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Discussion Starter · #1 ·
I've had this problem breaking hangers on two bikes now. A giant warp and now a specialized hardrock. And don't tell me my deraileurs aren't adjusted right because I've had my lbs install a brand new one...I snapped the hanger riding slowly in my driveway. I'm about to throw my fricken bike off a bridge!!!!!!
 

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Discussion Starter · #4 ·
I'm not even shifting half the time when it happens! And there are no sticks in my driveway. I run the stock 3x8 gearing with a long cage Lx deraileur. Everything else is stock and yeah the wheel is seated correctly.
 

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Torque me. Make me spin!
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Chain too short?

Is your chain too short?

If your chain is too short when you go big ring, big cassette cog, you can stress the derailleur hanger. On rear suspension bikes you have lengthen the chain to allow chain growth as the bike runs through the supension travel. So a correct length chain in the bike stand may not be the correct length when the suspension is squished.
 

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You don't happen to have any enemies with hacksaws, do you.

Seriously, if you still have the broken pieces, do they have a "breakaway notch" where they are designed to break? Does the LBS need to use a derailleur hanger tool to allign these when installing them?

Also if you have the broken bits see if you can look at the fracture and tell if they seem to be ripped backwards or sideways as they broke. If you can read the direction of the fracturing force it might give you a clue as to what's happening?

Don't chuck the bike yet, this must br frustrating but with a bit of careful detective work ypou can get to the bottom of this mystery.
 

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Rather than just assuming the LBS is correct lets get somemore of the symptons and look at a few things.

Are you typically in a certain gear when this happens?

Were doing something similar on both bikes when it happened, if so what?

Do you get any rubbing noises from the FD or RD?

If you pick up your rear wheel and pull the RD cable (actually pull it with your hand all the way, don't use the shifter) while spinning the crank does the RD go into the spokes? If it does the LBS didn't setup your RD properly...

Anthony
 

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Discussion Starter · #15 ·
Im typically in the granny up front and 1,2,3,or 4 in the back. most of the time it happens when i am just riding along. although the last time a was doing a wheelie. the chain does rub on the FD when im on the big ring and one of the smaller gears in the back. No the RD will not go into the spokes. im to the point where i turned in the low adjuster so far i cant use the biggest cog in the back, as i figured that would stop the problem. It didnt. im thinking its just poor hanger design but its gotta be more than that. i know there are aftermarket companies that make stronger stainless steel hangers, but would it help. im not gonna drop $40 on a stainless hanger just to snap it the next day.


-oh yeah they do break when im just riding along most of the time, but also every single time i bunny hop or jump it snaps. Would a better(sronger+stiffer) deraileur help? Im fricken stumped and so is every shop within an hour of my house, along with every rider i know.
 

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So its snapping for a reason, the hardrock is a good platform and it shouldn't just snap on pavement - I wouldn't go for a stronger (more expensive) part until you know why the current one is breaking.

When the LBS adjusted your RD did they check that hangar was straight?

Do you have pictures of your setup?
 

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Discussion Starter · #17 ·
i dont have pictures and cant post them because i dont have a computer or a camera. im doing all this on my ipod touch. they installed a new hanger with the deraileur. Any chance the frame was damged the first time it happened(i had the stock acera deraileur on at the time) and now thats causing it to snap? the frame does look worn down along the spot where the frame meets the hanger.
 

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I'm in the bike biz so I hate to tell you this, but don't assume that the mechanic at the LBS always gets it right. Most are excellent in the basics, but not always clued in when subtle interactions cause problems. If you can't solve this yourself, you might consider letting another shop look at it.

Also don't think you'll solve the problem with a stronger hanger. You won't, what'll happen is that the hanger will hold and the derailleur will bear the brunt of whatever's causing the breakage.

Since the hanger is being torn backwards it's safe to assume that the RD is catching on something, though apparantly not the spokes. Because it happens on the granny gear I'm guessing that it might be a form of long chain issue.

Set the bike back up and using the granny, take the RD up through a few cogs. Turn the pedals with a finger lightly touching the RD and feel any signs of snagging.

You can also look for potential problems. The chain should always run free for a short distance from the upper RD pulley before engaging on a cog. On some RDs and with certain chain tension situations this the free area can become very short or non-existant. You might even have a situation where the same link is simultaneously engaged on the pulley and the cog. This zero clearance arrangement can cause the Rd to be pushed back especially during a shift, or possibly when a damaged link comes through.

If I'm right check if a shorter chain might help by using two fingers to twist up a bit of chain on the lower loop and seeing if the RD pulls away from the cassette a bit. If yes, consider shortening the chain, or experimenting with the screw that controls the hang angle of the RD to bring it away from the cassette.

As I said earlier, if you can't figure it out, and your present LBS can't either consider another shop. I know lots of shops all over, so you can feel free to PM me and I might be able to refer you to someone.
 

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Discussion Starter · #19 ·
I think you might have figured it out. The teeth on the top pulley of the RD were catching on the teeth of the cluster. I think I fixed it by shortening the chain. Now I just need to wait. For better weather so I can go for a ride.
 

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Very well written FB!

I've been fascinated in this topic since snapping a dérailleur hanger a few months ago. But in that instance a) I was guilty of changing down under load, and b) the chain somehow got jammed between the spokes and the cassette (despite having been professionally adjusted by an LBS). As well as snapping the hanger, that little episode also wrote-off a near-new SRAM chain, an X-9 dérailleur (long-cage), and damaged a handful of spokes! That disaster was both frustrating and expensive!

Subsequently, I've sworn right off long-cage dérailleurs (I downgraded to an X-7 medium-cage instead), and now I'm ultra diligent about never cross-chaining, and never changing-down under load.

A suggestion to the OP: don't automatically believe the claims that a long-cage dérailleurs are better, more reliable, solve world-hunger, or whatever else. Do some research, and take a look at what pro XC riders are riding, then make your own decision. For me, I'm convinced a medium-cage unit works better, but only because I'm now paranoid about never cross-chaining.
 
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