Hmm, to me it doesn’t look like a classic failure from incorrect brazing tbh. Ok, maybe the fillet on the bottom of the joint could have been a bit bigger, but it wouldn’t have made a huge difference I think.
It looks more like a failure from just overloading the tube’s cross section, since it is the tube that failed, not the joint. The headtube is also very short, which results in higher tension in the tubes than with a longer headtube.
Have you maybe cased a few jumps on your trip, or is the head angle on the slacker end of the spectrum?
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What tube was that?
Even if the filet was not perfect and could have been a stress riser, it held up
@Luniz82 I was trying to find the specific tube I used. All I remember is that at the time I bought the tube almost 2 years ago, it was the longest butted 34.9 mm tube I could find. That narrows it down to either .9-.6-.9 or .8-.5-.8
I appreciate the feedback on this. I rode this bike quite hard. I’m not sure what I should expect for how long a frame should last when ridden hard. It’s a 150mm fork. The head tube is quite short and the head angle is quite slack. 110mm and 63.5 degrees. I am going to remedy that on the next bike I build, but I would like to repair this one. What would you recommend to use for that? larger diameter? thicker wall?
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Wow. 34.9 is tiny for a 150mm fork 63.5ht!
I would have used the Velospec 38mm 1.0-.7-.9 butt ( AC38100709-800). For our production bike in Taiwan, we have a 38mm 1.4-.75-1.0 downtube. That is what I would use for a 150mm fork!
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yeah. I learned all sorts of lessons from this bike. I never did any courses or classes and I probably should have. Just mess around with tubing and a torch and learning by experience. I built this bike before this Forum was a thing. I was originally planning on a 140 fork but I stole this 150mm pike from my coworker. I don’t think I really meant to ride it as hard as I have, but it’s been so fun. I sold my Full Suspension Carbon bike because all I rode was this hardtail.
I’ve got some devious plans for the next bike though.
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Any idea on how to get hands on a tube like that outside of taiwan?
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Reynolds have a 38.1 x 1.2-0.9-1.2 853. I believe this was made for another builder but they will sell them on request, so I’m told.
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Velospec make similar yubes as well.
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You can reach out to ORA. They will sell to framebuilders. They form their tubes based on their production, so they may or may not have it in stock.
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While you’re at it, maybe consider biasing the DT decals towards the top of the tube, rather than on the sides like you have 'em. Not essential but it is tradition. Most people looking at a bike are looking slightly down, so you want the DT decals facing slightly up.
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Coulda been worse - I worked for one framebuilder that put the chainstay cable stop on the wrong CS, and did the entire paint without noticing until it came out of the oven.
The second time I saw this kind of thing was while working for Larger Framebuilder #2. They managed to get a Road Test write up in a major bike mag, and then sent off the bike frame with NO chainstay cable stop. Total ridiculous nightmare involving numerous sets of eyes that missed THAT one. The magazine was quite forgiving and took photos that didn’t show the clamp-on cable stop that they used (well except one small pic). The magazine was no doubt trying to sell advertising space and they didn’t want to alienate a potential advertising buyer !
EVERY single framebuilder has a few skeletons in the closet. There isn’t enough space on the Internet to list all of MINE, LOL.
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I just had a frame finished ready to go out to teh customer with an $1800 paint job on it ad I noticed I forgot to put teh rear caliper mount on it!
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I thought I heard someone swearing! (Here in the Netherlands…) Damn, that’s even more painful than one of my first frames where I realised I put the BB in wrong after it came back from paint. (something a nice discount and a generous amount of loctite could fix)
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That’s what happens when you are under the pump to get the frame finished while trying to pack and move 1600km
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That’s wild! looks like a BFS headtube?
Yes or from the same manufacturer anyway.
From my understanding, they swaged/formes raw material to close dimensions before machining.
To me that’s where the culprit is, something must have happened at this stage of the process on this particular headtube…to prove my point the same dude has ridden the replacement frame I made for him with the same headtube for the last 8 months no issue at all, the frame just broke last week from a classic failure at the downtube gusset,
But That’s the price of riding intensively 7 days a week
After this, I bumped the wall thickness to 2.5 mm in my own headtube and so did Andrew at BFS.
I did a top tube replacement on a fairly traditional road bike for a builder who was very polished in their bike designs and finish work. Someone who hangs out here regularly used to build them (HA!). The builder’s business partner saw the repaired frame and couldn’t really tell that the lugs had been repaired/remade which was nice that I got the curves right but then he said ‘wait, you forgot the pump peg on the back of the headtube’. Ugh, my heart sank. Luckily the customer was forgiving and said he never carries a pump and always uses cartridges! I have often thought a final QC checklist would be a useful last step. Maybe @Bulgie will chime in to say what they use to do as I imagine it was fairly rigorous.
You’re talking about Davidson of course. Through almost the whole time I worked there ('84-'94), I made all the customs, and a team of maybe 3 to 5 others made the production bikes. I don’t remember any checklists, other than with customs, the order form had a list. We all just knew, from repetition. Make a few thousand of something, you tend to get decent at it.
Though this was 30 to 40 years ago (grain of salt), I honestly don’t remember any BOs left off, mostly because with few exceptions they were put on bare tubes before they were put in the tacking jig. Speaking of the production models, if you have a box of 10 or 20 DTs and one is missing a BO, it’ll stand out like a [insert tired cliché here]. On the customs, I guess I was just good at remembering them all (or lucky), 'cuz I can’t remember a single one — or a tandem 
— that ever needed repainting to add a missing BO. Of course I could be forgetting.
I did have to make a new fork once, for multiple National Match Sprint Champion Ken Carpenter, who was leaving that day for the Seoul Olympics. I made the fork right, but the mechanic assembling the bike cut the steerer exactly one cm too short. Pretty sure the paint on the second fork was still off-gassing when Ken and his bike got on the plane later that day. (He lost in the 1st round though, oh well.)
We tried to make BOs all pretty fool-proof with dedicated fixtures for each BO, but some fools can defeat even the most foolproof systems. For example our H2O boss drilling fixture put them in the exact right place every time (I thought), but one day I was walking by a frame being worked on by one of our less-sentient builders, glanced at the H2O bosses in passing and said “those are too far apart”. He scoffed but then measured and they were 65 mm instead of the spec 64 mm. My eye-crometer was so dialed-in to 64 mm spacing that a silly millimeter was obvious to me. How he got the tube to move in the fixture between the two holes I dunno, plus we “always” dropped a pin through the drill bushing into the first hole after drilling it, before drilling the second hole, so this dufus had obviously skipped that step. That’s two errors, and you had to make both of them to have a frame come out wrong. (I count not noticing as a third error.) He was later fired, not because he was inept but because he was also dishonest. Bill had a tolerance for mistakes, but not dishonesty.
Another sad story, a FB there had an early 753 Merz, beautiful frame, but he didn’t like the 26.8 seatpost, wanted to use a 27.2, so he started in with the adjustable reamer. Again I was just walking by and saw something you never want to see, the blades of the reamer visible on the outside of the seat tube below the lug. He was too young to have ever learned that early 753 tubes were metric, 28.0 mm OD not 28.6. Poor guy didn’t even know he’d ruined the frame until I came along to tell him to stop reaming. He was able to remove the dearly departed ST, open up the lug and the BB socket and put in a 28.6 Prestige ST, so the frame lives on. That’ll be a hard one for future bike historians to figure out, like did Merz sometime mix inch and metric tubes on one frame? Oh well there are bigger mysteries in this world.
At a previous place of employment, a co-worker was making a tandem and didn’t have a long enough steerer so he used a shorter one, that he inserted only halfway into the crown. On a tandem. He cut another piece and put it in the bottom half of the crown to hide what he’d done. The inevitable happened, people were injured, I think there was a lawsuit or threat of one, but it was all hushed up, no one spoke of it. That guy was still working there when I moved on! It’s so hard to find good help…
Needless to say, tandem steerer is not a place to cut corners. You could end up like this guy:
“Hetchins” actually made by Bob Jackson. BTW the incident was seen by credible witnesses who agree, it was not crashed, it’s a true JRA, though he may have hit a pot hole while using the front brake. The steerer turned out to be unbutted, not even strong enough for a single let alone a tandem. I have several photos of failed BJs in my Hall of Shame folder of FB fail pics. Friends don’t let friends ride Bob Jacksons. I think I heard they went out of business, but not soon enough if you ask me [cat noise].
My painter and I just had this discussion the other day about creating a tick list for my process. It is defnitely a should do not a maybe.