Your bicycle fell to the floor. Or you hit it hard against the car mount.
The good news is that nothing’s broken. The bad news is there’s a dent in the frame. Is your bicycle still safe to ride, or does the frame need to be repaired or replaced?
This is a valid (and important) question to ask. Many cyclists ride bikes with damaged frames without considering the risks. When I was in college and I was young and immortal, I did the same.
In general, it’s not safe to ride a bicycle with a dented frame. Although it depends on the location and severity of the dent, a dent is a dent. It weakens the metal frame and can cause it to fail when you least expect it.
Dents and dings are the most common on aluminum bicycle frames because aluminum is a soft metal. But if you try hard enough, you can also dent a steel or titanium frame.
They usually happen on the top tube, down tube, seat tube, and seat stay—the tubes not “protected” by the handlebars or pedals sticking out, which, by Murphy’s law, always seem to find their way to the edge of a wall or some other object.
Should You Ride a Bike With a Dented Frame?
If you want to err on the side of caution, don’t ride a bike with a dented frame.
Sure, the dent may look harmless to you, but you’ve no way of knowing just how much it has weakened the tube.
Your frame, after all, only has so many tubes. And each of them is there to hold the bike together and support your weight despite the Earth’s gravitational pull and the mechanical stresses from you riding the bike.
If your frame fails on you during a ride, it will usually happen at high speed, when cornering, or in a turn. There’s never a good moment for your frame to give, and yet it will always happen in the worst moment imaginable. (Needless to say, you can injure yourself really bad from the fall or crash that follows.)
Can You Ride on a Bike With a Broken Frame Regardless?
But some would argue that it’s okay to ride a bike with a dented frame as long as the dent appears cosmetic.
“Appears” is the keyword here.
First, you can never be sure that the frame is safe.
Second, it largely depends on the metal, the tube, and the dent.
A dent on an aluminum tube—when it comes to frames, the deadest, most brittle material of them all—is not necessarily the same thing as a dent on a steel or a titanium tube.
A dent on the top tube, which experiences compression and is prone to buckling, isn’t the same thing as a dent on the downtube, which experiences tension and will therefore be less affected by dents and dings.
Last but not least, a dent on a well-designed and properly constructed frame isn’t the same as a dent on a poorly designed and improperly constructed frame (where the whole isn’t necessarily greater than the sum of its parts).
This is a decision (and risk) you will have to take on your own.
If you want to know what others have done in similar situations and what they decided, you will probably find this Reddit thread and this and this forum threads interesting.
Is It Possible to Fix a Dent Frame?
Consult with a frame builder whose opinion you can trust.
Contrary to what some of you may think, this isn’t as easy as cutting off a tube and replacing it with another.
There are straight tubes, butted tubes, double-butted, triple-butted tubes… The tubes can also be tapered, which can be hard to source and even harder to replace, even by an experienced professional.
If the frame is old, fatigued, and already on its last legs, is it even worth salvaging? Inevitably, you will have to discard and replace it.
Unless the frame is valuable to you—for example, it costs a lot of money, has significant emotional value, or belongs to a vintage bicycle that you’d like to keep as original as you can—the cost and the risk of this repair procedure probably won’t be worth it.
Nine times out of ten, the cheaper, easier, and safer thing to do is to build a new frame from scratch and swap it out with the new one (or, on less valuable bicycles, replace the whole bike).
You can ride a bike with a dent on the frame. The question to ask in this situation is whether you should. (And, if you choose to, how far you will go.)
Whether we’re talking about a cosmetic ding or a serious dent, the frame won’t have the structural integrity it used to, and it will weaken. If you’re the person who errs on the side of caution, consider swapping out the frame or the bike altogether.