Alloy Handlebar Corrosion

[Max]

Periodically replacing tape to clean evaporated sweat and inspect for damage to alloy handlebar presumably resulting from "galvanic corrosion". Replaced two-year old handlebar recently as it had corroded completely through at the brake/shifter clamps.

Just curious if anyone may have found a more effective solution(s) for dealing with this maintenance/safety issue, i.e. insulating between the dissimilar metals, carbon handlebar, etc.

Thanks,

[oliver1850]

I've never seen that amount of damage. The newer shot peaned and anodized surface treatments seem to hold up pretty well.

I don't like perforated tape because it lets the sweat through. I think washing the tape off regularly helps too. Galvanic corrosion will always be an issue with alumimum bars and steel clamps, but I would think salt makes it multiple times worse.

[ultraman6970]

Never seen damage like that ever, dont say it cant happen tho. Maybe you sweat pure acid?

[Louis]

This must vary from person to person. The AL bars on my daily driver are over 10 yrs old and still going strong. And believe me, it gets sweaty in St Louis during the summer, and the smell of my gloves is proof of that.

[AngryScientist]

what type of bars are we talking about here? my alu bars have a great finish on them, almost powder coat looking (though i doubt its powder coat), i've never seen serious corrosion on my bars, though they see plenty of sweat and foul weather. do yours look like this?

http://www.treefortbikes.com/images/raw/TF-HB0817-4.jpg

[oliver1850]

What AS posted is what I mean by a modern finish, peaned and anodized. I've seen some pretty decent pits in old Cinelli bars, but never any perforation.

[regularguy412]

I recently replaced the Cinelli Solida bar on my CSI. There was a TON of salt under the tape. It's hot and very humid here, and I sweat profusely. The salt had eaten completely through the bar in several small places -- mostly on the lower, right side (not at the brake clamp).

Luckily, I had another bar ready to go. I decided to put a coat of clear lacquer on the 'working' part of the bar prior to wrapping. Will see how this works.

One of my riding buddies sweats a lot, too. He wraps his aluminum bars completely from top to bottom with black electrical tape BEFORE beginning the cable installation/ tape wrapping process. He's broken a bar off in his hand before, so he's a bit gun-shy.


Mike in AR:beer:

[Max]

Installed an FSA Wing Pro Compact bar in June - shot-peened, anodized aluminum. The before pic shows salt accumulation, the after pic shows approx. 1 mm corrosion at clamp.

I am a heavy sweater, and located in a humid environment on the coast of North Carolina. May check with a marine supply for options.

Thanks,

[rice rocket]

Max, did you forget the pic? I'm interested in seeing it.

[Charles M]

That aint salt... The white stuff seems like it but that's your bar.

Changes a bit with climate, but it is what it is. I've seen it here in Arizona several times on different brands.

Whish I were a good enough geek to remember the right combination that does the best (worst) job of that.

[Max]

Max, did you forget the pic? I'm interested in seeing it.

sorry, files were too large

[rustychisel]

I've seen that, and worse, mainly from people who do extended indoor ergo sessions with what I would consider inadequate ventilation.

It gets very very hot around here but its a dry heat, not so humid.

Anyhoo, yes it is salt: salts of hydrated aluminium, and I don't really know a prevention or cure save the obvious... keep dry, don't store wet, check often, don't sweat. Not very helpful, I know.

[stephenmarklay]

Learn something new everyday! I have never seen ALU corrode like that.

[keevon]

...on the coast of North Carolina.
That's the source of your problem. The sweat only contributes to the issue.

As you're aware, the steel band clamp isn't playing nice with the aluminum bar. Doesn't matter that the bar is anodized... it's still 'bare' aluminum as far as the steel in concerned. Add an electrolyte to the equation (humidity and salt), and you've got galvanic corrosion.

Ideally, you would be able to replace the steel clamp band with an aluminum band, but I don't think those are available for STI's.

Insulating the bar is the other option. I would try separating the bar from the clamp with cut-up pieces of inner tube. The rubber should prevent the electrical connection that causes galvanic corrosion to take place. Just make sure you can tighten the shifters enough that they don't slip.

[rice rocket]

Isn't aluminum oxide non-conductive? It should only conduct if you break the anodization layer.

Or go carbon?

How about sacrificial anodes? Magnesium bar plugs? Is there a market? ;)

[nm87710]

Have seen first hand corrosion, pin holes, etc. on several pairs of TTT and Cinelli AL bars over the years.

[keevon]

I'm certainly no metallurgist, but the topic is very interesting.

Check this out:
http://aluminumsurface.blogspot.com/2009/04/corrosion-between-anodized-aluminum-and.html

I don't know if the anodized layer is actually "broken", or if galvanic corrosion just takes place with anodized parts under the right conditions.

Regardless, aluminum is migrating to the steel in the clamp area. There are three options for preventing this:

1) Eliminate the dissimilar metal.
2) Insulate between the dissimilar metals.
3) Completely seal the shifter clamp area so no water/salt can intrude.

Insulating seems like the most feasible option.

[45K10]

I had a set of bars break in two at the shifter clamp during a crit. The only thing that kept the bar from flying off was the bar tape. I live in Florida you see a lot of bars corrode like the ones pictured earlier. After my experience I made a point to take the bar tape off every couple of weeks and wash the bars and the tape. I switched to carbon bars a couple of years ago which solved my "Alien" sweat problem.

[Joe]

http://bespokecycles.blogspot.com/2011/06/dont-let-this-happen-to-you.html

[bart998]

I have never seen anything like that. 10 years shop experience and decades riding on the same bars... I don't use indoor trainers though, living in Cali and all...

[regularguy412]

http://bespokecycles.blogspot.com/2011/06/dont-let-this-happen-to-you.html


Not looking for one-up-man-ship, but the bars I just replaced were much worse than this example. I'll get a pic and post. I could hardly believe it myself, when I saw the shape they were in.

MIke in AR :beer:

[beeatnik]

http://bespokecycles.blogspot.com/2011/06/dont-let-this-happen-to-you.html

I was about to post that since I was reading the bespoke blog for the first time earlier today. I was wondering if that was a common problem and trying not to give in to irrational fear as I sweat buckets even in temperate weather.

[stephenmarklay]

I am putting together my current project this week and I will wrap some tape before I put the brake levers on.

I'm certainly no metallurgist, but the topic is very interesting.

Check this out:
http://aluminumsurface.blogspot.com/2009/04/corrosion-between-anodized-aluminum-and.html

I don't know if the anodized layer is actually "broken", or if galvanic corrosion just takes place with anodized parts under the right conditions.

Regardless, aluminum is migrating to the steel in the clamp area. There are three options for preventing this:

1) Eliminate the dissimilar metal.
2) Insulate between the dissimilar metals.
3) Completely seal the shifter clamp area so no water/salt can intrude.

Insulating seems like the most feasible option.

[AngryScientist]

one solution for this might be "plasti-dip". it comes in a dippable, brushable container, and also in a spray, available at any lowes or home depot.

it's essentially a thin, very though rubbarized coating, this might be good between the bars and the elements for those experiencing corrosion woes.

http://fichtenfoo.net/blog/wp-content/uploads/2009/12/plastidip-01.jpg