905

Simply put: have you ever had a titanium frame crack? If so, was the problem sorted to your satisfaction, either with a repair or a replacement? And did it discourage you from further ti purchases, or a particular manufacturer?



(I've written about my own experience here.)

sumgy

Cracked my Blacksheep and it took James nearly 2 years to get around to repairing it for me.
If I break it again it will become landfill.



I am doubtful I will ever break my Moots, but if I do I am sure I will be looked after.



Why do you ask?
I know a number of people who are onto their 2nd and 3rd CF frames in 12 months. This is a big part of why I wont ever buy a CF frame.

905

I asked because it happened to me, and though I know ti isn't indestructible (particularly the welds), I simply wasn't expecting it. Hasn't put me off ti, though I won't be able to justify another one for a while...

sumgy

Do you mind if I ask the manufacturer, and where it broke?
My Blacksheep broke at the drive side chainstay, and the story I was told was that the wrong tubing was used.

905

Enigma, near the bottom bracket. Pictures at the link in the OP. Speaking of which, pity your pics have gone missing, at least for me – ti is easy on the eye.

sumgy

Hmmmm sorry, I don't know anything about Enigma to comment more.

905

The comments I was after were your own experiences; thanks for posting.

CliffordK

Sorry to hear about you bike woes, and I'm glad you got it put back together.

Ok, so you've had the bike for about 5 years, and done "many thousand miles". What does that mean exactly? 5,000 miles? 25,000 miles? 100,000 miles?

A road bike should be able to handle A LOT OF MILES. Are you riding it as a Fixie? That may put unique stresses on it that many road bike riders don't do... I.E. You're climbing hills in high gear, and using the bottom bracket for brakes.

I ride vintage steel. Not a lot of miles each year, but it does add up, since I bought the bike 34 years ago, and it was already a dozen years old when I bought it.

I've just started experimenting with different materials. My winter bike is a bastardized Titanium frankenbike. I've always fought with the front derailleur to get enough lateral throw. But, it does mean that I get flex chain rub in certain gearing combos. But, so far nothing has broken other than the rivnuts. It does seem, however, that I get a lot of flex chain rub in the higher gears.

Broken Titanium frames do show up on E-Bay every once in a while. I've intended to try my hand at welding/repairing titanium.

My guess is there needs to be a little more engineering than just welding 8 tubes together. The Carbon Fiber and now Aluminum frames are getting engineered up the wazoo, but maybe not the small shops. I have acquired a Titanium Colnago that has a badly broken seat tube, and have considered using oversized tubing to replace the broken tube, and/or gussetting the bottom bracket joint. We'll see what I end up with eventually.

905

I guesstimated 20,000 miles, or "just warming up". It's a singlespeed and gets a lot of hills thrown at it, so I did wonder if the bottom bracket was extra stressed because it sees a fair amount of grinding. It's freewheel, so extra braking forces aren't an issue.

Light years beyond my skill set. Good luck!

CliffordK

So, on an ordinary multi-speed bike, that would be the equivalent of one frame every 2 or 3 cassettes, And you could still be working on your first set of chainrings.

I just hope that isn't the kind of disposable future we're heading into.

sumgy

To put that into some form of perspective, I have a friend on his third Trek frame in 2 years and he estimates he has done 6000km on each frame.

CliffordK

3700 miles?

Whew...

Crash damage? Or just wearing out?

That sounds like.... grind through one pair of tires, and buy a new bike. It is time for some changes in either bikes or riders.

shelbyfv

I looked at your pics and it appears they just welded over the cracks in the seat tube. Is this correct? I would be very disappointed if this was my bike. It may be OK structurally but it sure looks crappy. I wonder if that tube was compromised from the start? I can understand a crack at the weld, but that seems different.

Marcus_Ti

No kidding.

My 7 is headed for 20,000 miles mid-next year. Still going fine.


Sub-4K miles is just silly wasteful barring accident. Either he has a ton of money to blow on fashion, or abuses his equipment. Or both.

CliffordK

Looking back a the first photo, it looks like the crack starts at the downtube, then travels along bottom bracket/seat tube weld on the right side back to the chain stays, then crosses straight across between the stays, with maybe a little splitting.

The weld should fix the problem. However, it is a good question to ask what caused the failure.

Titanium is supposed to be touchy with heat and contamination. Or, potentially cumulative fatigue. None of which will be fixed with the repair. Do they have a heat treating facility?

I wouldn't be surprised if the failure returns in 20,000 more miles. Hopefully after some good use though.

sumgy

Just broke.
No crashes, no hard racing.
BB cracked on one and the chainstay snapped when he stood up to pedal on the other

DXchulo

Hasn't happened to me, but I saw it happen to a guy on a brevet back when I lived in Ohio. He somehow managed to finish the ride.

You might find the latest CyclingTips podcast interesting: https://cyclingtips.com/2016/12/cycl...stom-builders/

One of the hosts mentions that he had a Ti bike break at a weld going downhill at 40mph. Long story short: Ti is more difficult to work with than most people realize and smaller builders might not do safety testing on their frames.

shelbyfv

One of the things that gave me confidence when buying my Lynskey was their pre-bike experience fabricating titanium for industrial applications. There is some nasty stuff out there, nobody wants it to leak.

905

Correct.

Agreed not too pretty, but then I don't know how pretty welds ever are.

I think the tube was compromised from the start, which makes the weld a kind of band aid – though perhaps that simile is unfair. I assume it's a very strong band aid.

They are one of the few (maybe the only?) firms making at least some of their ti frames in the UK. They also do a lot of repairs on other ti bikes.

CliffordK

I don't spend a lot of time admiring my bottom bracket welds. Perhaps a Top Tube weld near the headset would be different.

I suppose the issue is the asymmetry in the welding, but I don't think it particularly looks bad as the repair was done.

The fear is that if the tube was compromised at the time of manufacture (undersized, or poor welding), then it is possible that it is still compromised.

joejack951

For contrast, my Pedal Force mail-order direct-from-Taiwan carbon fiber frame has around 25,000 miles on it without issue. Cost me a whole lot less than a similar Trek or Seven.

rpenmanparker 

Doesn't anyone care why metal frames crack at the welds? Two interesting questions:

* Does this happen less with welded steel or not?
* Does (did) it happen less with brazed, lugged frames than welded frames.

And finally, I wouldn't be surprised if the goal of ultra-neat, minimal weld lines didn't contribute to the problem. Lots of folks praise the "craftsmanship" of Ti welders who can produce a very thin, beautiful weld line that ALMOST looks like it has been filed. It makes me wonder whether the sloppy, generous weld line isn't actually a lot stronger. Is craftsmanship about making something beautiful or durable?

unterhausen

it happens less with steel, mostly because Ti is a lot easier to screw up. Sloppy welds are a really good way to have fatigue cracks. I would much prefer a neat weld, although there certainly is a level of neatness that is good enough.

I think a lot of Ti failures happen because builders are trying to keep the weight down.

I don't really count it against Ti, but I had a couple of Teledyne Titans crack at the bb shell. That's a very highly stressed joint, as it happens. I don't count it against Ti because it was made with commercially pure Ti, which is never used nowadays. It's very soft. But it's the reason I don't own Ti bikes, so maybe I do have a bias.

CliffordK

The question on the weld line would depend on how it is cracking at the weld line.

One would really have to separate the weld to see where the crack is on the inside of the joint.

• Poor penetration. Just a bit of weld scabbed on top. Crack will go through the weld, and then the original joint will fall apart.
• Too much heat. Titanium is supposed to be sensitive to heat. So, crack may travel along edge of weld, through new material.
• Weld Contamination?

Now, if you look at densities and strength, one has: Aluminum < Titanium < Steel.


To compensate, one does the opposite with tubing thickness: Aluminum > Titanium > Steel. Thus, one also naturally sees bigger welds on Aluminum than other materials. I haven't welded Titanium yet, but aluminum is odd... I find steel much more forgiving of a material to work with. But there is a reason for fluffy aluminum welds.



There are plenty of reports of failures in steel, including failed lugs, and failed dropouts. And, of course, bends and crash damage.


I assume big companies like Colnago that makes (or has made) Steel, Titanium, Aluminum, and Carbon Fiber bikes carefully track the failure rates in each frame type. And hopefully makes improvements as issues crop up. It is interesting that I believe they no longer produce titanium frames, and may not do aluminum either. But still produce lugged steel and CF. Unfortunately, I doubt they'll ever publish their internal test/failure data unless they can prove it makes them better than other companies.

gsa103

Ti is notoriously difficult to weld. That's why all the failures are at the welds. Aluminum is more difficult to weld than steel is Ti is much more difficult to weld than Al. Ti is very sensitive to contamination and you need a very well purged environment. For critical applications, they have weld chambers to ensure than the entire part is in an oxygen-free environment.

You could build bike frames out of Schedule 80 Ti pipe, and they'd still crack at the welds. Thicker tubing might be even more prone to weld failure because of weld penetration issues.