Originally Posted by
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!
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.