How to break a rear derailleur?
- Thread starter NRSracer
- Start date
The most common in my experience is that a stick on the trail gets kicked up, insinuates itself into the cage, and pushes the cage into the rear spokes. THe turning wheel does the rest.
I saw another derailleur self-destruct when a bunch of long grass wrapped around one of the pulleys with the same effect.
J
I saw another derailleur self-destruct when a bunch of long grass wrapped around one of the pulleys with the same effect.
J
I cut a corner really tight a ripped it off the hanger. It was mush 
Well you can try to hop up on a picnic table bench and not quite make it so you land on the rear derraileur with all the 200+ lbs of bike and rider.
That is my method. My friend did the whole stick through the derraileur and stuck in the ground bending it and rendering it useless.
Oddly enough in that last situation the four prongs on my park chain tool were just the right size to fit around the bolt that holds the derraileur on his bike so we were able to take it off and ride back single speed style.
That is my method. My friend did the whole stick through the derraileur and stuck in the ground bending it and rendering it useless.
Oddly enough in that last situation the four prongs on my park chain tool were just the right size to fit around the bolt that holds the derraileur on his bike so we were able to take it off and ride back single speed style.
Ride whistler. Land a jump on A-line correcttly. Hear your derailer get sucked in your wheel. Feel the spokes snap.
werd
werd
You could also come off a little 1' dropoff and start pedalling out, only to find the body of your brand-new LX rear has snapped n half on the outer plate for no apparent reason. Then you could fork over $80 to the local parts pirates to keep riding (and get a short-cage XT that doesn't fit your gear range)...and lose a rear brake connector on the next run.
My SRAM derailleur developed the odd characteristic of getting stuck in the lowest gear...even off the bike. Move it to the inner limit, and it would just stay there. Tried lubes and solvents and everything else in between, and it was just worn out.
I've just begun building frankenderailleurs out of all my broken shimano mechs. Deore cage, xtr body, LX pulleys...whatever works.
MD
My SRAM derailleur developed the odd characteristic of getting stuck in the lowest gear...even off the bike. Move it to the inner limit, and it would just stay there. Tried lubes and solvents and everything else in between, and it was just worn out.
I've just begun building frankenderailleurs out of all my broken shimano mechs. Deore cage, xtr body, LX pulleys...whatever works.
MD
Take out those stupid set screws on the back of the derailleur. They just add weight and you don't need them if you set your shifters right!
What part don't you get? Free yourself from the shackles of conformity!
dont like weight huh?
well, i have 2 tubes and 2 tires in/on my rear wheel!
Well, you gotta get it to the point where you only have two SPOKES back there...
MikeD: be serious for me. Well, maybe it would work if you had thumbshifters and were careful but, otherwise, it's just another way to wreck a derailleur (and other stuff).
MikeD: be serious for me. Well, maybe it would work if you had thumbshifters and were careful but, otherwise, it's just another way to wreck a derailleur (and other stuff).
D
dwnwrd
Guest
so, bullits don't have replacable hangers. someone said i oughta get an alluminum bolt so it theoretically snaps before the frame bends. good plan? where do ya get one? are the stock bolts already aluminum? (specifically on XT)
Ah, gotcha now.Originally posted by EBasil
Well, you gotta get it to the point where you only have two SPOKES back there...
MikeD: be serious for me. Well, maybe it would work if you had thumbshifters and were careful but, otherwise, it's just another way to wreck a derailleur (and other stuff).
As to the Bullits, you'll need to ask your LBS for a 'breakaway bolt,' made of titanium, I think, but I could be wrong...whatever the material, it'll function as you described. It's a purpose-built item, not just a matter of finding a crappy bolt from a hardware store. Newer Bullits have an entire replacable dropout, though, which is theoretically a great solution to the derailleur hanger stiffness question (allows an overbuilt hanger and replacablility...)
MD
Lots of ways to break a rear derailleur. XTR can break if you wack it hard enough on something or have a large stick go through it or push it into the spokes. I 've busted off steel hangers with XTR and had the derailleur come out fine. With the "grilon" SRAM stuff its much easier to break a rear derailleur. Maybe hit a large blade of grass or look at a rock wrong and that derailleur will snap right off. That's a good alternative to getting an aluminum break-away bolt but it costs more, although SRAM have been very good at replacing derailleurs.
Ways I've broken rear derrs:
1) Bounce a pebble up between the two parallel arms, then shift in a way that brings those arms together. One of the arms will break.
2) Have the derr hit the spokes when you shift into the lowest gear (bad adjustment - but I had crashed earlier and didn't notice the slight derr hanger bend)
3) Tried and true stick method. Kick one up with the front wheel and have it hit the fairly large target of the rear wheel inside the lower chain path. When the stick goes through the spokles thw wheel will bring it stongly around to the derr cage and then rip the derr off in an upwards direction (or at best give it a really big twist). Only hope is to grab rear brake and lock it up before it does terrible damage (hockey goalie reflexes?) or hope the stick is flimsy and or brittle.
4) Ride in biblically horrendous mud at an old strip mine where the trail consists of crushed limestone and clay (Finger Lakes in Columbia MO, White Knuckle Classis, FYI). Eventually it is possible for gravel and clay to jam the chain where it enters the lower pulley. Then when you attempt to pedal your 50 lb mud coated bike up a hill the chain will pull the derr upwars, tearing it off and jamming it inbetween the wheel, seat stay and chainstay that you can't unjam it and have to drag your bike 2 miles out of the woods back to the start finish.
1) Bounce a pebble up between the two parallel arms, then shift in a way that brings those arms together. One of the arms will break.
2) Have the derr hit the spokes when you shift into the lowest gear (bad adjustment - but I had crashed earlier and didn't notice the slight derr hanger bend)
3) Tried and true stick method. Kick one up with the front wheel and have it hit the fairly large target of the rear wheel inside the lower chain path. When the stick goes through the spokles thw wheel will bring it stongly around to the derr cage and then rip the derr off in an upwards direction (or at best give it a really big twist). Only hope is to grab rear brake and lock it up before it does terrible damage (hockey goalie reflexes?) or hope the stick is flimsy and or brittle.
4) Ride in biblically horrendous mud at an old strip mine where the trail consists of crushed limestone and clay (Finger Lakes in Columbia MO, White Knuckle Classis, FYI). Eventually it is possible for gravel and clay to jam the chain where it enters the lower pulley. Then when you attempt to pedal your 50 lb mud coated bike up a hill the chain will pull the derr upwars, tearing it off and jamming it inbetween the wheel, seat stay and chainstay that you can't unjam it and have to drag your bike 2 miles out of the woods back to the start finish.
foreign object can get stuck in it, you can fall and bend the cage or hit it on a rock in passing, it can get caught in your spokes if you bend it or whack it just right, you can also just wear it out so it has so much play that it cant hold the chain in gear, or use it to the point that the spring wears out or breaks/disconnects.
My favorite is just breaking it with a hammer, so fun to watch the parts fly
My favorite is just breaking it with a hammer, so fun to watch the parts fly
I dont believe this statement is true...
I could be wrong, maybe Im just a crappy mechanic, but not likely.
- JB
D
dwnwrd
Guest
I'm pretty sure that was a joke.
...especially given the title of the post...
Don't MAKE me go back and delete that post out, don't make me!
