It's hardly worth the hassle and niggling uncertainty to save a miserable few grammes by using ali handlebars rather than steel.
I always specify steel bars. I like steel. I used to race Big Healeys in a rough formula until you could put your thumbnail into the cracks in the chassis.
Ali isn't in fact a natural weightsaver, because the tube rim has to be made three times as thick as steel to have the same desirable characteristics, or the diameter of the tubes have to be substantially boosted somehow to recover the lack of cability of ali compared to steel. And then, on top of the fat tubes being aesthetically displeasing, the weight saved is never as much as expected and advertised. That's why my all-steel Kranich frame, despite its extra tubes, actually weighs less than my otherwise similar aluminium Dutch and American commuter/touring frames.
When vendors claim weight savings on crucial ali parts, my first suspicion is that they shaved the component for the headline weight saving. I survived my adventurous youth because I'm a five-star paranoid. I see zero reason as a bicyclist to change a proven outlook to save a few grammes that could have a disproportionate cost.
I have the same lack of faith in titanium, for the opposite reason: I broke four ti frames on racing cars in one day, every time in a different welded joint on space frames. Also, at the other end of the size scale, we have an expensive complicated watch in a ti case with a ti band, and the clip, which is made in ti to exactly the same blueprint as the steel band on another of these watches (we used to have three of these pilot's watches in various styles and casing materials and still have two), keeps breaking a year or a few after a new one is fitted. Ti is another metal the designer must really understand well if you're to trust his design, and then it is only too easy for the stamper or the welder to screw him -- and his customers.
I don't see why I should be an unpaid beta-tester -- worse, one who lays out good money for the "privilege".
Jobst Brandt, a firstclass racing car (Porsche grand prix brakes was his work, etc) and bicycle (Avocet, treadless tyres, the first electronic bike computers, etc) engineer, didn't even like forged ali cranks unless he personally knew the operator in charge of the forge. (I've not had any crank problems, but then all the cranks I've ever used were forged on their own premises by companies with decades to a century of experience in bicycles, and since 2009 I have been using mostly steel cranks for reasons nothing to do with fears of ali breakages.) That photograph of Jobst on his bike that Dan published the other day tells you a lot: that yellow bike was ordered person-to-person, face-to-face by Jobst from Gino Cinelli himself, and built in steel by the great man's own hands. That Jobst, an obsessed cyclist and a great engineer, and with a certain minimal understanding of marketing necessities, didn't like ali as an engineering material for bicycles is more than enough reason for me to proceed cautiously with weight-"saving" on my bike. Here's Dan's image of "Jobst at speed testing Avocet road slicks", leaning over at an amazing 40 degrees (measured) from the vertical:
There are probably some known-good in-house makers of bicycle components one can exclude from my strictures -- Dan mentions Nitto* by name for a good reason, and I don't believe Uno-Kalloy* will do anything as stupid as shaving the component too thin for the metal, even if only to avoid liability suits, but I wouldn't buy generic Chinese ali handlebars -- which is what most big brands and all boutique brands are -- under any circumstances. As for ali forks...
In addition, there are components made in forged ali under the supervision of German or Swiss or Japanese engineers in China or more often in Taiwan (a Japanese for whom I designed stuff was so worn out shouting at careless Chinese manufacturers -- "My Irish designer will come bomb you" (!) -- his wife made him move production to more expensive but more competent Taiwanese firms) that I'm perfectly happy to fit. An example is a copy of the first Ahead-set stem made by the original maker in Taiwan for a German company, thoroughly tested by Utopia in Germany before they fitted it to their bikes (but it isn't for weight weenies!). Another is the n'lock that several of us have on our bikes: what is not generally known is that the n'lock designer first licensed his invention to a French company, who didn't supervise production in China, which led to breakages and liability claims, which in turn caused the designer to take the matter into his own hands and move manufacture to Taiwan where he could supervise it closely.
All of that said, I don't actually know anyone who suffered a catastrophic failure of an ali part on a bicycle, but then everyone I know has one or more good quality bicycles with good quality parts, none of these BSOs (bike shaped objects) from China, and none of their bikes have the sort of mileages one would expect to find on the bikes of members of this forum. So I'm not about to start a scare story among my pedalpals, though I will unobtrusively check whether their bars and stems and forks are ali and if so crack-free.
Thanks for directing our attention to the potential problem, Energyman.
*My Nitto moustache bars (saved when I let an earlier bike go, to use in case I ever have to ride in a crowded city where my 620mm wide normal choice would be a nuisance) and Kalloy bars are steel anyway. The last time I had an ali handlebar on a bike was 2002, and it was the first thing I took off and instantly replaced with steel on the day the bike was delivered to me.
