(Note: some of the following repeats what I have already posted in the (other) Dahon Boardwalk Chopshop thread, so I apologize, but the subject leads me to a few Dahon handlepost issues that I want to highlight in this posting, as I would really appreciate seeing some feedback on these handleposts.)
Regarding the use of drop bars, I will say that folding my bike compactly is not a priority for me: having a bike that I can ride is. I can't stand straight bars and I have been riding drops since the 1970s, so, along with the 3-piece bottom bracket, the straight bar on my new Boardwalk was quick to go.
The first obstacle was the handlepost (i.e., the combined riser and stem that goes from the fork steerer tube to the handlebar). My Boardwalk (2003 or 2004, not sure which) came with a fixed-height handlepost that was so high it seemed only suited to very tall person (or a large meercat) and not an average size rider (say, 5ft.6 to 5ft.11). In order to mount drop bars in a traditional touring position (i.e., at more or less saddle height), in my case the handlepost would need to be at least 3 inches shorter.
Dahon makes an adjustable post (about $40) but it was not available in mid-April when I tried to order it, and I was anxious to get the bike on the road. Moreover, I didn't really want to spend the $40 if there was a cheaper and more resourceful alternative.
As I had an 1 1/8 in. Aheadset quill adapter and a short alloy stem in my parts collection, it occurred to me to chop (literally) the tapered steel handlepost at the point where the inner diameter of the handlepost was the same as the quill adapter (1 in. or 25.4mm). It turned out that this was about 2.5 to 3 shorter than the stock handlepost, so it worked out well. Using a short, sharply angled stem upside down took the bars even lower (Also, since I had these parts on hand, the cheapness test was satisfied. If you had to buy these parts, you might be better off ordering the adjustable handlepost).
The related other issue for the "less-than-tall" rider is the reach on the Boardwalk. It's a pretty long stretch. The saddle can be pushed forward an inch or so, but any kind of stem with forward throw will take smaller and mid-size riders too far forward (the stock handlepost has no throw: just a clamp at the top for the bars). I dealt with this in two ways:
First, as already noted, I used a very short throw, steeply angled stem (mounted upside down). This gives 2.5 in. of drop and only 2 in. of throw. It looks a little odd, but it works.
Second (and this is really the point of this entry), I rotated the handlepost 180 degrees in the fork's head tube. This has two effects:
A. The overall reach is reduced by about 1 in. because the handlepost does not rise perpendicularly from the steerer tube, but rather at a shallow angle. When turned 180 degrees, the top of the handlepost moves rearward toward the saddle; and
B. As regards folding, it caused the handlepost (and attached bars) to fold to the outside of the folded bike. This means that the awkward shape of the drop bars does not prevent the front and rear portions of the frame from coming together when folded. With the handlepost folded, the drop bars do jut out of the side in a slightly strange way but this can be minimized by loosening the handlebar clamp and rotating the bars a little (and, if need be, feeding one handlebar butt into the front wheel spokes).
It's not as neat or as quick as the stock set up, but it's still small and easy to store on a closet or back seat of a car. It might make it harder to store in a small car trunk or on a train, as it's not as squared off as the stock set up. It would be nice to have a quick-release lever on the handlebar clamp, but, again, in my case folding is not a priority.
This conversion project has gotten me interested in the design of Dahon handleposts.
I am not thrilled with the hinge clamp design, which does not seem to make use of a “positive” interlocking system, but, rather, a few small metal rods that effectively push the handlepost closed and hold it closed using compressive force (via the small rods). 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 on more expensive models? (I think that mine is a "Revolve" handlepost)
- Does anyone know why the clamp is designed this way? (It seems to me that it would 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, am I risking anything by rotating the handlepost 180 degrees in the steerer tube? Is stress raised on the hinge clamp? (With the post rotated, if the clamp fails, the bars can fold forward (and to the side). In the stock position, they can fold backward (and to the side). Both scenarios seem bad to me, but if one is better than the other, I’d be curious to hear it.)