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  1. #1
    RoadBikeReview Member
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    Is this Stem cracked or is it a defect or deep scratch?

    I was just inspecting my bike and saw this on my stem. Hard for me to tell if its just starting to crack or what. If I run my nail along it i feel a little groove.

    Its an aluminum stem on my jamis ventura sport. I was inspecting it because I am going on a few long rides this weekend away from home. Is it okay? Its not like to other scratches that are on my stem.
    Attached Thumbnails Attached Thumbnails Is this Stem cracked or is it a defect or deep scratch?-img_1649.jpg   Is this Stem cracked or is it a defect or deep scratch?-img_1650.jpg  

  2. #2
    Not a rocket surgeon.
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    Hard to tell. Tale it off and look on the inside. If its cracked it will be on the inside also.

  3. #3
    RoadBikeReview Member
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    would it always crack right through? I took it off and checked and didn't see anything along the edge or on the other side. Worth noting that right where the mark is the stem straightens out a little bit. Its hard to describe but its not a perfect circle and has like a squarish part to the top. That line actually goes along the squared part. You can't see it but you can feel it from the inside.

    Sorry if it sounds a little confusing. As you can tell this is not my strong suit

  4. #4
    Cranky Old Bastard
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    Some more pics would help. I'm having trouble picturing where the cracks are.

    Alloy stems aren't layered, meaning that they don't usually get surface cracks.
    "When you know absolutely nothing, anyone who knows 1% more than nothing sounds like an expert."

  5. #5
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    Sorry that's the best pick I can get. The area I'm worried about starts at the spacer and works its way down right near the middle. You can see a little sliver scratch and it extends a little bit into the black. I know there are a few scratches but its the one that you can see indents into the black surface.

    It's fairly small but don't know too much about this stuff. Don't think it's a crack but what else could it be? Also of it is a crack how dangerous is it? Can it be monitored or does it news to be changed immediately?

  6. #6
    Carbon Fiber = Explode!
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    Paranoia much? I really don't see anything there. They just look like normal wear and tear to me.
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  7. #7
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    Here's what I would do: Take the stem off and look at the edge of the stem-the portion which contacts the spacers. You might see the crack there if it's through the thickness of the aluminum. If that edge of the stem is black as well, it might help to sand off the paint/anodizing, but be aware that the sanding might smooth out any crack, making it more difficult to see.

    The other option is to paint over the suspected crack with visible paint such as white nail polish. Some hardware stores sell paint called "tamper proof torque marker". Brush some on the area. If it, or the nail polish cracks, then you have a crack underneath.

    You can also try what's worked successfully for me: Remove the stem and place a piece of scotch tape on the inside of the stem opposite where the suspect crack is. Press it on firmly; it may help to clean the are with alcohol first.

    Next, saturate the outside of the stem around the suspect crack with Liquid Wrench. If the crack is through the aluminum, it will creep through and stick to the tape. You may have to give it an hour or so after spraying it for the brown fluid to creep through the crack but if there's a crack, the fluid will stick to the tape. Worked for me.

  8. #8
    RoadBikeReview Member
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    It looks like a scratch to me, but do the Liquid Wrench trick described above to be safe.
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