I was cleaning my road bike (cannondale supersix evo) and noticed a marking on my chainstay and I'm not sure what it is. Scratching it is a little rough compared to the carbon around it. This was not there before
I did take my bike into the shop a few months ago, since the wheel was sitting really close to the non-drive side chainstay, and they said it was a non issue. This was when it only had a small scratch. Now it's turned into something like this.
Should I be concerned? I have a big ride coming up and don't wanna miss it!!
Here are some pics: