Had total handlebar failure on my road bike yesterday - bar sheared straight through next to the bolt holding it to the stem. Wasn’t doing anything extreme, didn’t hit a pothole, was just cruising along a flat straight road and it went with no warning - I didn’t even figure out what had happened until after I’d picked myself up out of the ditch. I’m counting myself very lucky that this didn’t happen when I was descending or in traffic as it could have been a lot worse.
I’m now wondering whether there was any way of predicting this would happen or if other people change their bars periodically? It was an OEM aluminum bar that’s been on the bike 10 years. Hasn’t been previously crashed, hasn’t had clip-ons attached to it, the stem bolts were done up with a torque wrench, but those bars probably have done something in the range of 30,000 miles including some pretty rough roads. So I’m guessing metal fatigue. I’m not normally too bad on bike maintenance - I’ll check bolts regularly, check chain and cassette wear, fix anything that is causing noise, etc. It just never really occurred to me that bars could fail like that with no warning, and I’m now wondering if I’ve been stupid. Should I be changing my bars every few years? Using steel bars instead (it’s a commuter/training bike, reliability is at a higher premium than performance)?
Personally, I replace my handlebars every 20.000km to prevent failure due to material fatigue. In former times, it was advised in the magazine, to change lightweight MTB bars every year.
I am just not sure wether stems have to be replaced too.
All aluminum bars have a fatigue life and will eventually fail. No way to accurately predict it but a close inspection of these bars last week would have shown some cracking in that stem clamp area, no doubt. So, periodic inspection and replacement upon finding defects would be the best bet.
How often do you change bar tape? Sweat is great at accelerating pitting corrosion, and depending on the stem material, you may have had galvanic corrosion. Aside from that, fatigue is cumulative and that butterfly flapping its wings may be the final load to break it, not a high load event.
All aluminum bars have a fatigue life and will eventually fail. No way to accurately predict it but a close inspection of these bars last week would have shown some cracking in that stem clamp area, no doubt. So, periodic inspection and replacement upon finding defects would be the best bet.
This PLUS changing when they get old even if you don’t see a specific problem. I’m not sure how to define “old” but certainly after five years of regular use. Maybe less.
Also, one defect is a change of more than a few millimeters in the width of the bars - measure them at the ends of the drops once or twice a year and if you spot a change, change the bars.
The only part that has broken on me was a Ritchey crankarm. It did creak for awhile before it broke, but I was in a road race and didn’t have a chance to inspect it… figured it was just a random noise.
I never replace things just because they are old. IMO age doesn’t have a lot to do with it unless they are a super light part, or they have >100k miles.
Because the bars and fork are so critical, I’m very alert to noises on the front end, and “test” my bars every few weeks by torquing them fairly hard. If they feel normal and don’t make any sounds, then I figure they are good. I have carbon bars, BTW with ~30k miles.
IMO your best bet is name brand middle-range parts that are fairly stout… then check them periodically and hope for the best.
usual recommendation for aluminum bars is 5 years… I have pushed it on some older bars to near 10, but that probably wasn’t a good idea.
http://zinncycles.com/Zinn/index.php/archives/3139
“All metals other than aluminum have a “fatigue limit,” which is the stress below which failure will never occur. With aluminum, failure can occur even at very low stresses, given enough stress applications.”
Alexander Kirichenko at 1989 worlds, handlebar snapped in half, he threw it inside the track, grabbed the stem and finished 3rd…
last year I was JRA and a rivet snapped on the rear der, it was only 15 years old…
usual recommendation for aluminum bars is 5 years… I have pushed it on some older bars to near 10, but that probably wasn’t a good idea.
http://zinncycles.com/...ex.php/archives/3139
“All metals other than aluminum have a “fatigue limit,” which is the stress below which failure will never occur. With aluminum, failure can occur even at very low stresses, given enough stress applications.”
That is just not true. I’m pretty confident only certain alloys even have this “fatigue limit.” Carbon fibers themselves are essentially immune to fatigue as I recall.
For the OP, everything breaks sooner or later. I had a 30 year old bike with as far as I knew the original handlebars. The steel head tube cracked thru on that one. Maybe buy the same kind of bars you had but replace them every 9.5 years? No promises.
“All metals other than aluminum have a “fatigue limit,” which is the stress below which failure will never occur. With aluminum, failure can occur even at very low stresses, given enough stress applications.”
That is just not true. I’m pretty confident only certain alloys even have this “fatigue limit.” Carbon fibers themselves are essentially immune to fatigue as I recall.
I’d say it’s more a problem with the assumption. Classical fatigue is much different than a fracture mechanics based theory of failure, where each application of load will grow a crack more. Add even composites are not immune to this.
Just last week I did a report about how aluminum does not have a fatigue limit. Specifically, I focused on Hincapie’s '06 steerer tube failure, not really a fatigue failure, but an interesting coincidence that we’re on ST talking about it now.
Let me tell you, the more I learn about failure in metals, the less I want to ride a bike, drive a car, fly in a plane, etc. However, if we avoided activities because of potential mechanical failures, we’d lose our f-ing minds. Anyway, as others have said, regular inspection is critical. I’d say every 3 months if you’re riding regularly. Be aware that some cracks will/could be very difficult to see, so inspect carefully.
Had total handlebar failure on my road bike yesterday - bar sheared straight through next to the bolt holding it to the stem. Wasn’t doing anything extreme, didn’t hit a pothole, was just cruising along a flat straight road and it went with no warning - I didn’t even figure out what had happened until after I’d picked myself up out of the ditch. I’m counting myself very lucky that this didn’t happen when I was descending or in traffic as it could have been a lot worse.
I’m now wondering whether there was any way of predicting this would happen or if other people change their bars periodically? It was an OEM aluminum bar that’s been on the bike 10 years. Hasn’t been previously crashed, hasn’t had clip-ons attached to it, the stem bolts were done up with a torque wrench, but those bars probably have done something in the range of 30,000 miles including some pretty rough roads. So I’m guessing metal fatigue. I’m not normally too bad on bike maintenance - I’ll check bolts regularly, check chain and cassette wear, fix anything that is causing noise, etc. It just never really occurred to me that bars could fail like that with no warning, and I’m now wondering if I’ve been stupid. Should I be changing my bars every few years? Using steel bars instead (it’s a commuter/training bike, reliability is at a higher premium than performance)?
Yeesh - glad it wasn’t worse. Thanks for the reminder, too. I have one bike with alloy bars that are about 6-7 years old (with a lot of miles on rough pavement) - time for some new ones. I also think it’s smart to replace forks with aluminum sub components every 5 years or so; we all saw what happened with Hincappie at Roubaix (broken steerer… and collar bone). It always feels weird buying new parts just to throw away the old ones that aren’t broken yet… but I’d rather do that than risk a bad crash.
“All metals other than aluminum have a “fatigue limit,” which is the stress below which failure will never occur. With aluminum, failure can occur even at very low stresses, given enough stress applications.”
That is just not true. I’m pretty confident only certain alloys even have this “fatigue limit.” Carbon fibers themselves are essentially immune to fatigue as I recall.
I’d say it’s more a problem with the assumption. Classical fatigue is much different than a fracture mechanics based theory of failure, where each application of load will grow a crack more. Add even composites are not immune to this.
you guys are arguing with Lennard Zinn about bike construction… I know who I’m going to trust…
Thanks for all the good posts and to the OP for letting us know. It’s good to be reassured that routinely swapping out things like bars is good peace of mind.
While on the topic, how often should one switch carbon fiber road forks?
usual recommendation for aluminum bars is 5 years… I have pushed it on some older bars to near 10, but that probably wasn’t a good idea.
Time is nonsensical. You might ride 1k miles per year or 30k. And you may put a lot of stress on equipment or not.
“All metals other than aluminum have a “fatigue limit,” which is the stress below which failure will never occur. With aluminum, failure can occur even at very low stresses, given enough stress applications.”
Also meaningless. Bike parts are not designed to last forever, none of them!.. even if the part is steel or titanium (which have fatigue limits)… because guess what… many stresses will be over that limit. In most cases you can make an aluminum part that is lighter and longer lasting than steel or Ti.
Replacing parts just for “peace of mind” doesn’t really work, unless you know that it has been overstressed. Material and manufacturing defects and corrosion play a big role also. A typical set of bars might last for 1k miles or 100k miles, depending.
If you want durable aluminum, I’d advise getting fairly heavy but good quality bars and stems with 6061-T6 alloy… it has good corrosion resistance. Higher strength 7075 and 2024 alloys are likely to be lighter, more expensive, and shorter lived.
“All metals other than aluminum have a “fatigue limit,” which is the stress below which failure will never occur. With aluminum, failure can occur even at very low stresses, given enough stress applications.”
That is just not true. I’m pretty confident only certain alloys even have this “fatigue limit.” Carbon fibers themselves are essentially immune to fatigue as I recall.
I’d say it’s more a problem with the assumption. Classical fatigue is much different than a fracture mechanics based theory of failure, where each application of load will grow a crack more. Add even composites are not immune to this.
you guys are arguing with Lennard Zinn about bike construction… I know who I’m going to trust…
Depends on what you mean by arguing. If you mean not trusting an antiquated failure theory of fatigue, then yes. In my line of work (aerospace) we’ve moved to the later part of the 20th century and use fracture mechanics. Sure there are knockdown factors you can apply for fatigue, but when it comes to catastrophic failure, I trust fracture mechanics. Just do a search for NASGRO.
Thanks for all the good posts and to the OP for letting us know. It’s good to be reassured that routinely swapping out things like bars is good peace of mind.
While on the topic, how often should one switch carbon fiber road forks?
carbon doesn’t have the problems aluminum has… as long as it hasn’t been crashed or knocked about, indefinitely…
washing and polishing the bike regularly and inspecting, that’s how I keep an eye on things…
so, I trust your expertise in aerospace tech. But I think Lennard knows more about bikes than you do…
what happens if you run NASGRO on a sample of bike handlebars ?
has the theory of endurance limit for aluminum been refuted by NASGRO ?
I don’t find any such papers in a quick trot through the literature…
it is well known that aluminum bars can fail suddenly and unexpectedly, has been for some decades now. This accords with material science predictions, at least all those I know of. Do you have other references ?
