[pnj]

Giant STP, I got the bike a few months ago. I weigh less then 160 and I don't ride real hard. small jumps, manuals, etc.

I broke the first derailer today, while hopping a curb. I figured the few months of jumping caused the thing to weaken, went to the Giant dealer, paid 15 bucks for a new one and then did a few manuals, hopped a curb, jumped a curb cut and broke the new one. WTF?

 

[Straya]

Its because you haven't turned it into a singlespeed yet

 

[aaronrocker]

yea the real question is why do you have derailer hangers?

 

[pnj]

Uh...

cause my knees are old and I like to ride up the occasional mountain...

It shouldn't be breaking this easily, so what's up?

 

[w00dy]

Because you don't have one of these.

 

[stino]

could you elaborate on "break".. what breaks? the cage? the hanger (ie part between frame and derailler) itself? picture maybe?
or do you just mean "shifting doesn't work properly anymore" ;P

 

[pnj]

The part that bolts onto the frame, the derailer hanger. the small tiny piece of crap piece of aluminum.

The second one broke (the new one) with less then an hour of riding AND I was less then 2 feet off the ground, at the most, during that hour of riding.

 

[zebrahum]

It probably has to be be due to something you're doing.
How's the chainline?
Is the chain length sufficient?
Everything adjusted properly?
Are you pedal kicking into the problem and just manhandling it into submission?
Do you have a tendency to land your 2 ft airs on your derailleur?
Do gnomes with sledgehammers follow you?

Anyway, if you're still having problems, wheels manufacturing makes der hangers for all sorts of bikes. I can't say it'll be stronger, but it's different, and different may be progress. Also, a few companies make der hanger guards that basically reinforce the whole system. Specialized used one of their Enduro bikes before they went to the newest model.

 

[JayBear]

Chain Length ...I second that

 

[pnj]

It probably has to be be due to something you're doing.
How's the chainline?

fine, far as I can tell. I was on the middle gears in the rear, and have only one in the front.

Is the chain length sufficient?

It's stock. I'm sure it could be shorter but I don't think it's too short.

Everything adjusted properly?

When I replaced the second one, the bike seemed to freewheel/backpedal fine and the chain didn't appear to be hanging up anwhere.

Are you pedal kicking into the problem and just manhandling it into submission?

I was really just coasting along. Not even pedaling. So even if I had some odd chain alignment, (I don't think I did) why would it matter if I was coasting?

Do you have a tendency to land your 2 ft airs on your derailleur?

nope. This last air was just a small curb cut to flat. The derailleur(I don't know if I like that spelling, it looks french) hasn't hit anything, except my spokes when the hanger broke.

Do gnomes with sledgehammers follow you?

they have tried in the past. I run them over with my giant knobby tires.

 

[Bicyclist]

Could your derailleur cage be bent? That might put some extra stress on the hanger, and explain why it's a recurring problem. Just a thought.

 

[stino]

The part that bolts onto the frame, the derailer hanger. the small tiny piece of crap piece of aluminum.

hmm yeah I know this from my trials days; in my case they'd brake when missing sidehops, and although in your case there's something unknown going on what causes them to brake, here's what helped me out, maybe you could give it a try: take a rather thin plate of steel (like 1.5mm), drill holes matching your current hanger, saw that piece out while trying to match the shape, and you've got your own pretty much unbreakable hanger. if it bends, just bend it back.

 

[chuffer]

derailleur slap when landing.

 

[demo 9]

do u ride fakies-i used to 180 stairs and stuff with a derailur and id do similar problems just from weakening it

 

[pnj]

Don't do fakies. well, if I do they are very gentle. Like front wheel pivots(rock walks) to roll back. I don't 180 stairs or anything. I ride pretty mellow...

 

[slimshady]

Here are my two cents. A friend of mine passed through this same issue a couple of bikes ago. To make the story short, it was a combination of poor hager sitting into the frame (we needed to scrub down the paint from the frame at that point, leaving just the plain aluminium for the hanger to sit), and a weakened derraileur tensioner spring (the one which keeps the derraileur's tension in the point where it bolts to the frame, it was a Shimano derr). After scrubbing the paint and switching to SRAM (or a Shadow type these days on the Shimano line), the problem went away. Also, be sure the area where the hanger matches the frame isn't bent or dented. Maybe the hanger flexes when you pedal-kick.

 

[pnj]

I don't pedal kick, but I'll look into the other issues. Thanks.

 

[slimshady]

I don't pedal kick, but I'll look into the other issues. Thanks.

Sorry, I've mis-explained myself. I was talking about power-pedaling, or stepping hard in the pedals (like when you come out of a nearly-full stop with a high, heavy gear engaged). That, together with the weakened derraileur mount spring, led to an excessive leverage over the hanger, in the case of my friend.

 

[Cru Jones]

Something is definitely not setup right to cause it to keep breaking. I would check the things mentioned in this thread and keep trouble shooting to figure it out. And for what it's worth, Giant will warranty the hanger and all other parts and accessories on the bike for a year after purchase. The shop may still charge labor to swap it, though.

 

[pnj]

I purchased the bike off craigslist. it was BRAND NEW, but I didn't go through a shop...

 

[Cru Jones]

Bummer, that does void the warranty. You might want to try the Wheels Manufacturing hanger. It may be a little stronger than the stock hanger.

 

[pnj]

well, I can't really test out any theories as to why it broke without buying a new hanger and probably breaking that one as well.

because I'm broke, I'd rather spend money once. So I guess I'll be looking into going SS.

For now I'll just leave my gear cluster on and get a chain tensioner.

Does the tensioner bolt onto a hanger or just sit on the axle?

 

[Cru Jones]

The tensioner takes the place of the hanger and bolts onto the frame the same way.

The giant tensioner would cost you quite a bit more than the hanger. It may be worth it to figure out what's going on, or buy the wheels manufacturing hanger. It's a tough deal, because the hanger is designed to break at a certain point... because it's cheaper to replace the hanger than it is the derailleur or the frame. But, it certainly shouldn't be breaking as easily and as often as it has for you.

 

[WaveDude]

My vote is the hanger is snapping after the derailler snags the spokes--not the other way around. Chain tension, weak derailler spring, something along those lines allow the derailler to snag a spoke on heavy landings.

 

[pnj]

The tensioner takes the place of the hanger and bolts onto the frame the same way.

is it just the Giant tensioner that bolts to the frame?

I just bought a tensioner from the LBS and the geniouses said it bolted onto the frame. However, it doesn't, it bolts onto the hanger. I don't have a hanger that isn't broke...

the tensioner looks like this
http://www.chainreactioncycles.com/Models.aspx?ModelID=20325

Dammit, I wanted to ride this weekend!

 

[Cru Jones]

Damn, that sucks. I'm pretty sure the Giant one is the only one that will mount directly to the frame. The Giant part number for that is 27034.

 

[sixgun_sound]

Uhm, which shop did you buy that from? There are many in seattle to stay away from.

Fluidride and Revolution Cycles are really the only 2 shops worth spending money at.

 

[pnj]

uhm, Which Shop Did You Buy That From? There Are Many In Seattle To Stay Away From.

Fluidride And Revolution Cycles Are Really The Only 2 Shops Worth Spending Money At.

Ghy...

 

[sixgun_sound]

Oh... yeah GHY is a good shop. I was thinking Seattle proper. The way you wrote about the "geniuses" in the lbs, I was thinking greg's or something.

 

[pnj]

I banned myself from Gregs years ago.