Kalloy Uno Ultralight.

[AMGRoadster]

I am 63.5kg. Given the experience of the shop and the mechanic that built the bike. Plus their reputation and the other builds I have seen. I have to take the position they know what they are doing. This is not a case of a hone mechanic, doing an install, and looking for someone to blame for issues.

If look at the failure point it is in the middle of the plate and not near the bolts.

[MagicShite]

I am 63.5kg. Given the experience of the shop and the mechanic that built the bike. Plus their reputation and the other builds I have seen. I have to take the position they know what they are doing. This is not a case of a hone mechanic, doing an install, and looking for someone to blame for issues.

If look at the failure point it is in the middle of the plate and not near the bolts.

that's kinda a fallacy of appealing to authority no?

From where I'm from, I've seen more home mechanics that are far more competent than the best shops you can find in my entire country.
(and in my experience they all suck)

Not looking for an argument, just genuinely interested in how they installed it.

EDIT: this is coming from a person who owns 10+ units of kalloy uno with mixed uses ranging from XC, Trail and Road with zero issues so far.

[AMGRoadster]

I am 63.5kg. Given the experience of the shop and the mechanic that built the bike. Plus their reputation and the other builds I have seen. I have to take the position they know what they are doing. This is not a case of a hone mechanic, doing an install, and looking for someone to blame for issues.

If look at the failure point it is in the middle of the plate and not near the bolts.

that's kinda a fallacy of appealing to authority no?

From where I'm from, I've seen more home mechanics that are far more competent than the best shops you can find in my entire country.
(and in my experience they all suck)

Not looking for an argument, just genuinely interested in how they installed it.

EDIT: this is coming from a person who owns 10+ units of kalloy uno with mixed uses ranging from XC, Trail and Road with zero issues so far.

Agreed on the home mechanic front. I know some awesome ones and I know some horrible mechanics and otherwise great bike shops.

My experience first and second hand from very knowledgeable people. Is that the mechanic that built up the bike is topnotch. That said I did not observe him build the bike and thus can't speak to the details.

Seems like I did a poor job attempting to impart key facts. When I made a reference to hone mechanics. It was not meant in a disparaging way. The point I was trying to make. Is that I was not the one to build the bike. I am not looking for someone or a company to blame for my *f##k*. My reference to home mechanics was directed at myself and not homd mechanics in general.

[robbosmans]

Looks to me like overtightened pinch bolts. Also how exacly did it fail?

[mikemelbrooks]

I looks to me as though the stem broke at the steerer end, also I believe that Kalloy went from advising equal spacing to no gap at top with later stems.

[Coolcat]

[...] Kalloy went from advising equal spacing to no gap at top with later stems.

So that means that one is supposed to tighten the upper steerer clamp screw until the edges of the clamp touch? That sounds like squeezing the steerer.

[robbosmans]

Not the steerer, the bars

[mikemelbrooks]

[...] Kalloy went from advising equal spacing to no gap at top with later stems.

So that means that one is supposed to tighten the upper steerer clamp screw until the edges of the clamp touch? That sounds like squeezing the steerer.

From page 25 if this thread. download/file.php?id=82843&mode=view

[garbageman]

That stem is clearly broken at the steerer tube end. What does it matter how the handlebar clamp was tightened?

[Attermann]

because there is a wrong and right way to do it?

[garbageman]

because there is a wrong and right way to do it?

How does the way in which the handlebar clamp was tightened (incorrectly or not) contribute to a failure on the steerer tube end of the stem?

[Attermann]

i think i just didn't look properly at the pictures

[rwoofer]

Normal aluminium is ductile close to breaking strength, so you would expect to see more bending or stretching of metal around the failure. That is why alu handlebars are generally safer than carbon,they rarely fail catastrophically. From the pictures it looks like either corrosion or fatigue induced catastrophic failure.

[AMGRoadster]

The stem did break on the steerer tube end. It broke in the middle, after the end of the bolts. It snapped when I hit a speedbump, aka a sleeping policeman. The stem was installed by a highly respected shop and had not been touched in several months. Except for an inspection/touchup ~1 month after the install.

I can only take the position that it was installed correctly based on the reputation of the shop and the interpretations I received of the break. I did not witness the install. As much as I would have liked to have the metallurgy tested for defects, fatigue, etc. It was simply too expensive given the zero to no chance I had of recouping my costs.

The stem was less than 1 year old and had no obvious signs of corrosion (to my eyes). Given the failure rates (in general) of aluminum parts on bikes vs. carbon. I am not sure why anyone would choose aluminum if there is an alternative. Those comments are confined to items such as crank arms, steerer tubes, handlebars, etc.

[MikeD]

The stem did break on the steerer tube end. It broke in the middle, after the end of the bolts. It snapped when I hit a speedbump, aka a sleeping policeman. The stem was installed by a highly respected shop and had not been touched in several months. Except for an inspection/touchup ~1 month after the install.

I can only take the position that it was installed correctly based on the reputation of the shop and the interpretations I received of the break. I did not witness the install. As much as I would have liked to have the metallurgy tested for defects, fatigue, etc. It was simply too expensive given the zero to no chance I had of recouping my costs.

The stem was less than 1 year old and had no obvious signs of corrosion (to my eyes). Given the failure rates (in general) of aluminum parts on bikes vs. carbon. I am not sure why anyone would choose aluminum if there is an alternative. Those comments are confined to items such as crank arms, steerer tubes, handlebars, etc.

I don't think I've ever seen a stem fail like your's did. Where did you buy it? Maybe it was a counterfeit if you bought it on ebay?