- Cheap Chinese carbon bars and titanium skewers. Any good?
Now he’s gone though, I do agree with his basic point. I wouldn’t use the bars in the OP’s question. I’d use carbon bars from a manufacturer (Chinese direct or otherwise) with a good rep that I could at least do some research on though.
(Hi moshi, we know you’re looking 🙂 )Posted 4 years agomoshimonster wrote:
I’ve got a 1st class and masters degree in mech eng. plus 20 years experience working directly with structures, including carbon. So I’d say I know at least as much as you do about them. I certainly don’t need a patronising ladybird book lecture from you about how two sheets of carbon separated by a bonded lightweight honeycomb core make the the resultant structure so much stronger. I’m sure you know that such a structure requires a decent section to work efficiently, typically a quarter inch core. These carbon bars are not such a construction and the primary load is a pure bending load.
You describe my comments as patronising? 😯
Carbon bars are not sandwich construction, that was just an illustration – a bar works in just the same way as a sandwich construction, with one side in tension the other in compression (clearly that is a simplification, with the force actually varying from tension to compression around the tube). No core needed, as the tubular shape constrains the outer surfaces in just the same way that the web on an I beam allows that to resist bending forces through tensile and compression stress in the top and bottom parts of the beam. You do understand how an I beam works? Well a tubular “beam” like a handlebar resists bending loads in much the same way. You’ve got a 1 1/4″ section rather than the 1/4″ core of your sandwich!
It’s easy to show that it’s the structure resisting the bending load, rather than the composite itself by cutting up a bar and seeing how low the bending stiffness is for the material when it is no longer in a tubular shape. If you have no old carbon bars to cut up, then the experiment works just as well for alu (which is no better at resisting bending forces anyway).moshimonster wrote:
It’s also arrogant and unpleasant to mock posters for actually having some relevant experience. I only bring it up when I’m being patronised by someone who clearly doesn’t know what they are talking about.
Presumably you don’t think I know what I’m talking about? It has already been done, but here’s a handy link for you
my qualifications are irrelevant to this discussion – I’m basing my arguments on facts, not qualifications.
Though presumably you won’t be reading any of this anyway, will you…Posted 4 years ago
Though back to the OP, I think I’m with moshi in being uncomfortable using a £14 unbranded carbon bar which you have no idea at all about the provenance. Because he is correct in his argument about the risk – you have no knowledge at all about those, so it is all risk, whereas with a branded component (whether western or Chinese branded) there is a certain degree of traceability which reduces the risk by providing you with some knowledge about the reliability.Posted 4 years agoNick Evans wrote:
That they’re carbon is also irrelevant, I’d be replacing aluminium bars of the same age/use quite honestly.
Well if we’re going there, personally I’d be replacing similar alu bars a lot sooner. If the composite bars haven’t received a knock I’m not seeing a major reason to ever replace them simply due to amount of use. Plenty of alu bars out there which have been in use for far longer than your carbon ones, as I don’t think most roadies would ever consider changing their bars apart from after a crash or if they want a different shape – I’ve certainly never thought about replacing mine, despite them being lighter than most carbon bars (though the current ones are only about 4yo, and 10+yo ones on my previous bike only get used on the trainer at the moment).Posted 4 years ago
One of the reasons I’ve not replaced them sooner is that I really like the shape (anatomic drops), and they don’t do them any more! VR/round just aren’t as comfy IMO.
As I said, I’m not paranoid about them, hence not having replaced them to date, nor do I expect them to fail (indeed I’ll sell them with a clear conscience). It’s just a peace of mind thing. I’m happy that I’m not dicing with death every time I sling a leg over the bike!Posted 4 years ago
Intriguing. So you’ll have peace of mind that they won’t fail on somebody else’s bike, but not on yours?
It’s a risk perception thing isn’t it? Again! I don’t genuinely think they’re about to break. I just think ‘y’know, these have been on here for a long time, they’re fairly light, I’ve clattered countless potholes, they’ve been subjected to the rigours of airport baggage handlers, perhaps I ought to change them’. If I put them on eBay and someone else decides they’re happy to take a punt on a pair of second hand carbon bars that isn’t my problem. I’m not going to lie about their age, or deceive.Posted 4 years agoNorthwindSubscriber
nemesis – Member
(FWIW, I’ve seen far more broken/bent Al/Ti bars than carbon)
Me too- I’ve even folded a steel one 😆 Never broken a carbon one despite hammering some (as in, bike falling off chairlift, outliving 2 frames) but bent 2 alu ones. Which I suppose is 100% of all the alu ones I’ve used for any length of time on anything bar a road bike.Posted 4 years ago
small update for anyone that is still interested….
Off the back of this discussion and my previous non-death experience with Chinese carbon bars I decided to take it one step further and put my life on the line* in the name of Science!
I have acquired a pair of China’s finest fake Bontrager RXL bars**, they are currently on the front of my bike and have had one outing already.
On first inspection they appear very very similar to the real ones, slight variation in the cosmetic layer, but then there will be between individual bars anyway. Wall thickness appears the same, weight is 22g heavier than the real ones, and the decals state 15mm rise, when in fact they are flat – whoops. If it were not for the decal error I do not think anyone would be able to tell the difference visually unless they were very familiar with them.
I’m basically going to use them for my normal riding until either
A> They break
B> They make sufficiently bad noises that I get scared and remove them
C> I forget they are fake.
This is simply an experiment on my part, I do not condone buying counterfeit goods, so please leave all moral arguments aside, and no need to call me an idiot, I’ve been an idiot for a while now, I have a robust coping mechanism for it.
* maybePosted 4 years ago
** chosen because I also have 2 real pairs to compare with, well I hope they are real…unovoloMember
and the decals state 15mm rise, when in fact they are flat – whoops
There is the possibility that these are genuine and the reason for cheapyness is because they are mislabeled hence QC reject.
Regards weight quite often items will deviate from the manufacturers quoted weights, check weighweenies listings for comparisons.
I have been running a cheap carbon flat bar for a while now with no issues still waiting for it to explode in a flaming ball of fire and take me with it.Posted 4 years ago
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