[six7seta]

well last night ride around on the street my second derailer snapped on me. the first time (back in May) it happened because it swung into my rear wheel. so i ditched the large chain ring for a bashguard and shortened the chain.

now the second time...

I did have a nasty crash last week, but the bike was just fine and i rode it on a jogging trail for 32 miles on tues with zero problems, and last night was riding on the street and noticed it was having a little trouble shifting and finially when i shifted it just snapped.


so wtf is going on? Lucky for me the second one i bought a more "beefy" one with a one year warrenty so I get a new one. But I hate having this happen and Im bound to trash another wheel if it breaks again. And thoughts would be great

 

[ultraNoob]

Front or Rear Derailleur... Pics?

 

[ThePriceSeliger]

Front or Rear Derailleur... Pics?

If it goes into the rear wheel, I will give you one guess which one it was.

 

[ultraNoob]

If it goes into the rear wheel, I will give you one guess which one it was.

well... he did mention chain ring and bash guard, so the front may be a possibility, can't really tell for sure cuz six7seta didn't post pics.

Pics would be a big help in this case. Especially of the actual bent derailleur while it's still on the bike. Photos of the aftermath wouldn't really be helpful, but sure would be amusing.... so if you want, add those too.

 

[PatBranch]

What der. is it?

 

[six7seta]

yes its the rear. i dont have pics. but here is a google photo of whats it broken.

 

[six7seta]

thats where it broke both times... its just werid because this time because i was just riding, no jumps or hard riding.

 

[Wumpus]

Too short a chain???

 

[six7seta]

dont think so. the day before i put down 34ish miles with no problems.

 

[PatBranch]

Bad luck?

 

[six7seta]

could be bad luck. Im at the shops around here for riding hard.

 

[PatBranch]

haha... Maybe they are all giving you lemon der.s.

 

[MtnbikeMike]

Check your hanger alignment. You could have bent it in your little mishap, and all it took was shift.

 

[six7seta]

that crossed my mind. I dont have a rack so i have to break down the bike and stuff it in the trunk.

 

[Dh_Addict44]

its probably your limit screws. if its going into your rim when its on the lowest speed drive in the screw on the derailer that says "low" or it might have "L" and that should do it

 

[DownCycles_Stef]

If it didn't swing into the rear wheel this time, it probably isn't the Low limit screw. There are a few things you'll want to check. First check both limit screws. For the lower screw shift into the low gear and turn the screw until it makes contact + 1/4-1/2 more turn. Then shift into the high gear and try manually pushing the derailleur into the low gear. If you still hear it trying to climb past that gear, bring in the screw a little more. For the High limit screw, tighten it (while in the high gear) until you hear it start to try and climb then back off 1/2-1 full turn, check for a good shift into the high gear then. If it won't shift into the high gear back off the High limit screw a little more. Next check your B-Tension screw. It's located on the backside of the derailleur next to the mounting screw. Shift into the Low/Biggest gear in the back and see how far away the upper jockey wheel is from the low gear. Shimano Derailleurs should be as close as possible to it without grinding, SRAM derailleurs should have ~4-5mm spacing. Unscrew the B-Tension screw to bring it closer, tighten it to pull it away. Shift out of and back into the low gear to check it's neutral position after adjusting it.

Finally you may want to check all your gears (front and back) for bent teeth. If you have a bent tooth, it may have caused chain suck which can overload and snap a derailleur. A firm "technical tap" with a hammer or tweak with a plier will usually sort bent teeth out. Finally also check your chain for any stiff links.

If all that checks out and you still have issues, time for a trip to your LBS.