (I think) handlepost. The handlepost is simply a long riser and stem. As all Dahon users would know, the handlepost has a large hinge just above where it attaches to the bike's fork. The hinge allows the post to be folded about 180 degrees, from a nearly straight up position to a nearly straight down position. Along with the main frame hinge, the folding handlepost is at the heart of what makes the Dahon a folding bike.
When the handlepost is in the "up" or riding position, it is held snuggly in place by a multipiece clamp device. For reasons I can't fully explain, I am not thrilled with the hinge clamp design. What bothers me, I guess, is that the clamp does not make use of a “positive” interlocking system, but, rather, as best as I can tell, a few small metal rods that effectively push the handlepost closed and hold it closed using compressive force (via the small rods). There is a plastic safety catch which prevents the clamp from opening, but the actual stresses are being borne, it seems to me, by some rather small parts.
Here are some questions: I’d love to hear from anyone who has some background knowledge on the subject.
- Are all of the current (say, 2004 and 2005) Dahon handlepost hinge clamps designed in essentially the same way?
- If not, does the clamp technology improve or become more robust on more expensive models?
- Can anyone list the different current models of handlepost?
- Does anyone know why the hinge clamp is designed this way? Would it not be better to have some sort of interlocking device, such as a claw or hook that grabs a notch or a bar, rather than a collection of small push rods?
- Finally, in order to reduce the reach of the bike (i.e., the horizontal distance between the handlebar and the saddle) by about 1 inch., I have loosened the main binder bolt, rotated the handlepost 180 degrees in the steerer tube and retightened the binder bolt. This means that the handlepost now folds forward to the right side of the bike, rather than back to the left side of the bike. Is this OK? Is stress raised on the hinge clamp?
(By the way, I have observed that some Dahon handlepost models allow for an adjustable stem height and use a fairly standard quick-release type clamp to tighten the stem. This part of the design is not the focus of my concern.)
Any thoughts or insight would be appreciated. Thanks.