Carbon frames have become the go to material of the industry and have built up quite the mystique. As we repair more and more frames and collect more and more data we aim to inform more people about carbon fiber in the bike industry. One of the most popular questions we answer is, “can you tell me if my frame is broken?”
On many bike frames they can have a couple hundred grams of clear coat and paint on them. This makes it quite tricky to tell if there is actual damage by visual inspection alone.
For those at home there are a couple quick and easy ways to inspect your frame to check for damage under all of that paint.
The first inspection technique is to rub a rag over the damaged area. In most cases the paint and clearcoat won’t catch the rag, but if there is carbon damage it will catch a few fibers as you pass over it.
The trouble with this form of inspection is that the aesthetic layer or top layers of carbon might not be damaged but due to different stresses and/or impacts there might be unseen damage to the structural layers.
The other quick and simple test that you can do at home is the “quarter tap test.” If you go down your damaged tube tapping it with a quarter it should make a consistent pitch throughout the entire tube. When you go over the damaged area if there is damage it literally will sound “dead”, the tone will be lower than the rest of the surrounding area.
These are the two easiest quick inspection techniques but if you are still in question if there is damage or not, always bring it to a professional for a complete inspection.