Bent rear derailleur hanger Airborne titanium frame

Last August I purchased an Airborne Titanium bike on eBay. The bike has been perfect until today, with only a few minor issues which were easily corrected. Today about 2 miles into a ride I suddenly felt the pedals stop and a great deal of resistance in the rear wheel bought me to a stop. Fortunately I was slowed by traffic just starting out as the light changed, so I was only going about 10 mph when this happened. Right after this occurred, I noticed one of the derailleur pulleys on the road. The rear derailleur somehow got caught up on the rear cluster. I really have no idea how this occurred. I've been riding for over 3 decades and never had something like this happen.

The bad news is the rear derailleur looks pretty damaged. The worse news is the derailleur hanger is bent out of alignment. If I had to guess how much, I'd say between 5 and 10 degrees. I tried bending it back with a small adjustable wrench but this didn't work much, if at all. I've read conflicting accounts on bending titanium hangers. Some people say you can do it, others say you risk cracking the frame. I'm reluctant to use more leverage. Would hammering it back into alignment be a better course of action? Note that this hanger is 1/4" thick. It's beyond me how it could have bent in the first place. The forces involved just didn't seem that great. The rear wheel was only out of true maybe 4 or 5 mm after the incident.

Any advice on how to proceed would be appreciated. And does anyone know an inexpensive source for Dura Ace 7800 rear derailleur parts? Specifically, it looks like I'll need to replace B-tension adjustment screw, one of the pulley bolts, and the inner plate. One of the pulleys looks a little chewed up but I could probably grind the burrs off so it's useable.

I just had this happen on my Giant Reign 2 mountain bike. Derailleur busted, hanger bent. Most hangers are made of a softer material so they bend before your frame does.

I wouldnt try to bend it still attached or you risk bending your frame. You need a new hanger (assuming it is removable?) for YOUR FRAME. Local bike shop should be able to help if you take the old one in. Not sure on repairing the derailleur, I just bought a new one (sram x7).

Hanger should only be like $10 or so. Have a look here if you like - http://derailleurhanger.com/airborne.htm not sure which model Airbourne you have?

Is it a 10 speed rear? A few on the bay... http://www.ebay.com/sch/i.html?_nkw=dura+ace+7800+rear+derailleur

Derailleurs usualy come in short, med or long. Make sure you get the right one. If you have triple chainrings up front and 10speed at the back you will almost certainly want the long version.. Good luck, its a pita. Mine happened because a stick flicked up into my chain and mullered everything.

PapaLumen said:

You need a new hanger (assuming it is removable?) for YOUR FRAME. Local bike shop should be able to help if you take the old one in. Not sure on repairing the derailleur, I just bought a new one (sram x7).

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The hanger isn't removable, the theory being that it's so thick it really shouldn't bend. Unfortunately, that theory was just proven wrong.

BTW, the bike is an Airborne Torch. The material is 6/4 titanium.

Is it a 10 speed rear? A few on the bay... http://www.ebay.com/sch/i.html?_nkw=dura+ace+7800+rear+derailleur

Derailleurs usualy come in short, med or long. Make sure you get the right one. If you have triple chainrings up front and 10speed at the back you will almost certainly want the long version.. Good luck, its a pita. Mine happened because a stick flicked up into my chain and mullered everything.

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Yep, 10 speed rear. Dual chainrings (39/53) in front, 12-23 in back.

I wish I could figure out what caused this. There were no sticks or other debris in the area. I didn't do anything different as far as shifting goes. One minute, everything is fine, next minute, there's pieces of bike on the road. The only good thing I suppose is it didn't happen at speed or the rear wheel almost certainly would have been history.

Take the bike to a qualified bike shop. They should have a tool to align the hanger so that it is parallel and plumb to the face of the frame's bottom bracket. I did this procedure dozens of times when I worked in a bike shop, though never with a Ti hanger. Most high end frames typically have a removable hanger.

Not removable, ouch. Ah, a road bike.. like this? - http://www.tirides.com/wp/wp-content/uploads/2011/05/airborne-torch-hanger.jpg
damn looks pretty sturdy, i can see how you're surprised it bent. Maybe the top pulley wheel got too close to the cassette somehow.. is the cassette ok, no bent teeth?

Looks like a tough job to straighten for someone who knows how. Good luck, sorry I cant be of assistance.

Yeah, that's what it looks like. No bent teeth on the cassette. I was hoping someone had a safe method to bend it back using tools I might have handy. Going to a bike shop to fix this is out of the question. For starters, I'm not sure if I'd trust them. And for what it would cost, I could buy the tool and attempt the repair myself.

On another note, I'm wondering now if it's actually bent, or if this is just how it was made. If you look at that picture you linked to, the hanger actually looks bent relative to the dropout. Unfortunately, I never took any pictures of that part of the bike before this happened. I suppose I could put a replacement derailleur on and see if it shifts OK.

Here's the tool:

Park Tool Derailleur Hanger Alignment Gauge - DAG-2

If you do a lot of your own repairs it may be worth owning. It's unfortunate that you don't have a shop that you trust. For avid bikers, having a relationship with a local shop can be very beneficial. In the shop I worked in "regulars" routinely enjoyed discounts that were not offered to the general public.

I've learned to do 100% of my own bike repairs for financial reasons, so I've never really established any kind of relationship with the local bike shops. The one shop I did trust went out of business years ago when the owner passed away.

What concerns me more at this point than the cost of the repair is why this happened in the first place. Is the particular rear derailleur I had prone to this sort of problem? What would I need to do to keep this from ever happening again? If this had been some sort of freak thing, like a stick getting caught, then I wouldn't be so concerned. It just seems to have happened for no good reason I can ascertain. Since it seems the replacement parts I need to fix my derailleur aren't readily available I'm probably going to go with the Shimano 105. I just can't afford a replacement Dura Ace 7800 and the derailleur tool right now. In fact, I'm kind of annoyed I need to spend anything on repairs so soon given that the bike cost me $1325 and I've only put 687 miles on it.

Do you have another bike available? If you do, check the relationship of the hangar to the frame. I might be wrong, but I think that the hanger should be parallel to the wheel. The hanger will not be 'straight' with the frame. After all is said and done, the problem might just be a broken rear derailleur.

If you do have to bend, put the frame in a vice as close to the hanger as possible.

I took a look at my bike here in NY. It is not Titanium and the hanger is a separate aluminum piece attached to the frame. It does not line up with the frame and it appears bent when looking at it and the frame at the same time. It does look to be parallel to the wheel. That makes sense to me. The hanger should be parallel to the wheel and the cassette.

will said:

Do you have another bike available? If you do, check the relationship of the hangar to the frame. I might be wrong, but I think that the hangar should be parallel to the wheel. The hangar will not be 'straight' with the frame. After all is said and done, the problem might just be a broken rear derailleur.

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The rear derailleur is definitely bent beyond repair. Just eyeballing it, even if the hanger were aligned properly, the cage looks way off. Another thing I just noticed is scuffing on the derailleur bolt area. I didn't cause this because I've never fallen riding this bike. Apparently the bike did fall at least once on the derailleur side prior to when I bought it.

I also tried a spare derailleur just to check the alignment. The hanger is definitely about five degrees out of alignment in both planes. Not severely, but enough to be noticeable. I suspect this happened before I bought the bike, but I never noticed. A fall on the derailleur side easily could have caused this. It didn't affect shifting much, although I did have minor problems occasionally upshifting. Bottom line-the hanger may have been out of alignment before this happened, and this in turn may have caused the problem in the first place. The way the hanger is bent, the bottom of the derailleur cage may have bounced enough during a downshift to catch the spokes. It looks like I'll need to align the hanger then, and also purchase a rear derailleur (the spare I just tried is 1980s vintage and not really functional).

It looks to be worthwhile getting the alignment tool, so I'm ordering that today. The hanger on my Raleigh has been out of alignment from the time I owned the bike but not enough to severely affect the shifting. I can fix both bikes now.

If anyone sees a good deal on a short cage rear derailleur (105, Ultegra, or Dura-Ace are all OK), please let me know.

Thanks everyone for the help!

jtr1962 said:

....
What concerns me more at this point than the cost of the repair is why this happened in the first place. .....

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My only experience of this type was caused by the chain failing. A side plate came loose and caught in the derailleur cage. The derailleur was drug around the cassette as I continued to pedal, and eventually was driven into the spokes, bending the derailleur hanger. Not a pretty sight! The fact that the chain was still jammed in the derailleur was a pretty good clue as to the cause. I could imagine that a less severe chain failure might have caused your problem, but there should have been some sign. Maybe some debris got caught up in the chain and jammed up the pulleys? I've seen a friend get a stick flipped up by the front wheel that then jammed in the rear wheel and tore out the derailleur.

I ended up buying the Park derailleur alignment gauge, figuring it was no more expensive than taking the bike to a shop. For indexed shifting, you really benefit from having an accurately aligned derailleur hangar. My only concern is with the titanium. Ti is pretty tough and springy stuff usually. The Park tool provides a lot of leverage that might be needed to spring the hangar far enough to take a set. It might not hurt to check with Airborne (now renamed to Van Nicholas) and see what they suggest.

Steve K.

I saw something similar happen to a buddy's bike a few weeks ago. A stick pushed the rear derailer into the spokes which then completely bent everything and broke a couple of spokes. Usually the hanger is removable and softer on purpose. I guess the idea is that it is cheaper to replace a $10 dollar hanger than a $100+ derailer. I am guessing it is not a big enough problem for road bikes so they don't have a removable hanger.

Steve K said:

It might not hurt to check with Airborne (now renamed to Van Nicholas) and see what they suggest.

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I contacted Airborne support yesterday. Here is what I wrote:

I bought an Airborne Torch last August secondhand. I recently noticed that the rear derailleur hanger is a few degrees out of alignment. I'm not sure why. I've never crashed this bike, but the prior owner may have. I'm thinking of realigning it with a Park Derailleur Alignment Gauge (DAG-2 ). Would you recommend against doing this? If so, why? If the repair can be done, would there be any specific procedure you recommend following? Note that we're talking about a pretty small misalignment here, probably less than 5 degrees. Any help would be greatly appreciated.

Here was their one sentence response:

I'd take it to a pro shop and have them do it.

Reading between the lines, this is telling me it's possible to bend it back using the DAG-2 tool since this is what any pro shop would be using.

My only concern is with the titanium. Ti is pretty tough and springy stuff usually. The Park tool provides a lot of leverage that might be needed to spring the hangar far enough to take a set.

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It's my understanding that the dropouts on a titanium bike are pure titanium to facilitate bending things back into alignment. Pure titanium has good "cold formability", which basically means it can be bent without cracking. Since pure titanium has about 1/4 the yield strength of 6-4 titanium, the dropouts are made much thicker to compensate.

Any thoughts on all this? Buy the tool and go the DIY route, or just buy a derailleur and leave the hanger alone (it looks like it'll shift tolerably well given that it's only a few degrees out of alignment)? Forget the bike shop doing the repair. The nearest pro shop is over 5 miles away. I'm not walking a broken bike that distance, walking back, waiting perhaps a week until they tell me it's ready (the shops here are all too busy to do repairs while you wait), then walking the bike home. That's 20+ miles, about 5 hours, of walking, half of them with a bike in tow. Bikes aren't allowed on buses here (and there's no direct route to the bike shop by bus anyway).

As you are not prepared to take it to a shop (understandable considering what you have said), I would get a new derailleur and see how it is and keep a close eye on everything.

Shame about the limited response from Airborne, they obviously assume everyone can easily get their bike to a shop. If the new derailleur doesnt go well then I would still go the shop route no matter the inconvenience as it's a job they probably have some experience with and may not charge a lot to do it. It does sound from what you are saying that the hanger despite being non-removable is made of softer stuff to facilitate bending/straightening, this makes sense.

I do prefer to do most jobs myself but this is one I wouldn't personally tackle. Up to you.

I managed to successfully bend the hanger back. I got the brainstorm today that the rear axle bolt might be the same size as the derailleur bolt. Turns out it is. I took an old rear wheel, screwed one side down tight into the hanger, and then proceeded to bend the hanger back. It required surprisingly little force. First I did it by eye, seeing if the axle of the spare wheel and the axle of the bike's rear wheel were aligned in both planes. After that, I held an adjustable wrench right up against the braking surface of the rear wheel and rotated the spare wheel to see if it remained in contact with the braking surface as I rotated the spare wheel. I needed to make a few minor adjustments. This probably isn't as good as I might have gotten it with the derailleur alignment tool, but it looks to be no more than maybe 1/8" deviation. That translates to alignment to within 1/2 degree-probably plenty good enough for things to work well. Bottom line spare rear wheel=poor man's derailleur alignment gauge!

I'll know for sure if I did it right once I install a new derailleur. I'm still looking on eBay.

Sorry-double post.

did this to my all 6.4 Litespeed Tellico whilst eating a big stick with my rear wheel.
no one knows why the dropout bent, the derailleur should have self-destructed around it.
2 people reefing on an R tool could not get it to bend back. 6.4 ti tube bike with 6.4 dropouts.
needed a new dropout welded in by Litespeed. 400 bux and 2 months later I got that bike back.



even though you bent it back yourself, it is critical !!!! to have it checked with an R tool. it has to
be exact or say goodbye to easy riding and staying in gear. that chain will jump all over the place
if that dropout is 1 RCH off in any direction

I'm 100% sure the dropouts on my bike were are titanium. I agree if they were 6-4 there's no way I could have bent it back. 6-4 is stronger than most steels.

My game plan going into this was to forget it if the hanger didn't move fairly easily, the theory being if I apply too much force I risk cracking the hanger off. I'm glad my dropouts weren't 6-4 or I likely would have been in the same position as you. Now at least I know why the hanger bent in the first place-it is fairly soft. I'm totally puzzled how your 6-4 hanger could have bent. I would think the derailleur bolt would snap long before a 6-4 hanger starts bending.

I obviously won't know if the alignment is off until I get a derailleur. What I plan to do it install the derailleur and see how it shifts. If all is well, no problem. If not, at least with the derailleur installed I could carefully ride it to a bike shop to have the alignment adjusted instead of walking it there. For what it's worth, even though I have no pictures proving it, I think the hanger was somewhat misaligned when I got the bike. The indexing on the bike worked fine pedaling forwards but pedaling backwards sometimes jumped gears. This doesn't happen on a bike where the alignment is perfect. Also, the force required turn the pedals by hand backwards seemed excessive.

Be sure to check the max derailleur travel adjustments especially towards the spokes. Maybe the stop adjustment was too far out and allowed the derailleur to run into the spokes which, in turn, bent the dropout?

I'll definitely be checking derailleur travel even though I think the more likely cause of this mishap was either a loose or broken derailleur pulley shaft. I'll need to make sure I regularly check the pulley shafts henceforth. I recall shortly after I starting using the bike that one of the pulley shafts was very loose. Fortunately I noticed it while truing the rear wheel. Maybe it worked itself loose again?