Titanium - strong enough?

OK, so titanium is meant to the wonder metal - strong and light. We know that it can undergo 50,000 zillion flex cycles without busting - see the pivotless designs like the Moots YBB .

But - it is strong enough for really mission critical applications? I ask for views, because of an accident I had last week. I was riding home on my Ti road bike with Ti bits. Stomped on the pedals to pull away from the lights and the two Ti bolts holding on the front of my Ti stem both sheared :shock: , and I ended up in a crumpled (and not quite run-over) heap in the road, holding the now disconnected handlebars .

That, and I've got a crack in the Ti at the bottom of the groove at the top of the seat tube.

Am I too strong for Ti, (or too fat)? Or, is this a fact of life with fancy materials?

if the titanium has a crack then its busted my friend.it has a strange property such that it is very strong as you know but when it fails it does it catastrophically ie no bending just snapping.it has the same property as mmx aluminium frames wth ceramic composites.under the microscope they are very much the same.if you were lucky enough to find some one who can weld tit frames the heat from doing it would probably distort the frame anyway.

there was a thread running a few months ago about this here with some photos of sheared Ti forks etc. See if you can find it - might be an eye-opener! :shock:

gibbleking":2va2xbxv said:

.if you were lucky enough to find some one who can weld tit frames the heat from doing it would probably distort the frame anyway.

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and why did the original welding not distort the frame? sure such cracks can be fixed by welding. Ti bolts are not a good idea, even less on Ti parts.

really, it is not the material it is what the builder has done with it. plenty of poorly made Ti frames and parts around just like with any other material. is it a frame from a reputable builder?

Carsten

Carsten

You're right - the frame is a Torch-alike from XACD in China, which I picked up for rather few notes when I was working in China three years ago.

I do know a Ti welder (does work for Omega), so I will give the welding a go on the crack. Also, no more Ti bolts!

Jules

Much to the horror of quite a number of retro bikers on here, I got a Ti frame that had a stress fracture patched up, so I don't think it is a def. right off.
The Gary Fisher is still running if a bit uglier

The chap was great, sent him some pics in the first instance and he fixed the Gary Fisher for not much money really.


Might be worth a look?

http://www.vernonbarkercycles.co.uk/

Ti isn't as 'strong' as steel, you cannot just swap a steel bolt for a ti bolt without losing some strength. This goes for ti pedal spindles, BB spindles and all those other applications where the dimensions are already fixed.

stevet1":46mm6ag8 said:

Ti isn't as 'strong' as steel, you cannot just swap a steel bolt for a ti bolt without losing some strength. This goes for ti pedal spindles, BB spindles and all those other applications where the dimensions are already fixed.

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Funny thing is...people swap out the steel for Ti all the time without thinking about it. Same goes for alluminum bits too. You see alloy anodized bits all over people's bikes, in places that there should never be anything but good old steel... :shock:

I went out for a long ride the other day and wondered what all the creaking was after a while and the ano alloy chainring bolts had all undone themselves and one had even fallen out

Think I'll stick to steel, never happened to me with that :shock:

or get some threadlock...

It just takes people a while to get their head around the qualities of different materials. I work in the aircraft world and it takes some people ages to accept that aircraft are made of Aluminium because it is easier to form into shape, rather than it doesn't rust (cause it does, sort of) and it is lighter (which it is not necessarily, because even though it is less dense you need more of it for the same strength).

All materials are different and an original component will be of a certain spec. Change the material and the component may behave differently, including failing when least expected. The posts above are spot on, one can't always change the component, save the weight and expect it to be as good as the original.

I like steel or chunky aluminium, can't stand this hydroformed stuff, just does not look right! As for Ti - can't afford it, therefore it is rubbish and I don't want it (that Funk Ti is not in my Ebay watched items at all!).