Originally Posted by Duragrouch

I disagree with the above. I had that exact bike, serial number indicates 2005.

The stem you have is MORE rigid, it is one piece, tapered chrome-moly steel, and well braced at the base. The later *telescoping* (height adjustable) stems have a good base of forged aluminum, but the telescoping clamp joint at the upper (smaller diameter) stem section is where you will get more lateral flex. This is why (I think) the Dahon Speed TR (touring) used the old stem, because with touring loads, handlebar forces when climbing will be greater. The rigid stem is the same height as the telescoping stem when all the way up, so if you like your handlebars in that position, the telescoping stem is no advantage, except if you have clip-on aero-bars, when swiveled up to fold, those can drag on ground when folded, unless you can shorten your stem to compensate.

Misalignment of handlebars is easily corrected; Loosen clamp bolt at base of handlebar stem, realign, tighten. Perceived looseness at handlbars, rocking, can also be loose heaset adjustment; Fold handbar stem, loosen clamp bolt at base as noted above, *barely* tighten very large center bolt above head tube (I think 10mm? allen), only enough to take out slack, overtightening will brinell (dent) the headset cups and steering will be lumpy. Retighten clamp bolt, bring stem back up. That over-center clamp that holds the stem up is adjustable, needs to be tight to not rock, just loose enough for you to easily undo it.

Handebar rocking sensation can also be loose main frame folding joint, that is also adjustable, needs to be tight, and I recommend also putting a locknut on adjustment so it stays put, otherwise you will be adjusting it monthly.

If you change the stem to the later telescoping one, there can be a compatibility issue: Your rigid stem has more of the fork steering tube sticking up to clamp around, the later telescoping ones used less tube sticking up; As a result, when I swapped out my frame (newer frame had telescoping stem) due to the problem noted below, but kept my older (more rigid) stem setup, I needed to also use the older fork.

Check the bushing between the seat tube and seat post; If (silver) aluminum, fine. If black plastic, replace immediately; The plastic compresses more than the aluminum, causing increased metal strain at the front horizontal slot at the top of the seat post, causing cracks there, and the frame becomes junk. The aluminum bushing also reinforces the steel seat tube in bending. Aluminum bushings are available aftermarket online. Make sure you get the inside and outside diameter correct. This crack got much worse over years and I had to replace the frame:



What is possible (same bike with later frame after crack above):