Are folding handlebars a good idea from an engineering standpoint?

Question

A couple of Chinese stores have been selling folding handlebars:

At first glance this appears to be a great idea since the handlebar width is one of the reasons that carrying and storing bikes can be a problem.

From an engineering standpoint, are these types of handlebars feasible?

Answer 1

Well, from an engineering standpoint, no. It increases complexity, cost and weight. Those might be a deal breaker for the commuters who would likely use them. From a practical standpoint, maybe. @NL_Derek; you could be the first to test one!

In conjunction with other folding components (frame like a Dahon & pedals), it may suit the users need, imagine putting your bike in a suitcase.

If we assume that the design criteria are such that we need a folding handlebar, nothing here jumps out at me as anything that could not be adequately addressed with quality engineering. You could say a folding bike or folding pedals appear to be very dangerous, but if they are well engineered and manufactured with quality, there is nothing inherently dangerous about them. Whether this particular item is well made, can't say. @RoboKaren, I'd agree that something other than the threaded connection between the two halves might be better unless it has some measure preventing it from loosening unexpectedly, like a cam-lock mechanism of some sort.

Just for kicks, I modeled up what in my estimation would be a sturdy hinge assembly, if made with the right materials, roughly copying the design of what is shown in the picture. I don’t have time to do a joining detail though…

Answer 2

Running through a quick list of "engineering considerations" that I've just made up:

1. cost
   These will cost more to design, test, manufacture and assemble at point of sale than conventional handlebars. They're more complex, so I can't see any way around the extra cost. The benefit seems to be slim outside of some fairly specialised scanarios, and for many of those a conventional folding bike is probably a better choice - in a house where bikes are left in the hallway, for example, a folding bike might be able to be stored elsewhere, freeing up even more space in the hallway.
   Since most bikes are built to a price point, especially at the commodity end which the picture suggests is the target for this model, the extra cost of the folding bars has to come from other parts of the bike.
2. weight
   For equivalent materials and design, these will be heavier. On cheap bikes and BSO's this isn't an issue, but for a bike where an extra $20 for folding bars isn't an issue, weight usually is. Again, this just means the folding bars have to be useful enough to overcome the disadvantage, but it will serve to somewhat limit the market.
3. failure modes
   Obviously two pivots and a join mean there are more ways for this to fail. As well, since it's a new design we don't have 200-odd years if history to look back on. So it's going to require more testing and more experimentation to work out how it fails and how to minimise the extra failure modes.
4. aesthetics/customer perception
   This is possibly more "sales engineering", but they look odd. Most people like to fit in, and looking odd means less of that. Again, shrinking the market for the product.
5. complexity of operation
   It's a couple more steps every time you have to fold them. It likely takes as long to fold the bars as it does to fold a decent folding bike (I used to ride a Birdy and would often half-fold it just to park it). Even if they're not being folded or unfolded, that lockring in the centre should be checked every time the bike is ridden.
6. legal liability
   Again, not a factor everywhere, and not a factor at all if you're buying from a Chinese website. But the extra failure modes, extra operator checks required, and unusual design would make lawyers in a country like the US unhappy. Or excited, depending on which side of the case they're on.

It's the sort of thing that I would happily buy if it filled a need I had, but I would also be aware of the above and take care with the folding handlebars when I got them. For my folding-bed load bike they might have worked better than the "just turn the handlebars a bit" approach I used when I parked that in a hallway. But I didn't buy a set even though I'd seen pictures of them, because I wasn't convinced that they'd work well enough to make up for the above problems.

Answer 3

Other posters have pointed out that it's vulnerable to catastrophic failure, so I wouldn't use it for my 60mph racer (if I had one !-). But for an everyday getting-from-A-to-B bike, it sounds like a great idea. I have often needed to loosen the handlebars to fit a disabled (flat tyre, lost key, etc.) bike into a car (using a handy stone if I don't have a hammer), this would simplify things quite a bit.
I'd need to see and feel one to assess how sturdy it really is (@DanielRHicks apparently thinks the black bits are plastic, @RoboKaren thinks they're cast metal, in any case they need to be fairly substantial).
Do you think they're going to be available in the Netherlands? If they are any good, I predict a good market!
EDIT: @renesis pointed me to the advert which makes it clear that the black is plastic (they say: "commonly used in aviation").

Answer 4

At first glance, these handlebars appear to be very dangerous. There are multiple points of failure any of which would immediately render the bike not only steerable but likely not allow the operator to brake either:

• If the center locking nut fails to secure the two halves of the handlebar or if it works its way loose by vibration
• Each half relies on the black metal casting which is set up a lever arm and thus quite vulnerable to stress fractures.

Answer 5

We spend a lot of effort to develop this type of folding handlebars. Our works have passed EN14766 mountainbike test. I wish you may try this one.

The innovative Smaller bicycle folding handlebar can effectively avoid the unpleasant nuisance of bicycle parking in a confined space. Without much effort, steps four take less than 3 seconds to fold the handlebar up or to fold it out.

Reliably, its material of aluminum alloy ensures its toughness and resistance,. Over the past years' tests of endurance and impact, Smaller's folding handlebar has took certification of EN14766 (Mountain-bike test).

Stylishly, the design of minimalistic line-up and the anodizing surface of black color make its simplicity without losing the concept of aesthetics.

Answer 6

It depends on the design. I would say yes this is not that hard for someone with Engineering skills to accomplish. What I don't quite understand is why instead of having a pivot, don't they just make it with screw mounts so the ends of the handlebar can be pulled off? A safety latch could be placed on them to lock it to prevent accidentally loosening it while riding. There could also be 2 "stubs" for the handlebar ends to rest on in a vertical or near vertical position when storing or transporting. Also for times when needing to put the bike inside a car, 1 or both of the handlebar ends can be removed to take up less room and make it easier to load and unload into/from the car.

So my answer is yes if it is well designed, well constructed, and well tested. Very good idea but not for high stress bikes. Only for light duty I would say.