This happened to me with a really shitty Fake S5 I got from China. I had some folks look at it, but the cost to fix it was going to be throwing good money after bad (>$500). What type of frame is it? Do you have warranty recourse?

Ha. It's the dengfu FM098

I've had for about 20k miles and have been thinking about replacing.

Now might be the time

I'm surprised no one else has ever had this issue

That issue shouldn't be common as that is not correct way to design a dropout. A drop out should be structural metal all the way through and then bonded into seat stays. Just for reference there are some decent shots of a standard design here: http://www.reduxracers.com/...ized-tarmac-sl3-pro/

Also it would appear on your frame the bolt which attaches the hanger to the dropout go through the carbon which is another engineering disaster waiting to happen. Carbon+metal equals galvanic corrosions which you really don't want at the dropout. Any decent frame will actually have a fiber glass protection core separating the carbon the metal at these critical junctions to prevent the corrosion and help the carbon-metal bond. Granted you often can't see the fiber glass but its another reason most dropout will not look like the one you posted.

Would you stop riding the bike given the photos / design flaws you called out?

You are missing a metal washer in the spot where carbon is wearing out. I have this issue on my shiv - washer keeps falling out during wheel changes and I keep putting it back.

I've got a BMC SLR01 with about 36,000 miles on it that has the same issue. First I had trouble getting into my smallest cog, then some wheel/cassette combinations would rub on the frame. I "solved" the issue by using a washer on the hub to push the hub/cassette away from the dropout. Not the best solution for quick wheel changes...

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Kevin

http://kevinmetcalfe.dreamhosters.com
My Strava

Can you please post a photo where the washer is supposed to be?

Have you gone back to BMC to warranty the frame? I found a few past threads that this was an issue on Giant bikes, and those folks were able to exchange the bike to mfg defect.

That is a full carbon dropout, you are missing no parts.
Poor clamping skewers, bad habits when fitting wheel and not fully seating the wheel every time lead to this.

Use the replaceable dropout as a guide and build the front of the U shape back to where it was to get things aligned.
Build up the indented part to flat on the inside.

And strong two part epoxy will do.


Be wary of indoor trainers.

Eh, lots of high end frames nowadays have full carbon dropouts. Felt does on all non-thru-axle frames. Giant does on it's higher end frames (SL framesets only).

And I don't think DengFu is made at Giant or ADK (like Felt). So your results may vary with who has the carbon technology to make your frame. The material isn't the problem, it's the choices you can't see, like carbon grade, layup, resin content, and bonding that matter here.

This is what I was referring to (pic of a venge, shiv has similar construction):

https://goo.gl/images/5hkPAv

As some posters have already pointed out, yours may be a full carbon drop out, so this may or may not be relevant to your situation.

Do they really make dropouts like that?

I have seen the Felt drop outs like the ones on the AR here: http://m.feltbicycles.com/...g/product/1/10169493

Cervelo has made a similar design but I'm pretty sure this style of hanger ensures the wheel doesn't direct contact (and potentially erode the carbon). Hanger doubles as a hybrid dropout and still supports the wheel. As with the photo of the shiv I though there was always a metal barrier between the frame and the QR.

Most high end road bikes have a full carbon drop out on the the non-drive side with no metal plates on them, and then a full carbon drop out with holes (gasp) to attach a metal replaceable derailleur hanger. Cervelo has been doing it for a while, Specialized, Felt, Giant... most high end brands.

There's some variation, but you can see it on Felt's AR series that has carbon on inside, hanger outside. The FR has a hanger that slides over the frame and is actually both the internal and external contact for the wheel. Giant's TCR has an internal hanger with an outside contact that's carbon (Adv SL frame, the lower frames are metal dropouts bonded into frame).

The AR, FR, and TCR SL frames all have 100% front fork dropouts for sure. That's pretty common on most bikes now, but some brands still use metal inserts for the lower end frames.

Cervelo has a carbon interior interface on their new R series. It's faced and notched for wheel contact, so I'm going to assume it's a functional interface with high strength plies. I didn't check the old ones, but probably the same there.

The photo shows a common solution lots of manufactures use. Pinarello does the same thing with the F8.

So there's lots of ways to make a dropout, but I wouldn't discount a carbon dropout just because it's carbon. Well-made frames tend to be...well-made.

Besides wheel shifting, which I can mostly solve with a tight skewer clamp, is there any risk of riding the bike?

If you have a problem getting the wheel to stay put, the safest answer I can give you is don't ride it. Especially if I can't work on your bike. Not worth the risk to tell you it's safe. If a tight skewer doesn't fix the problem by itself, you might have other structural issues with the frame.

Tight skewer will never fix it, that photo shows appreciable wear and it needs to be repaired.
Replace the hanger, fill in the carbon.