Just caught a customer's carbon frame before it was too late

A guy brought in his gravel bike for a 'creaking sound' last Tuesday. It was a 3 year old carbon frame, looked clean. I did the usual checks, torqued everything, noise was still there. On a hunch, I pulled the seatpost and stuck a borescope down the seat tube. The inside looked like a spiderweb of tiny cracks starting about 2 inches below the collar, totally invisible from the outside. The cause? A slightly over-tightened seatpost clamp from a year ago, combined with grit that got past the grease and acted like sandpaper. The difference between a simple service and a catastrophic failure was literally one internal inspection. Has anyone else found hidden damage like this during a routine noise diagnosis?

2 comments

2 Comments

hugobarnes5d ago

Hard to believe a bit of grit and a tight clamp could do that much damage to carbon. Those frames are usually tougher than that.

umac715d ago

Yeah but that "bit of grit" acts like sandpaper when you crank the clamp down. It creates tiny stress points you can't even see. Carbon is strong but it's brittle, it doesn't handle point loads like that.