MotoIdaho

Is there a way to repair a dent in the top tube of a butted steel road bike frame? Its about 3/4 inch long, maybe 1/8 or 1/4 inch deep, so pretty serious in my book. The bike is being ridden on short rides around town, with no apparent problems.

MrPhil

Can you post a pic? It's not just the size, it's also shape and location. You may be just fine. The top tube, in general, takes the least force of the main frame tubes.

Shimagnolo

Either:
a) Replace frame.
b) Put this on it to hide it: https://store.somafab.com/pawatoptupa.html

Squeazel

The best way to fix it is to replace the tube. But unless you're really fond of the frame, or it's especially valuable, this doesn't make economic sense.

It's unlikely that the tube strength is compromised to any large degree (any imperfection decreases the strength of a tube some, but bikes are usually overbuilt). It just looks bad. Fill it in with bondo, touch up the paint and ride it. Watch for cracks developing, and if a crack starts, then you need to do something more, or trash the frame.

DogsBody

A good weld-over with a re-facing grind would work no? Then re-touch with primer+paint...
As long as the frame has not been bent by the impact that caused the dent you would be okay with bondo, or (if able) a weld-over...

Old School

Or, you can just learn to live with disappointment!

rmfnla

Fill it in with Bond-o automotive body putty or solder (my preference).

Both methods will require at least some repainting.

ogbigbird

a picture is worth a thousand words. if the tube itself wasn't whacked so hard that it caused misalignment or a breach in frame structural integrity, id either bondo and touch up, put a sticker over it or learn to live with it. a picture would help me give a better answer.

Mike Mills

Can the dent be romoved without damaging the paint? I know they do this for small dents on automobiles.

DannoXYZ 

No way with tubing, it's way too strong. On autos, they are usually working on a flat-panel, which is much easier to bend back. They also have access to the back side to push out the dent.

Grand Bois

You can't expect to get decent advice on the safety of the frame without posting pictures of the damage, but the top tube is under compression and riding the bike is like stepping on an upright dented beer can.

pacificaslim

yeah, i'm sure it's exactly like that.

wrk101

Do a search on dent repair. There is no easy/cheap fix. Live with it, or have it repaired and repaint the bike.

DannoXYZ 

Crumpling a tube only occurs if you've exceeded the 50:1 diameter-to-wall-thickness ratio. No bike tubing is made that thin and the only thing that'll happen is you'll bend it. But you'll also have to bend the downtube at the same time. The only bent downtubes I've ever seen were from front-end impacts like riding into a parked car. In which case, the stress on the top-tube is in tension; a small dent won't make any difference in that case.

IntoThickAir

I've got a serious dent in my top tube, but I've done nothing more than let it stimulate questions. It's a good conversation piece, because then I must explain how I was leaving for Djibouti, Africa, but I couldn't get the bike in the shipping box because the seatpost was stuck, so I dashed down to the local garage where an old fellow with a big wooden mallet....

TallRider

I believe you with my whole heart

HillRider

Theoretically there are ways to "iron out" dents in tubing. A mandrel with tapered ends is slid into the tube and force through it either mechanically or hydraulically, raising the dent in the process. This is done often with dented shotgun barrels which are much thicker walled than any bike tubing.

However (and this is a BIG however), you have to be able to access both ends of the tubing. It might be possible to raise a dent in a seat tube but any others are probably inaccessable.

DogsBody

Okay. I think we have a concensus to what steps should be followed:
Step #1 - Post pics................................................................................................ .........................................................................................

crocodilefundy

most likely you'll be fine... the top tube isn't going to see much in the way of fatigue failure. The only time i have ever seen top tubes fail is in BMX and those were from some really bad crashes that cracked the frame. then the frame was still used until the crack propagated all the way through.

Torchy McFlux

I've had good luck popping dents out of steel tubing with a set of old wooden tube clamps and a bench vise. The paint should be removed first though, so factor a re-paint into the cost.

unterhausen

you can remove dents in seat tubes without any problems whatsoever. Top tube isn't so easy.

MotoIdaho

Hold the phone, I got pictures of my dent, but they are at home. I'll post them tomorrow.

DMF 

I dunno.. This Columbus Nivacrom stuff is very thin indeed. I like to tap on it to impress chicks. Sounds no thicker than a can of beans.* And they use asymmetrical megatube cross-sections so I bet they're pretty close to 50:1.


* Without the beans.

rmfnla

You tap on your frame tubes to impress girls?

No wonder cyclists have such a weenie inage!

DMF 

Actually, my spandex images my weenie pretty well. But at rest it's not all that impressive (especially after Tom Boonen) so I employ alternative methods.

Still, there does seem to be huge population of lesbians around here....