I hit the edge of a cone yesterday when biking and had a pretty hard fall. Was looking at my bike to see what damage it took. Saw this crack on the rim, is this something really serious that I should be worried about? Last thing I want is to take another hard fall

This is the bike I have. https://archive.fujibikes.com/2010/Fuji/roubaix-acr-20

enter image description here

  • You have rim brakes - does the brake track bulge out at all here? I've written off a rim on a pothole, it was pretty obviously distorted, both visibly and to the touch.
    – Criggie
    Commented May 27, 2021 at 23:37
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    I suspect the 'crack' (see answers as to what it is) was there before the fall and you only just noticed it.
    – mattnz
    Commented May 28, 2021 at 3:22
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    The wheel (or at least this part of it) is fine. The “crack” is just where the two ends of the rim are joined together.
    – Michael
    Commented May 28, 2021 at 7:00
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    As @Michael stated, this is probably the rim joint. If it's exactly opposite the valve stem hole and there's an identical "crack" on the other rim wall that lines up exactly with this "crack" (look closely - it might not be as easily visible), it's the rim joint. If it's not exactly opposite the valve hole and there's no corresponding "crack" in the rim wall on the other side, it's a real crack and the rim is toast. Commented May 28, 2021 at 12:34
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    On the contrary to what the other says, it is clear to me that you need a new pair of rims, possibly carbon, they must be very expensive. And, since you had a fall, it is time to thinking about buying a new bike, if you did not think about it already. I am kidding. Bike is likely to be fine, the rim is absolutely fine (it is not a crack, it is from the manufacturing process)
    – EarlGrey
    Commented May 28, 2021 at 19:19

3 Answers 3


It may be worth glancing at this more detailed answer that discussed how aluminum rims were constructed. But in brief, aluminum rims are first extruded in a flat bar, then they’re cut and rolled into hoops, then the ends of each hoop are joined somehow.

One method is to simply pin the ends together without smoothing out the joint. Your rim was built this way, and you’re looking at the seam where the ends were joined. Basically, this is there by design. Look in the corresponding location on the other rim and you should also find a seam.

On higher end rims, the joint is usually welded together and the weld is sanded down. For practical purposes, I believe that the advantages are mainly cosmetic. On pinned rims like yours, you might sometimes feel a bit of a pulse when braking (assuming rim brakes, which you have) when the brake pads pass the seam.

If you hit an obstacle, a more common failure mode would be for the rim’s bead hooks to get dented or to buckle. Rims that crack are more likely to do so around the spoke holes. If the rim cracked so as to look like a seam, I suspect the crack usually won’t be straight. If you can’t find on your bike’s spec sheet that your rims are pinned (may not always be obvious, including on the rim manufactuer’s site), this is one indicator I’d use to differentiate a crack from a pinned rim. Also, a crack may not propagate all the way through a rim, and you can check the other rim to see if there’s a seam in the same location. The photo below, from a different question, looks like it could be a crack rather than a rim seam.

enter image description here


I suspect the rim will be just fine based on your description.

A cone is presumably an orange plastic road cone, which are fairly soft and squishy.

You as the rider had a hard fall, but the bike's wheel rim was already on the ground, and probably did not take much of an impact.

As long as the brake track is still flat, your rim is fine to ride.

If your tyre didn't puncture, its not a hard-enough impact to bend metal.

Just remember to check your rims periodically when doing monthly maintenance, and if things change, then stop and reevaluate.

  • 1
    Agreed. For periodically checking wheels: Just lift the bike off the ground, spin the wheels and check that they run true (less than 1mm of sideways or up-and-down wobble of the rim, relative to the brake pads).
    – Michael
    Commented May 28, 2021 at 7:02
  • @Michael yep - even better is to lift the bike and spin the wheel lightly, then see it gently coast to a stop, no quick deceleration as the brake pad rubs the rim bulge.
    – Criggie
    Commented May 28, 2021 at 7:50
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    +1 for mentioning that anything that would damage the rim pretty much has to give you a flat tire, which I concur with but didn’t explicitly state.
    – Weiwen Ng
    Commented May 28, 2021 at 11:20

This is a seam from where the rim was manufactured. You are safe. There is no possible way a crack would be perfectly straight. Check other rims ( even new ones ) and you will see this seam.

  • 1
    Welcome to Stack Exchange! This isn’t strictly true, as higher-end rims tend to be welded and then machined smooth, and the rim joint is a lot harder to find. Otherwise, good summary of points raised elsewhere.
    – Weiwen Ng
    Commented May 31, 2021 at 16:28

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