aivkov

Just registered to post my first question, I am a regular cyclist, doing on avg. around 60 miles per week, with occasional long rides. I had the carbon bike bought from BikesDirect for 7 years and generally enjoyed it, but today I had a little accident. When starting to climb uphill the steerer's tube snapped leaving me tumbling in the middle of intersection. The part is made of metal and it looks like aluminum.

If I had to approximate, the bike has about 7000-10000 miles on it, but from reading internets it appears that aluminum has incredible fatigue life so I am baffled at what happened. Was it due to me potentially over-tightening the stem clamps around the steerer tube? Has anyone had that happen to them?

3alarmer 

...aluminum steerer tubes have a long and troubled history in the world of the bicycle. Not sure what you mean by aluminum "having incredible fatigue life", but of all the materials ffrom which to make a high load, multiple shock impact portion of a bicycle like the steerer, aluminum is the least suitable material because of its tendency for fatigue failure.

You should check and see whether there's ever been a recall on your fork. They might send you a new one for free. There's a whole section that lists various recalls here.

Andrew R Stewart 

As mentioned Al has a significant fatigue failure mode. Maybe do some research on non bike websites for real metallurgical understandings, our community is too full of ego and hope for marketing to not "fudge" facts.

Frames/forks are just another component and needs periodical service. At the minimum a break down, cleaning and look at. How often? That's the $64,000 answer. One clue is that the less the fatigue life of the material, the larger the load is, the rougher the "roads" are the more frequent this service stuff becomes.

At one time a lifetime warranty was the standard for frames and forks. As AL and carbon have become the majority of frame materials the warranties have also "evolved". I suspect that any written warranty has been long expired but good customer relations are sometimes more important then written words. Give the seller a call but don't hold your breth.

As to what caused the failure? I'd have to see the bike/fork/stem to say for sure. However there are a few paths to what happened. Overtightening the stem pinch bolts is down the list. Andy

Bike tinker man

I would try & look very closely & see if there were any small cracks there originally that you may have not noticed, one assumes you have never crashed it ?

KraneXL

Aluminum is more likely to bend than break. However, there are many different alloys from low to high quality so you didn't mention the type and/or the bike. Whenever I hear of metal snaping the first thing that comes to my mind is Made in China.

hokiefyd 

It may not matter, but can I ask for clarification? The title of the thread mentions handle bar and stem (external to the bike frame), but the post itself mentions the steer tube (mostly internal to the bike frame). To the original poster, what part actually snapped? Did your steer tube (the uppermost part of the fork that passes through the frame's head tube) actually snap in half? Or is this the stem, the component that mounts to the top of the steer tube and extends forward, holding the handlebar?

Your post says the component snapped when you started climbing a hill, which might suggest to me that it was the stem (external to the frame), as if it broke when you stood up and started leaning on the bar one way and then the other.

HillRider

Aluminum can bend in a single hard impact. Fatigue failure is usually sudden and looks like a brittle break. Aluminum, what ever its source, is subject to fatigue failure.

DiabloScott

It does sound like your failure was fatigue. Fatigue ALWAYS starts with an incipient crack (it's the very definition of fatigue failure), and then proceeds through cyclic stresses - which are almost always present with bicycle parts.

So it's very likely that your stem or steer tube had a crack and that you probably nicked it somehow either by over-tightening or trauma from a crash or something. Once you get that nick, fatigue will proceed no matter what your material is. Steel does not offer you any protection from fatigue.

The different fatigue property that aluminum has, is almost certainly not the way your component failed. This is the one you'll hear people pontificate about though.

Fatigue failure is something you have to watch out for no matter what metal you're using, no matter what component is using it. When that incipient crack happens somewhere you can't see it, it will proceed to failure before you know it's there.

Kapusta

Without some clarification about what exactly snapped (steer tube or stem) and where exactly it snapped, speculation on this is mostly pointless.

3alarmer 

CPSC List of Bike Fork Recalls

...nothing I can see in there from Bikes Direct. You should report your experience to the company and the CPSC. I only just now discovered that my ancient Bianchi Randonneur has been subject to a fork recall because of three instances of crown and blade separation (all steel fork). So all of us probably ought to be more aware of the current condition of any fork on a bicycle than we seem to be.

My impression is that few bikes that are recalled actually make it back to the dealer for a fix. Mostly aging and product life cycle takes care of them.

T-Mar

Based on the submitted photo, it is the steerer tube and appeared to snapped at the interface between the top race and stem or spacer. Unfortunately the picture isn't great and isn't doesn't show the complete failure but it looks like a possible fatigue crack before it tore apart. Picture assist:

Arthur Peabody

I broke the handlebar stem of my Schwinn Typhoon 50 years ago. I was pulling at the time, so I straightened up, holding the bars over my head, for a surreal second before I fell. I was young and invulnerable then so I remember no pain, only surprise. It was steel of course, probably the cheapest. It had about 30K miles on it, mostly delivering newspapers. Put a magnet on your stem to see if it's magnetic. How much weight do you save?

HillRider

Interesting list and it goes back as far as 1985.

Few bikes that are recalled make it back to the dealer or manufacturer probably because bike recalls get almost no publicity. Unlike auto and major appliance recalls where every TV news service and newspaper spreads the word loud and long, bikes are almost completely ignored. Also, I don't think bike manufactures have customer records they way car makers do.