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Old 04-27-07, 01:50 PM   #1
strykerhorse
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Broken Front Derailleur standoff

Hello all,

I've broken my standoff for my front derailleur, and I'm wondering if it's a common occurrence. If so, would I go about fixing it with some JB-weld, or would I need more professional help. I ride an 05 KHS Flite 900.
Pic is up.



Thanks.

Last edited by strykerhorse; 04-29-07 at 04:34 PM.
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Old 04-27-07, 01:57 PM   #2
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I'm not sure what you mean by "standoff". Do you mean the arm the cable is clamped to or the clamp that attaches the derailleur to the seat tube?

In either case, it's probably not repairable and, except for exotics, front derailleurs are relatively cheap. See an LBS for a suitable replacement.
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Old 04-27-07, 02:30 PM   #3
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Please be more detailed

Do you mean the "braze-on" bracket on the frame (which can be a misnomer because sometimes they are riveted on)? If so, did it come off in one piece or did it crack in pieces? If it came off in one piece, you can have it rebrazed or reattached with rivets. I wouldn't trust epoxy to hold up for very long. Another option would be to remove any residual weld or partial bracket with a hacksaw and/or file, repaint the area, then get a clamp-on front derailleur bracket that adapts a braze-on FD to a frame that doesn't have a braze-on bracket.
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Old 04-27-07, 02:41 PM   #4
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I just looked up the KHS web site and the Flite 900 is a carbon frame with high-line components so I think Steve has it right. The broken "standoff" is probably the bolt-on/glue-on front derailleur mounting tab, not part of the derailleur itself as I first guessed.

I agree that an epoxy bond is not likely to survive very long and re-riveting is necessary assuming the mounting area wasn't badly damaged. If it was and the rivets can't be replaced, the frame probably needs to go back to the manufacturer for repairs.
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Old 04-27-07, 04:27 PM   #5
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In re: to HillRider's comment, the 05 Flite 900 is not a carbon frame; it has carbon seatstays and a carbon fork. The rest is aluminum.

Mr. Katzman, thanks for the vocabulary correction. I was meaning the derailleur mounting tab/braze-on bracket. The derailleur itself is bent up, but I know that's a relatively easy replacement. The tab sheared closest to the chain, and as the chain ran by, it bent the front derailleur.

I'll get pics up ASAP to clarify my issue.
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Old 04-28-07, 12:24 PM   #6
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Quote:
Originally Posted by strykerhorse
In re: to HillRider's comment, the 05 Flite 900 is not a carbon frame; it has carbon seatstays and a carbon fork. The rest is aluminum.
OK, KHS must have changed the frame composition but kept the same model designation after yours was made. I looked at the 2007 product line and the Flite 900 is defined as:

Frame: KHS Carbon Fusion w/replaceable derailleur hanger.

In this case the "replaceable derailleur hanger" refers to the rear derailleur.

For 2007, you have to go down to the Flite 700 series to get an Al frame with carbon seatstays.

Even with an Al seat tube, an epoxy bond is not likely to be sufficient and the rivets should be replaced if the metal is still intact.
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Old 04-29-07, 04:35 PM   #7
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bump
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Old 04-29-07, 05:09 PM   #8
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Send it back to K2. They may give you a new frame, but will certainly have the best fix.
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Old 04-29-07, 06:40 PM   #9
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The photo helps a lot. The welded on front derailleur mounting tab is broken and the seat tube isn't round so the "fix" of getting a clamp-on replacement fd won't work either.

I agree that returning it to the manufacturer/importer is your best bet.
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Old 04-29-07, 09:31 PM   #10
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Due to the fact the seat tube is not round... I concur with HillRider. By the way, how long have you had this frame?
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Old 04-29-07, 09:40 PM   #11
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ask your local LBS if they know someone in your area that can weld on a new one. KHS is all made in taiwan. The only thing they will do is tell you to buy a new frame as it is not a manufacturers defect. after the weld job you wont have much paint around the weld and will need a repaint. Might be beter off finding a new frame anyways.
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Old 04-29-07, 10:18 PM   #12
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Quote:
Originally Posted by mtnbiker4791
The only thing they will do is tell you to buy a new frame as it is not a manufacturers defect.
I would say that this could certainly be considered a manufacturing defect. From the OP's description it seems like he was "just riding along" and it cracked. That seems like a defect to me.

Let us know when you/your KHS dealer gets some more info. I'd like to see the outcome of this.
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Old 04-29-07, 10:18 PM   #13
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First I would contact KHS, probably your best bet is to go into a shop and have them call (it usually works better in your favor than if you called yourself).

If no dice on frame replacement, you'll have to find someone that can weld alumnium.
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Old 04-29-07, 10:19 PM   #14
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In the photo I see a boss for an unused water bottle mount on the seat tube. I would try to make a mounting bracket for the front derailleur that attaches to the water bottle mount bosses.

Below is a drawing of what I have in mind. The water bottle holder on the down tube could still be mounted over the bracket if longer screws were purchased at the hardware store.

The materials are of 1/8 inch strap iron. The section that holds the derailleur mount is wider to give added strength and avoid flexing. Notice that there is a spacer between this section and the piece mounting to the bosses on the seat tube. You would need to file off the broken mount as much as possible so the new mount could take the same position as much as possible.

Begin by making the pieces to mount to the bosses. Attach them to the bike. Mark, cut, and fit the wider piece. Make the spacer to fill the gap. Hold these in place and tack weld them one at a time. Remove them from the bike and complete the welds. Do not cut the slot for the screw to mount the derailleur until the piece that will have the slot is welded to the wide piece. (There is less liklihood steel will melt and blow away in welding.) Cut the slot by drilling holes next to one another. Use a cutting wheel on a Dremel tool and a file to turn the individual holes into a slot.
Attached Images
File Type: jpg FD boss mount.JPG (12.2 KB, 8 views)

Last edited by twobikes; 04-30-07 at 07:38 AM.
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Old 04-29-07, 11:46 PM   #15
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Quote:
Originally Posted by strykerhorse
Hello all,

I've broken my standoff for my front derailleur, and I'm wondering if it's a common occurrence. If so, would I go about fixing it with some JB-weld, or would I need more professional help. I ride an 05 KHS Flite 900.
Pic is up.



Thanks.
First, that is kind of rare occurence, but not unheard of. JB weld is not going to hold up, IMHO.

I would just carefully bend the braze-on back in place and get someone to do a repair weld on it. That's certainly worth a shot. Any decent welder should be able to do this and it should only cost $10-15, at most.

While it's not certain, your braze-on is probably steel. See if a magnet will stick to it. It's worth knowing and you will need to know the answer to that question to get it fixed.

Your bike frame was designed for a braze-on FD and it does not look like you could go to a clamp-on type (due to a non-round seat tube), so you don't have a lot of options, short of sending the frame back to the manufacturer for repair.
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Old 05-01-07, 08:45 AM   #16
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Quote:
Originally Posted by 55-11
Due to the fact the seat tube is not round... I concur with HillRider. By the way, how long have you had this frame?
I've had this frame for almost four months now.

Quote:
Originally Posted by cascade168
I would just carefully bend the braze-on back in place and get someone to do a repair weld on it. That's certainly worth a shot. Any decent welder should be able to do this and it should only cost $10-15, at most.
I'll bend it back tonight and look into that weld ASAP. I'm getting antsy about not riding....
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Old 05-01-07, 08:54 AM   #17
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How did you break it in the first place?
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Old 05-01-07, 11:05 AM   #18
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Quote:
Originally Posted by cascade168
While it's not certain, your braze-on is probably steel. See if a magnet will stick to it. It's worth knowing and you will need to know the answer to that question to get it fixed.
I'd be very surprised if the tab were steel on an aluminum frame since the two metals can't be welded together and the tab is very obviously welded on.
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Old 05-02-07, 08:01 AM   #19
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You may be right but...

Quote:
I'd be very surprised if the tab were steel on an aluminum frame since the two metals can't be welded together and the tab is very obviously welded on.
How can you tell the difference between a weld and a braze from a photograph? It is certainly possible to braze a steel tab to an aluminum frame tube.
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Old 05-03-07, 02:20 AM   #20
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Quote:
Originally Posted by Ziemas
How did you break it in the first place?
To make a long story short, I broke it while trying to chase a car with jeans instead of shorts on. The pant leg got caught in the chainring/chain and pulled my leg with it, snapping the braze-on and ruining my front derailleur.

Mea culpa...time to start saving for another derailleur, and time to start running again anyway
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Old 05-03-07, 10:01 AM   #21
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Quote:
Originally Posted by Steve Katzman
How can you tell the difference between a weld and a braze from a photograph? It is certainly possible to braze a steel tab to an aluminum frame tube.
Looking at the picture I see a very obvious bead around the base of the tab. I've never seen brazing (except intentional fillet brazing) done like that so I'm pretty sure it's a weld.
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