First, I want to thank the individual who sent me this stem, genuinely thankful that there are nice people out there who wish to help. This thread is in no way meant to be unkind to you for your action.

I had posted a thread a while back about wanting to play with some handlebar positioning. A member here was nice enough to send me a free adjustable stem to use. It was a cheap one out of a bin, no huge investment from the person who sent it to me, nor the company who made it. I looked it over and figured it would work well for me to use with varying bar position from +/- 30*. I installed it, following the directions included for the order of operations and to torque spec.
Any time I install a part, like a stem, I will test it pre-ride by stressing it in every direction I possibly can by hand. In this case I grabbed a handful of bars and twisted and pushed every direction I could. The stem, nor headset made any noises and everything looked good.

My son and I went out on a ride around town and I noted about five miles out that the handlebars/headset area started making this really weird noise. At the point we were, there was no easy or quick way to return home. I pulled over and took a look and noticed that the pinch bolt for the adjustable part of the stem had somehow loosened up. It seemed really odd, especially since there is a lock bolt in addition to the pinch bolt....but the handlebars were moving a noticeable amount. With no one available to come get me I decided to just continue home at an easy pace.
Part of the way is a mile long steady uphill grade where it is nearly impossible not to torque the handlebars a bit. As i am heading up the hill (and this is a State Route as well, lots of traffic for about a mile) I hear a creak and snap and the bars fall towards the front wheel. Lucky for me I was still able to turn, but the bars were completely loose up and down. I had no upper body support at all and getting home was quite the challenge.

Turns out that the pinch bolt and spacer mechanism in the adjustable part of the stem snapped in two spots. I suspect that my wrenching on the bars post install may have caused a hairline crack to form which was then completely broken when I started leveraging them up the hill. Downright scary as hell, and I don't recommend trying it.

Glad you weren't hurt, I have bad mental pictures of a horrendous crash with you going over the front into the asphalt. Could you at least tell us the brand of the stem that broke? Not to embarrass the good person that sent it to you but so we can know to look for problems.

Actually, no trash day already came and went, so I don't have the backing card. It seemed fairly robust, with the only design fault I saw and was concerned about was that both of the steerer tube pinch bolts were on the same side. I figured if there was a fault that it would have occurred there.

On the positive, I did find that 30* + will require a very long stem to clear my knees while standing to take off.

I had a quill stem get loose. Suddenly I couldn't steer.

baby bike bolts fail

the other day i was supposed to "take my time" while biking to a friend's place, and the first 3 miles of my ride away from home i rode with no hands. yes, i was on the sidewalk, so avoid unnecessary lane intrusion. i just kind of wanted to see how long i could do it, since i'd given my friend the idea of a "hands-less race" before.

i DID have to touch the handlebars once at a particularly nasty rain gutter, but that was it. fun stuff.

I never rode without handle bars but once I rode without a bike seat...it did not feel good.

Do whatever you want man, but if I were you, I wouldn't be bragging on the interwebs about how I doubled my potential for disaster.

had a saddle bolt bust off once, I was soooo glad I kept my rack on. falling onto a MTB tire at 20+ mph would have been a soprano-ing experience.

Thats happened to me before, when when I was younger my parents had bought me a wally-world bike, after 50 miles total (sevaral rides around 10 miles) I decided to go further, one day I went 29 miles planned, I made it 6 miles and while doing a short climb my handle bars bended and broke right at the stem. This is why x-mart bikes are bad.

I once rode with my hands off the bars on the MUP for about 1.5 miles. A guy passed me the other direction and said "nice!"

True dat!

Oh, Thanks. After reading that my boys have gone into hiding and I probably won't be able to coax them out for a couple of hours.

And they get stollen.

It was a Trans X brand. I am not embarrassed, but I am a bit bummed. I bought 3 of them from a salvage store that buys out stock from places that go out of business and such. I think I paid 3 bucks apiece for them just to have in the spare parts bin. I sent it to the OP in hopes that it could help him locate the sweet spot in stem rise, so that he could get a good stem configured that way.

Sorry, I wish it had worked out. I put one on my daughter's bike and it has worked well so far. I better inspect it thoughh. Thanks for the heads up.

No apology needed, it was REALLY cool of you to do for me. I suspect the issue would have shown itself in the other one(s) you have as the failure was right into the start of it's first usage. I think when I pulled over the first time that the break in the bolt had already occurred and what was the apparent loosening I felt. There was a very distinct noise from the onset of failure that sounded a lot like a too loose headset creak.

This will give me nightmares.

Keep riding to maintain peace !

I was riding a hybrid bike on dirt trails and hit a bump and the stem kind of collapsed and the front wheel goes off track suddenly. If I'd been going downhill it might have been pretty spectacular but it was just a sort of graceless fall.

Snugged it up enough with my multi-tool to finish the ride but later tightened it up with a liberal coating of Loctite on the bolt. Still have the bike - this was about 15 years ago - and I don't think I have touched that bolt again.