storckm

My black trekking handlebars arrived in the mail from Nashbar today. I was surprised to see a number of warnings, including the suggestion to replace "dented, bent, or scratched handlebars before riding." When is replacing a handlebar really necessary?

FBinNY 

It depends on the alloy, temper and construction, and the location of the damage.

Modern handlebars are often built of loss forgiving alloys (like 6061 or 7000 series) and these can be prone to breakage at scratches or notches. The earlier stuff could be ridden post crash with no worries. OTOH the older stuff was heavier.

Also, deepen than just cosmetic scratches near the stem are of greater concern than similar scratches would be farther outboard. This is because of any lever is always more likely to fail near the fulcrum. (A physics lesson children learn at an early age if they live in cities where seesaws are made of wood.

Other than a legitimate concern about potential breakage, expect to see more stickers like this on everything as the first line of defense manufacturers erect against lawsuits.

fietsbob

the nature of Alloys of aluminum (and Ti) is the scratch can become a stress rise with fatigue

and become the Break , fault line..

When , depends on the situation super light and racing Cyclocross , I wouldn't get too attached to any handlebar

ditto for rough mountain biking ,,

Andrew R Stewart 

Having watched three different bars break and dump the riders I'm careful about them. Well, actually I don't take any unique precautions but I also don't use the stupid light stuff that's been so trendy in the last decade. Andy.

FBinNY 

I also don't like worrying about bike failures. I'm still using 2000 series alloy bars from the Bronze Age.
I like saving weight as much as anybody, but I'm finicky about where and how it's done.

AnkleWork

The greatest danger from "dented, bent, or scratched handlebars" is to the manufacturers and sellers from false or exaggerated claims of liability.

rydabent

Those warnings are kind of like "lawyer lips" on drop outs. Just use careful observation and commons sense if something damages them.

wheelreason

No doubt those warnings have as much (or more) to do with liability than anything else. However, handlebars and stems is not where I'm concerned with saving weight. I'm not a fan of pavement dentistry.

arex

If the bars crack at an inboard scratch, how much warning do you typically get? It doesn't really just up and snap in an instant, does it?

cyccommute 

When they are "dented, bent or scratched" Sometimes before they are dented, bent or scratched. Back in the mid90s "hyperlite" was all the rage in mountain biking. Combine a 25.4mm aluminum tube with a very thin wall and add in a lot of off-road impacts and you have a recipe for disaster. It was suggested at the time to replace those kinds of handlebars at least yearly. Modern handlebars...especially mountain bike bars...have a larger cross-section at the stem which increases their strength and rigidity. They can be made pretty light without the level of failure of the old hyperlite bars.

But, in all honesty, if you have managed to dent a handlebar, you should replace it. If you have managed to bend a handlebar, you should definitely replace it. If you scratch a handlebar, it depends on how deep. If you can see through to the inside of the handlebar, put away the hacksaw and replace it. If you can barely see it, keep riding. Anything in between those extremes is a judgement call.


It depends. Cracks in aluminum can propagate quickly but the material doesn't shatter like glass (as some would have you believe). Aluminum is a soft metal. It tears more than it shears. I've had lots and lots of aluminum parts and frames fail as well as having lots and lots of steel parts fail. I can not recall having had an aluminum part shear off with a loud "PING!". All of my aluminum failures...frames, wheels and cranks... have sent all kinds of signals of impending failure. All of the failures have been proceeded by creaks and groans for a long time before failure. I didn't really pay attention to the creaking and groaning so the final failure can be somewhat surprising but the signs were all there.

Steel parts, on the other hand, have never given any sign of impending failure. They all when "PING!" and failed. Axles that have broken have just sheared into two pieces. Spokes just pop. Frames have been fine one second and have been broken the next. Pedals just shear right off and put you on the ground...hopefully without ripping your legs to pieces on the way down. This makes sense when you look at the properties of steel. It's a stiff, brittle material. It's strong but once you've developed a crack, the crack will propagate rapidly across the part.

Andrew R Stewart 

While I've seen only a few bars (both drops and flat) that have had cracks near the stem (including working through the 1990s Specialized recall) these were all still in one piece. It was during the service of the bikes that these cracks were found (and there's something to take away).

The few I have watch break during riding came quite quickly. But all of these were drops that had cable routing holes drilled in them and rather crudely at that. Two with the same rider who, while "sprinting' away from a stop, simple found the rt side of the bar in his still rising hand. He basically did a dive down to the drive on the left.

So to answer the question as to the rapidness of a stress riser giving out completely- I think that the answer is an opinion. In that if the rider had no knowledge of a started crack, the failure will be called "instantaneous". And if the rider regularly looks for the signs of failure he will say there's almost always an indication of the pending failure. And that's the other take away, check your equipment periodically! Andy.

BikeWise1

A few years ago, a customer came in for a tune up and bar tape job. Upon removing the old tape, I realized the bar was covered in a foul-smelling salt/sweat/powdery crust mix. This man's sweat was particularly corrosive, and there were literally holes all the way through the aluminum in several places, mainly just below the brake levers. These were unhardened plain alloy bars. Horrified, I called him and told him of the need to replace them. He brushed this off as an attempt to pad the bill and told me to retape the bars. I did as he asked, but noted my objections on the work order. 4 months later, I received a letter from an attorney seeking responsible parties to the failure of Mr. X's bicycle after we had worked on it. The bars had failed while Mr. X was sprinting in the drops and he had crashed badly, taking a few others down in the process. I faxed over a copy of the original work order with my objections noted, and underlined the part about "CUSTOMER TOLD DO NOT RIDE HIS LITESPEED BICYCLE, SERIAL # XXX UNTIL HANDLEBARS ARE REPLACED". Below that was a line that said "I acknowledge the danger and will not ride this bicycle until properly repaired", and patted myself on the back for having had the foresight to have the customer sign underneath. I followed that with a letter asking if his client was an adult, capable of making decisions, possessing the ability to follow directions, and was able to comprehend written English.

I never heard from either of them again.

So I get why manufacturers cover their products in warnings, but with handlebars, they're generally pretty cheap, easy to replace, and not worth breaking your face over. When in doubt, replace it.

Andrew R Stewart 

This posting opens up a whole 'nuther thread. I've been in the same place as BW1 has been in and have "gotten out of the line of fire" because of the service ticket write up that i did a couple of times. I also am surprised at how complacent some shops I've worked in have been about how they note and get sign offs of questionable conditions that are not repaired. Perhaps some one will start a thread on the topic of shop service tickets and customer notifications. Andy.

3alarmer 

...I've had one alloy bar failure at the stem junction. it did not completely separate, but
I still pretty much lost control of the bike, but did not crash, so I guess you get "some" warning.

Nevertheless I found it very disconcerting, and generally try to use bars with a steel sleeve
at the point where they run through the stem. I see guys using carbon bars around here, and
I think that they are way more adventurous than me.

FBinNY 

On the flip side, I saw a carbon bar save someones life once. We were in heavy traffic on a fairly narrow arterial road. In a place where you'd least expect it, my friend was doored. He caught the edge of the door on the handlebar, which normally would have the bike turn into the car and throw him into the traffic. Instead, his carbon bar shattered and he was able to slip past the car, and managed a controlled stop.

This almost had me rethinking my tough Fiamme bars, but not quite.

BTW- one of the negative consequences of boilerplate warning stickers on everything, is that there's no way for the user to discern between boilerplate and serious warnings of an important hazard. Not all aluminum bars are equal. Those riding heaier mid level bars can probably ignore the sticker as boilerplate, but it could be a serious and meaningful warning for those riding top end ultralight bars. Unfortunately, unless the user alrady knows the difference, he has no basis on which to decide.

Coal Buster

Yet, if he'd sold the bike immediately after and someone else had crashed, not knowing of the problem hidden by the your tape job, I wonder if your signed receipt would have gotten you off the hook.

BikeWise1

Pretty sure my attorney would argue that the bike was sold in a dangerous condition of which the owner had, from his own admission, been made fully aware.

TiHabanero

Bell ain't BSing when they put those labels on their carbon bars. Customer crashed his bike, the first and only time he crashed. Kept riding it and a year later broke his collar bone when the thing let loose.

Matariki

I had a set of GB bars break on me while riding. Perhaps it was related to the older alloys, but the incident was rather gradual. The left side of the bar felt a bit odd when I pulled up on in when climbing. The next stroke it moved up a bit and the stroke after that it broke free (at the stem). I was able to slow and stop without incident. I can't recall seeing any scratches and the bars had never been subjected to any other big stress. My guess is that they were infected by the old Ava Death Stem in which they were mounted.

storckm

Well thanks. I did slip on the ice--I was completely unharmed--a week or two ago and scratch a different trekking handlebar. Nowhere near deep enough to see through, and I plan to keep on riding them. Trekking handlebars don't seem particularly super-light, but I'll keep an eye out nonetheless. At the moment they're untaped.

noglider 

I imagine myself as someone who would never break a handlebar. I'm thinking bigger, more brutish riders are at greater risk than I am. (Is that misguided?) I'm building a track bike now and plan to start racing this year. I know steel bars are more common on the track than elsewhere. Should I seriously consider using steel bars? If I'm not super strong, why is steel preferred for track racing?

FBinNY 

Handlebars don' break because of the rider's weight. They break when pulled back such as when climbing or sprinting. Steel is used on the track because sprinters pull on them very hard. Pursuiters and other non sprinters can use anything.

Kimmo

Not sure where you're drawing the line of stupid, but all the light bars of recent years are 31.8mm - and a 22% increase in diameter is nothing to sneeze at. And we'll say nothing of the stem's clamp holding on tight enough to prevent rotation...

A drop bar could probably be 80g or more lighter at 31.8mm than 26mm, without compromising any strength. Thinner walls may be more subject to forming stress cracks from scratches, but if the bar is flexing much less it's pretty academic.

I'd draw the line at 220g for an ally road bar, myself... not sure about carbon ones.

Given carbon needs the protection of clearcoat against UV and moisture, and bars cop stem clamps, brake clamps and cable rub, I'm not sure it's a very clever proposition in the long term.

Pepper Grinder

You did yourself, your shop, and your customer a disservice by agreeing to tape the bars and make the bike rideable with an out-of-sight-out-of-mind accident waiting to happen. If that was my customer, I'd lay it out - it's either new bars or the bike will be returned as-is. Or at the very least, otherwise worked-on but untaped, handlebars removed.

There's no reason a bike should go out ready to ride in dangerously poor condition, disclaimer or no.

BikeWise1

With all due respect, you weren't there.

Many, many times have I turned away work for safety concerns. This situation involved an older, established member of the local cycling community, who, because he's also one of those "never pay retail at all costs" kind of guy, promised he'd mail order some new bars. I'd rather not have to exercise diplomacy, but in this case, I did what I felt was best at the time.

In the end, he paid the price for his penny-pinching, because rather than replace one handlebar, he ended up paying to fix three bikes and one person.