I have acquired two new 9FSs in the past two weeks. I spent a lot of time researching folders and the Downtubes seemed to be the best bang for the buck. Now that I have had them and ridden them I can say that I am very pleased with the choice. Great value.

The one feature that is missing, in my view, is mechanical "keying" of the handle bar stem to the base tube. Every time I adjusted the handle bar height it took me several tries to get the bars perfectly square to the front wheel.

The Dahon folders have a design feature for doing this. I decided to add a few small parts to achieve this function on my DT. I have installed this mod on both bikes and it is working very well.

If you are curious, I have posted a small group of photos of the mod on my photography site. This will take you straight to the gallery, or you can get there from my website, imagesbypyarnall under "Pages". https://www.imagesbypyarnall.com/ibpy.../downtubestem/

Contact me if you would like more details. I now consider it an added layer of safety in case the clamp is accidentally released while riding, though that seems admittedly unlikely.

P Yarnall

Nice but...wouldn't a line with a Sharpie marker have been a lot easier? That's what I do with my seatpost.

Easier than what? I can tolerate a slight misalignment in the seat with respect to the frame, but not the handle bars. When I use the bikes around home I might not change anything for weeks, but I also take them with me on camping outings. In that setting the bikes might be folded and unfolded several times a day. Getting the handle bars square on two bikes after every set up was a real annoyance. The mere act of securing the stem clamp which adds a torque reaction to the front end, in turn resisted by trying to wedge the front wheel between your knees usually resulted in several tries to get things "square". Add to that the occasional height change and the realigning process had to be repeated. Drove me nuts.

In addition to keeping the handle bar stem aligned, it also adds a safety feature..... if the clamp comes loose I do not loose the ability to steer the bike.

In any event, since I have a design and prototyping background, I am accustomed to fixing or improving what ever is in front of me. For me, this was clearly a problem that needed fixing. If it is not a problem for you then it does not need fixing. I posted my efforts to suggest a possible solution to others who might share my annoyance at the lack of an alignment feature..... a feature found in many other folders.

nice mod.
I had that sort of problem with my dahon, where if I put down enough power, I would twist the bar alignment.

Nice mod, but now you can't rotate the handlebars sideways. I find this ability almost as convenient/important as being able to fold the frame in half.

Chucky, I overcome that issue by simply pulling the handle bar stem all the way off the base tube when folding and just nestle the handle bar assembly into the folded assembly. When traveling the bikes are usually on a hitch platform which has only a limited amount of clearance to the slide in camper just above it, (camper extends past the bed of the truck). With the handle bar and stem completely withdrawn from the stem I can get the whole package height further reduced. Admittedly it adds (literally) a few seconds to the set up but that is more than offset by not having the alignment hassle.

That won't work for me because I still need the sideways (unfolded) bars to roll the bike around (whether the frame is folded or unfolded). I also hook the sideways (unfolded) bars over my shoulder and carry the folded bike under arm.

I'm sure it's a great mod for some people, but I think I'll continue aligning my bars by bracing the wheel against the straight of my foot.

Nice mod. Reminds me of some of the mods I have done over the years.

Suggestion: Shortening the square rod will allow you to rotate the bars by pulling the stem up just a little way.