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Do you trust your handlebar stem?

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  • May 29, 2014 at 4:15 pm #21562
    SideBurn

    Riding home after a late shift at silly o’clock in the morning there was a loud bang; it was all I could do not to go over the front of the bike. It was dark and I had no idea what had happened. More to the point I was doing 30mph downhill. The bike swerved right, I hit the tarmac scraped down the road on my back, off the side of the road down an embankment and into a tree….. a downhill skier could not have done it any better 10 out of 10 for style =D>
    Once I had checked all my body parts were in the correct place, I looked at my bike….
    It appears that one of the two bolts holding the bars to the stem had snapped. The second bolt ripped out causing the handlebars to become detached…..
    Luckily I had some electrical tape in my bag, I re-attached the bars and rode home B-)
    Looking at the stem…. two bolts???? What was I thinking????? What a s**t design…. X(
    Maybe I am being a bit harsh; I have had this stem for some time and I have used it on unforgiving territory, or British roads as they are also known.
    Anyway; I have skin missing on my face, shoulder, hip and knee along with very colourful bruises on both of my thighs. Not forgetting the general aches and pains….. I am feeling very sorry for myself 🙁
    I am writing this just to warn others to look very critically at their stem and ask yourself is it fit for purpose?
    This incident could have been so much worse….

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  • May 30, 2014 at 8:41 am #796733
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    SideBurn

    Jimmy Ray Will wrote:ITM

    Jimmy Ray Will wrote:
    ITM Millennium!!! Isn’t that over 10 years old? I think that, right there is your problem.

    This is what I am thinking…. I cannot be the only one with an ‘antique’ stem 😕

    Muchos kudos for simply taping your bars back on and riding home… that is truly hardcore!

    Thank you B-)

    Get well soon.

    Mind you, it was a choice between ringing ‘er indoors at silly o’clock for a lift home….. or risk death with taped up bars….
    Not much of a choice really :S

    May 30, 2014 at 8:24 am #796731
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    Jimmy Ray Will

    ITM Millennium!!! Isn’t that
    ITM Millennium!!! Isn’t that over 10 years old? I think that, right there is your problem.

    Truth is the stem/bar interface is never going to be that brilliant from an engineering point of view… but things have moved on significantly from those Millennium days.

    Muchos kudos for simply taping your bars back on and riding home… that is truly hardcore!

    Get well soon.

    May 30, 2014 at 12:31 am #796729
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    giobox

    SideBurn wrote:I have to

    SideBurn wrote:
    I have to admit I did not use a torque wrench, but I am not a ham fisted bugger.

    When I used a torque wrench for the first time I was very surprised at how little pressure the 4 to 6nm most stems (in fact most bicycle bolts) spec is. If you’ve never used one, there is a good chance you will be surprised at how much you are over-tightening everything on your bike. It’s worth having a quick shot of one to get the feel.

    May 29, 2014 at 10:36 pm #796727
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    SideBurn

    I have to admit I did not use
    I have to admit I did not use a torque wrench, but I am not a ham fisted bugger. Obviously they could have been over or under tightened. But as I have said they have been fitted for some time. I am wondering if the bolts could have become brittle through use? Work hardened? So maybe I should have changed the bolts?The stem is an ITM Millennium, but now it has broken I think it looks a bit flimsy…
    Thanks for the responses 😀

    May 29, 2014 at 9:56 pm #796725
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    stuke

    I had a stem faceplate fail
    I had a stem faceplate fail once due to corrosion, it’d done a couple of harsh winters.
    A big tug on the bars pulling onto a roundabout at rush hour and the faceplate disintegrated leaving the bolts in situ. Luckily I rode no handed across the roundabout like a boss carrying the bars, more luck than judgment mind 😉

    May 29, 2014 at 9:00 pm #796723
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    arfa

    Would you be able to name the
    Would you be able to name the brand ?

    May 29, 2014 at 8:09 pm #796721
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    drfabulous0

    Two bolts is a poor design as
    Two bolts is a poor design as you now realise, if they are not tightened evenly then one can be taking excessive force, four bolts or one are better. I’ve seen a few failures like this though, threads stripped and cracks and even once a stem shear off at the weld, luckily none of these resulted in injury but poor manufacturing quality was the issue in all these cases rather than incorrect installation.

    I’ve been a bike mechanic for many years and I have to warn you guys not to put to much faith in reccommended torque settings, it is not uncommon to do up stem bolts to the manufacturer’s specification and find that the bars will slip under a slight load. An experienced mechanic can not only make a fair estimate of torque without the torque wrench but can also feel when the bolts are under sufficient but not excess tension.

    May 29, 2014 at 7:47 pm #796719
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    southseabythesea

    Ouch! I could add to that do
    Ouch! I could add to that do you trust your LBS, when I got my cross bike home I gave it the once over and found that the headset bolts were loose even though they insisted giving it the once over before I took it home. Always check ’em with a torque key, bike shop or not.

    May 29, 2014 at 7:10 pm #796717
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    glynr36

    Perhaps you should title this
    Perhaps you should title this ‘Do you trust your bolts’

    The stem didn’t fail the bolt did, most likely due to over torquing it.
    The second came out due to the abnormal load on it more than likely.

    Invest in a torque wrench.

    May 29, 2014 at 5:38 pm #796715
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    Gasman Jim

    I used to be a fan of the 2
    I used to be a fan of the 2 bolt Thomson X2 stem…. until the faceplate deformed and wouldn’t then grip the bars sufficiently to stop them rotating forwards when correctly torqued, (and I’m only 71kgs).

    I now use the 4 bolt X4 stem on all my bikes. Much more secure.

    May 29, 2014 at 5:03 pm #796713
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    Al'76

    Not criticizing, but did you
    Not criticizing, but did you mount the bar using a torque wrench? Could see this happening if the bolt was done up silly tight, but like to think it would not happen under normal circumstances….

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