Crack Analysis
 

I'd love for someone knowledgeable here to have a gander at what this crack in the paint—a fault leaking rust, apparently—in the downtube of a ~10 year-old steel track frame might mean for its longevity... (For full disclosure: I have become kinda touchy as another lugged steel track frame of mine snapped at the seat tube/bb shell lug two weeks ago when accelerating from a trackstand at an incline with no prior indication of possible failure that I had been aware of.)

https://cimg8.ibsrv.net/gimg/bikefor...1d8c2dc045.jpg
https://cimg9.ibsrv.net/gimg/bikefor...f972fe2ffd.jpg

Edit: If one thinks that this is the wrong place for this sort of inquiry, kindly direct me to the proper place in the forums for this sort of query :)

The first thing I would do is try to determine if this is a crack in the tube or just the finish. One way could be to drip some fluid (WD-40?) inside the tube and then position the frame so the "crack" is at the lowest point. Any fluid seeping through to the outside?

If it is a tube crack then that tube is seriously compromised. While a tube can be replaced on a steel frame once done (including the paint/decals/shipping) the cost can be too great for most to be good with it. When the frame is a valued family item or has some pedigreed by a former owner (team, racer of note) the cost to repair starts to make sense.

Have you tried to look inside the other tubes for rust? BB shell, chain stays, seat tubes all are areas of standing water making rust there more likely. Andy

This is a brilliant idea and I'll set up the conditions for the experiment here following the postage of this message, purely for science... Since tacking my query, I reviewed earlier photos of my time with this bike and the crack has increased substantially (it was merely a tiny scratch when I obtained it, obscured by all of the others). There is literally liquefied rust seeping out of the wound which has stained the paint and I need kiss it goodbye.

(I've now had three costly keirin frames fail in less than a year—methinks it is time to find another niche of the cycling world to hang my hat on.)

Thanks so much for your help—I needed a kind hand to guide me towards reality and yours was tender :)

The downtube is cracked, empirically. Thanks so much for the help :)

That's too bad. Do you know what kind of tubing it was made from? Some tubes are seamed and welded, even very good tubes, and the seam can split

In case some sees this in the future, you can apply oil from the outside and wipe it off. If it comes back, it's cracked.

The lovely thing is that in all of these keirin frames that I have which seem to be failing, this one actually has the decal on the seat tube denoting the tubing:
https://cimg3.ibsrv.net/gimg/bikefor...ab40bf012.jpeg

That being Kaisei 019.

Thanks. I have thought about getting some Kaisei, some people in the U.S. are using it.

Were your frames retired Kirin race bikes or new from builders? Seems like a string of bad luck.

These are all used frames, likely crashed and thrashed on the velodromes in Japan before I was given the opportunity to buy them... And then I use the frame like a 'daily rider' and they disintegrate beneath me....

I have purchased dozens of these keirin frames and work through them like napkins... This has been going on for years. I am now fed up with it: It is my dream to find a framebuilder who is willing to build me a lugged steel track bike with keirin geometry and aesthetics, bombproof with a threaded fork, but I haven't found that kindred soul yet... And so I keep buying these ****ed up keirin frames because I love how it feels to ride these things :)

That makes a little more sense. My understanding of Kirin frames is that they shouldn't hard to duplicate by a framebuilder. The geo is standard track geo and the tubesets aren't anything special, just NJS certified. I'm sure you could find someone.

It seems like I should be able to find someone, doesn't it? Though there isn't anyone—strangely. I am begging for it. Indeed, it is such an odd vacuum that I am considering taking up framebuilding myself... Who knows, perhaps there are others besides me who love riding track bikes on city streets.

There are lots of people in Japan that could build you a NJS frame. I just saw a post from Cherubim of a Keirin rider winning a race on one of their bikes. No idea how much they charge though. They usually display at NAHBS, so you could talk to them.

https://cimg3.ibsrv.net/gimg/bikefor...200541db23.jpg

Does this help?

https://alexscycle.com/products/panasonic-full-order-njs-track-frame-460-630mm

https://www.yellowjersey.org/panak.html

I don't have any experience with track bikes or track bike frames but am slightly confused at the replies. Is the frame toast?

If this was a regular steel bike I would strip the paint to fully expose the possible crack. I then would closely inspect the crack itself from the outside and possibly from the inside. If after stripping the paint I could not find the crack I would still try to Magnaflux the area, if this steel alloy is ferrous enough, to see if there is a hidden crack.

Oh... and if it really is a crack, then this frames a crispy critter...

He put oil in from the inside and it came out through the crack, so yes it's a crack.

Duane built a track frame for my son a couple of years ago. He uses it at the velodrome in Seattle, not on the streets. Duane is in Seattle and a member of this forum. Alternatively why not seek out a used track frame on ebay? I am sure there are lots of them, just not likely former keirin frames.

Ethet, this is a forum to exchange ideas on building our own frames. Why not build your next frame yourself? A track frame with .9/.6/.9 tubing (like the Kaisai 019) is an easy build. If you are not inclined to gather your own equipment, framebuilding classes like the ones I teach are available. You'll end up with a frame as nice as the ones a pro makes. And maybe nicer because you can spend more time with the details.

I'm a bit suspicious that part of the breakage problem of kierin frames is caused by overcooking the joint using brass filer. Some videos of Japanese builders show them getting a joint really hot. In the States we tend to use lower temperature silver as our brazing material. Of course frequent crashes undoubtedly contribute to breakage issues.

I don't think this one has anything to do with temperature. It's cracked right in the middle. I bet if you cut that tube out you could see a flaw in the tube.

It's my understanding that most Kirin frame that are sold used have been crashed and retired from racing. Doug is correct, there is nothing fancy or exotic about the tubeset used on a NJS cert frame. The NJS cert is nothing more than a standardization. The tubing used is what is recommended for a first time builder.

Weird that the crack runs lengthwise along the tube, much more typical for cracks to propagate around the circumference tube. Due to orientation of the crack, I think it would be a reasonable chance of success to repair the existing cracked downtube by drilling small holes at ends of the crack to halt propagation, notch along length of the crack with a cut-off grinder wheel, lay a TIG bead down in the notch, and then grind/file/sand the surface back to flat. Such a TIG crack repair could be done much cheaper than attempting to replace the entire downtube by un-brazing from the lugs.

Like I said:
I think if you welded it, you would end up with two cracks, because it's likely that the flaw extends to the ends of the tube . There is no point in stop drilling if you are going to weld the cracks, but in either case you have to make sure to pick up the ends of the cracks.

It is a strange crack. My first thought was they used seam welded tubing (like a Huffy). But, there could have been a flaw or wear on the mandrel when it was drawn.

I was curious if it's seam welded tubing, but too lazy to check. There are lots of good tubes that are seam welded and then drawn. Some of the high-end stainless, for example. Some tubes occasionally make it through with defects. The late, lamented True Temper tubing had a lot of such failures in the early days.

Vintage Reynolds 531 sometimes made it out of the factory with grooves cut on the inside that would fail like this. That tubing was pierced and drawn, no welding.

If so then it says something about the bike and its base materials we should not forget...

If it's true, then the builder should have looked. And Kasai should have looked. But it can happen to any of us that build, I think. Especially in a production environment.
I got burned by Columbus a couple of years ago. First time for everything, but I blame myself for not measuring more carefully before I put the frame together.