danallen

Is this aluminum oxide? Whatever it is, why is there? Is it part of the reason the handlebar is broken?


Broken aluminum handlebar.

Geepig

That is amazing, and yes it does look like aluminium oxide from the slow corrosion and then flaking off of the aluminium oxide from the parent as the handlebars flex and/or cycle through temperature.

Do you know how old the bars are, how long they have been wrapped - and what kind of weather do you have?

I hope they did not break while you were out riding!

Amt0571

Have you used the bike on a trainer and sweated a lot over the bars?

I have no idea why this would happen, but a while ago I saw someone who had this happen on a bike he used on a trainer and he said the manufacturer told him it was caused by lots of sweat over the bars.

JaccoW

This is typically because of people using the bike indoors on a trainer and having very corrosive sweat. Especially if the bike is never cleaned the soaked bar tape will eat through the bars in time. That time can be as little as a year.

The other option is this being a triathlete's bike. In which case I would suggest not doing a sniff test. It might be urine.

But it's most likely sweat. I would suggest replacing your bartape more often so you can spot it sooner.

easyupbug 

Yes that is Al oxide and as said above it is the cause of the failure. No doubt more common on trainers but cyclists that have the tape get wet from sweat over time have crashed with similar failure. The last quality I look for in bar tape is long lasting.

Andrew R Stewart 

This is why many components are considered to be a race season item, not a multi year investment. I've seen about the same, but not yet resulting in a broken bar. Andy

jadocs

You need to have a towel over your bars when you ride on the trainer and make sure you don't leave your sweat all over your bike. Sweat does nasty things even riding outside. If your a big sweater and do not regularly clean/maintain your bike you might want to check for corrosion/rust around the front/derailleur and the rear caliper (if you have disc).

billnuke1 

I have seen something close to this condition on a bicycle, a very nice bicycle, stored in a pool chemical storage area...I’m going by memory...I think the pool chemical fumes pool at the floor level...the chemical affects the part of the bicycle closest to the chemical pool...depending if the bicycle is store upright or on it’s handlebars...

mack_turtle

I've seen this a lot working in shops in hot climates. sweat is very corrosive.

Amt0571

Are you talking about the handlebar? or the tape?

I don't think you need to replace the handlebar every year. But removing the tape to inspect things is a good idea. The same applies to the rest of the bike IMHO.

I remove the seatpost, fork, cranks, etc... at least once a year to inspect everything for cracks or damage that can result in failure or malfunction.

cyccommute 

Yes, that’s aluminum oxide. The reason it formed, and the reason the bars broke, is due to chloride in sweat. There are a number of ideas on how this happens but there is no general consensus on the exact mechanism. Take the rest of what I say with that in mind. Likely, the chloride ions in sweat break down the oxide layer (anodized layer) on the aluminum by displacing the oxygen atom on the aluminum oxide forming aluminum chloride. Aluminum chloride is unstable and exchanges the chloride with oxygen, likely forming a bit of hydrochloric acid in the process. The material formed is more aluminum oxide which has a slight different crystalline structure to the anodized aluminum oxide layer. The HCl then attacks more of the oxide and the process continues. As long as there is water about, the process will continue until all available aluminum is consumed. Salt provides its own water by sucking it out of the air because salt is hydroscopic.

I’ve been seeing a lot of these kinds of pictures lately and I think it’s because of the increased use of indoor trainers. Outside, air flow tends to dry the sweat and keep most of it off the tape. Indoors, the sweat from your hands soaks the bars because there isn’t airflow. There may even be higher amounts of sweat from drips and from the sweat flowing down arms. The tape holds the moisture in and exacerbates the problem.

Aluminum is great stuff but it is a reactive metal. If this is your bar, perhaps you should unwrap the bars when it is on the trainer or get a different bar (or bike) for use on the trainer. A pair of old, heavy, chrome plated steel handlebars would stand up a lot better.

cyccommute 

I’d say handlebars, especially if the bike is used extensively on a indoor trainer. Or, like I said above, get a different handlebar for a trainer.

cxwrench

And this is why you replace your bar tape every few months.

danallen

Last time I had the tape off the handlebar was a little more than a year ago. No sign of trouble then.

I live in Houston, sweat is for sure a factor here. I don't have a trainer.

The break occurred while I was riding, but did not cause a crash. It happened gradually. I thought the clamp of the brake/shifter lever had become loose, so I stopped to tighten it. I was puzzled why the clamp screw was tight but the shifter was moving around. In fact, the "looseness" of the lever increased. I thought something was wrong with the clamp. After riding another mile or so, happened to be going slowly. I pulled on the brake, putting more weight onto the handlebars and that is when it broke free completely. At first, I thought the movement of the brake lever was related to the clamp. I thought I must have loosened it when I had tried tightening it, even though that did not make sense. I knew I was turning the screw the right way. The idea of a broken handle bar did not enter my head at that point. The combination of the break occurring under my palm, so that half my hand was on the bar nearer the stem and the other half on the broken off piece caused to me recognize the break without loosing complete control where I was holding on. I rode home holding the bar somewhat together but I could not use the brake level on that side anymore. When I tried, the force would move the broken off end of the bar instead of moving the lever.

The handlebars appear to be original, the bike was made in 2009. I would emphasize, however, all the damage occurred over a period of about 15 months. When I had the tape off, installing new cables, the handlebars were pristine.

Koyote

That, and it's a nice way to freshen up your bike's appearance for only a few bucks.

danallen

Yes. Much sweat. Crazy amount of sweat. Houston heat combined with my propensity to sweat, which I have had at least since high school. On our 10-mile cross country training runs, I would come in with a drenched shirt. Nobody else was like that.

danallen

Can you think of other components subject to this sort of breakdown?

danallen

Front derailleur looks ok. I clean the bike when it gets dirty

I think a looksee at the steerer tube inside the head tube of the frame is in order.

danallen

Can you think of other components attacked by sweat? I live in Houston. I sweat a lot for sure.

I have been thinking carbon fiber components, such as the seat post and seat tube, are unaffected by sweat

jadocs

Look behind the cage and around the pivot.

djb

I did some work on a friends bike once, a bike that had been hardly used, had been stored in his shed for ages, so out of rain etc, but had some areas that were super corroded, sure enough, it was the pool chemicals stored in the shed.
wasn't anything like this, but the non stainless steel exposed bolts and stuff was pretty bad. I even sanded some stuff and painted them with black tremclad I had around for my front railing.

danallen

I think your advice is very much in order.

It's been more than a year since I had the tape off. I have had the crank pulled apart quite a bit, after finding out the hard way the bearings do not last forever. I never have taken the fork out. I am going to do that immediately. I been doing a good job with the drive train, apart from a beat bearing cartridge in the freehub. I have been holding out, determined to replace that bearing without having to buy a new free hub. The problem I have with that is I have not found the bearing I need, and I am not sure what model hub it is. I have had the seat post out a few times, due again now.

cyccommute 

I don’t think this happens only on trainers but I’ve been seeing a lot of this kind of breakage on-line lately that is trainer related. Your location is kind of a triple whammy when it comes to corrosion. You have high humidity which allows sweat to accumulate rather than evaporate. The high humidity allows the salt that you deposit on the handlebars to keep working away when you aren’t riding. And you live near the ocean where the salt concentration in the air is higher. All three work together to make a perfect aluminum corrosion mechanism.

You might want to consider a different handlebar material. Titanium would never have a problem. It’s pricey but the cockroaches that take over when we are gone will appreciate them Carbon might be something to consider as well.

By the way, I can tell you spend a lot of time on the hoods.

If you’ve been riding more because of the obvious, you might have put more salt on the bars then usual. The rate that corrosion of aluminum occurs can be rather fast given the right conditions.

danallen

That is a fact. Is that bad?

cyccommute 

It was just an observation given where the corrosion occured. But according to some it is. Not me, but some people will tell you that you are going to die...literally. I won’t link to the (closed) thread but I have been told that riding on the hoods will lead to my death because I can’t hang onto the bars if I hit a bump. I’ve hit lots of bumps on the hoods. ‘Twas a stupid argument.