For the longest time, I've been having a feeling that the handlebar of my Hemingway is a little lower on the right than it is on the left, so I measured bar end to axle (when I say axle, I mean the threaded end of the QR skewer; I even flipped the skewer around between measurements to get as consistent of a reading as possible) and found that the right bar end was about 15mm closer to the axle.

Needless to say, that was a rabbit hole I just had to go down. I figured the best way to determine if I am indeed seeing what I'm seeing is to compare headtube to seat tube, and this is what I saw:







Now, for comparison, I did the same with my Launch and this is what it looked like:







As you can see, the Launch's frame halves seem to be much better aligned than the Hemingway's. I checked the Hemingway's hinge to see if there's any play there that might be causing the misalignment; I opened the hinge, held the two halves perpendicular to each other and tried to find any movement at all and found none.

Now, mind you, this is not the sort of thing you'd notice while you're riding the bike, but it's the kind of thing that, like an annoying third-grader who never shuts up, sits there in the back of your mind and keeps nagging.

So, do you guys think it's about time I put the Hemingway - my favorite bike, I should point out - up for sale?

Sorry to hear that. Looks

Visually is it obvious? Can't really see clearly from the photos?

What did the vendor/ manufacturer say about this issue?

In photo #2 the spirit level is sitting flat onto the head tube. In the next photo it's sitting flat onto the seat tube. In both cases, the spirit level is seen from the front of the bike, looking towards the back. The same applies to the next set of photos.

I've had this bike (the Hemingway) since October 2020, so I doubt that the manufacturer or the vendor would be interested in anything I'd have to say about it...

Ah I see. Did this issue appear half way thru or right from the 1st day?

It could be many things. Yours may be different from my issue. With yours, leveling on the ends of the tubes, especially small diameter but short span, may not be accurate. What matters in your case would be a level across the side of the head tube, versus a level across the side of the seat tube, however in both cases there can be local distortion due to welding. Fortunately, neither is tapered, so you should easily get readings.

I have the same issue symptom, canted handlebar, but perhaps different cause:

I have a Dahon Speed P8. The 2-piece handlepost was recalled. I bought it in to the local Dahon dealer, they replaced it in 5 minutes (they did not replace the entire handlepost, just the lower, so just raised the upper and handlebar and swapped the lower). I loaded it in the car folded and took home. Next day I unfolded it and could tell the handlebar was canted. I eyeballed from behind and could easily see the handlepost was not aligned laterally straight with the seatpost. Was not like that before. Bike was virtually unused. Bike shop would not replace again, and had already recycled old part. I looked carefully at handlepost base; It did not sit evenly on the headset, the bottom was flat but slightly canted so a gap on one side. Even if I were to machine the bottom half of the hinge to sit flat, the angle would still be off; The bore that clamps around the steer tube is off. My guess is the bottom part of the hinge is forged with the bore roughed, then final bored on a fixture, and the machinist was careless and a metal chip was between the workpiece bottom and the fixture on one side, so bore is not 90 degrees with the base. Dahon corporate also blew me off.

I publicized the matter on here, and one of the members at the time, who I thought was only a dealer, but now know they were associated with Dahon, sent me a replacement lower handlepost. I put it on. It was off-angle in a different direction, again, sloped gap between base and headset.

Here is my knowledge from the auto industry: Parts that fail production tolerance are set aside and sold as service parts. Even when you buy "OEM" parts, you are often getting "aftermarket" quality. To see two service parts both exhibiting the same quality issue, and even varying in different direction, is clear proof.

Bike still sits in storage, I bought it for someone to use and they never did. Eventually I'll replace the handlepost with an aftermarket one that is higher quality than the OEM one, Dahon's one. Oh and as I recall, the color was off too, instead of pure black anodizing, it was like dark bronze or copper in sunlight, I've occasionally seen that on other Dahon parts with age. Finish defect, clearly not intentional.

I did place the level on the sides of the head and seat tubes, eliminating the possibility of touching any welds with a ruler as a spacer, and the readings confirmed the ones that I got with the level on the ends.

I spent two whole days figuring this out, checking, double checking, triple and quadruple checking everything making sure that it wasn't all just a big mind-eff, even going so far as to swap in a fork and a handlepost from another bike that's years newer, and got the same result. I put the bike in question's handlepost and fork on the other, newer, bike and nothing changed on that bike.

Besides, I think the deviation is too great to be caused by a poorly made handlepost. I mean, just look at it:











It's obviously not something that most people would notice or even look for, but it is clearly visible. To answer an earlier question, I started having doubts some years ago after one of our cats tried to take the bike for a ride while it was leaned against a chair and knocked it over on its left side. At the time, I had a very short, one-piece handlepost on the bike, along with a high rise Joseph Kuosac handlebar:




The bike hit the ground at the bar end, with the handlebar taking the brunt of the impact. Not long after, I noticed that the left side of the handlebar was higher than the right, with the damage being at the circled bend (I found this out by physically comparing it to another, identical handlebar that I know to be good.) Now, I have no way of knowing whether this handlebar actually did get damaged because of that fall or if it was already defective when delivered, but I have no reason to think that the latter was the case.

So here we are. Whether the frame got twisted because of that fall or it was defective when it left the factory is anyone's guess.

How does it ride? Any odd behaviors?

Does this actually matter at all in the use of this folding bike?

Well it rides just fine - when I'm not thinking about it. But whenever it hits me and I look down at the handlebar clamp, I tend to pull over and take a break. Which is more often than I'd like.

(above, post #6) I agree that the misalignment is clear, just like on my bike.

The key, if it's related to the handlepost base, is whether the base sits flat on the top of the headset, all the way around, or any gaps favoring the direction of post tilt? If no gaps, than either the post above is out of alignment, or at the hinge interface, or the handlebar clamp, and if none of the above, it's the bike frame. Let us assume the latter: I don't think you could permanently twist the main beam without a LOT of force, unless the twist is all at the main beam hinge; look for signs of mismatch in the two hinge halves as it closes. If not, then I think it's an error in welding, the parts not all fixtured perfectly as the frame is welded. There is also the possibility of warping during welding as the part cools, this is a problem with many parts, but that is usually worked out in pre-production samples by changing the welding order, direction, tacking everything and then finish welds, etc. So I doubt that weld-warping is an issue, with huge experience Dahon has with those design welds for over 20 years on similar frames. So my guess is fixturing error in welding. Good statistical process control gauges, with every part measured in a fixture or go/no-go gaged, would have detected this defect instantly. But volume manufacturers usually gage first and last parts on a shift, and all the others not.

Whatever you prove as the cause of the tilt, that's a manufacturing defect, not wear and tear. And I think you are well within warranty. The issue is proving it conclusively; you don't by chance have access to a CMM (coordinate measuring machine)? On a CMM with the frame latched closed, I would contact the inside of the head tube bore to establish its axis, and do the same for the seat tube bore. And, Dahon not blowing you off, just because they can.

When contacting Dahon, besides the serial number, you'll want to send a photo of the frame hinge, as the hinge on your Launch (Visegrip I think), is different from my Launch (Jaws). Dahon is now in California USA, in case paperwork with your bike says Illinois. But you may need to go through whatever Dahon subsidiary sold you your bike. Or your dealer if you bought through a dealer.

As I mentioned earlier, I checked everything - including fitment of the handlepost to the steerer tube and the headset, as well as the hinge. The steerer tube sits nice and flush all the way around; the way it's fastened to the steerer tube and the headset is that a big bolt threads into the top of the steerer tube, sandwiching everything - the fork, the headset, and the handlepost - together via a big brass crush washer, keeping them all in line. If there was anything out of alignment, I would've found out about it; steering the bike wouldn't be possible if any component of the handlebar-to-fork assembly was our of whack, as the headset bearings would be jammed in place.

As for the hinge, I found no issues there - no play, no wear, no cracked welds. Nothing out of the ordinary.

As I said earlier, I doubt that contacting Dahon will get me anywhere. Even if it did, and even if they by some miracle decide to honor some kind of warranty, they'll still ask me to pay for shipping a new frame to Saudi Arabia - the cost of which would be so prohibitive at this point that I might as well buy a new bike - which I already did a few months ago, and ran into a whole new set of issues. See my posts about my new Launch D8 and the en****tification of Dahon.

(above) Bottom of handlepost not sitting perfectly flush on the headset is a symptom, but not a problem, it will pivot fine and smooth. What you need is my defective handlepost that cants in the opposite direction, as I recall. But like you said, shipping costs more than parts.

The top of the handlepost where it clamps to the handlebar, opens like a clamshell. You might try rolling some slender strips of heavy aluminum foil, such that the final product is ~4mm wide, and use those to shim the handlebar in the clamshell clamp at the sides, to tilt the handlebar in the opposite direction. OEM handlebars from Dahon are as thick wall as I have seen, so I think would not dent from point clamping loads. Thats all I can think of.

If the frame is tweaked and causing the handlebar to be not level, is the front wheel also not in alignment with respect to the rear wheel?

I checked wheel camber multiple times using not one, but two German-made bubble levels, and the results were consistent with what I found comparing head tube to seat tube angles: the front wheel is slightly cambered to the left compared to the rear wheel.

German bubble level? With German air in the bubble, I presume.

Everyone knows that German air is more precise.

Conversation with German vehicle dynamics engineer:
Me: Are those struts pressurized with nitrogen?
Them: They are pressurized with a complex mixture of 78% nitrogen, 21% oxygen, 1% argon, and just a pinch of carbon dioxide for flavor.

That is exactly correct. And the vertical balance point will split the difference between the camber of both wheels. I pondered a day ago, the merit of correcting for the defect via alignment of the fork blades, but while that would correct for the front wheel camber error, it will not correct for the handlebar cant, which is more noticeable than the camber error.