snapped off my derailleur!

[HaydenWilson]

So this evening i snapped off the derailleur on my Giant brass. Again. I was not even taking a particulaly Big Drop! the first time i did it i did it doing a bunny hop! has anyone else had this problem and does anyone know how to beef up the mounting bracked on this damn thing so that this stops happening? I cant beleive that giant could place such a weak component on a bike that is designed to be abused doing street and dirt jumping? why use a stock component which breaks and results in deraileurs intimately involved in your bicycles spokes when they could have easily adjusted the dropout on the frame to accomodate a beefy mounting bracket? AAAAARGH makes me angry. any advice as to how to prevent this would be greatly appreciated. short of not jumping my dirt jump bike that is.

[The_Break]

So this evening i snapped off the derailleur on my Giant brass. Again. I was not even taking a particulaly Big Drop! the first time i did it i did it doing a bunny hop! has anyone else had this problem and does anyone know how to beef up the mounting bracked on this damn thing so that this stops happening? I cant beleive that giant could place such a weak component on a bike that is designed to be abused doing street and dirt jumping? why use a stock component which breaks and results in deraileurs intimately involved in your bicycles spokes when they could have easily adjusted the dropout on the frame to accomodate a beefy mounting bracket? AAAAARGH makes me angry. any advice as to how to prevent this would be greatly appreciated. short of not jumping my dirt jump bike that is.

 

Jonquil

 

Can you send me a photo of the ystem at the rear? I would like to have a look at it. Do a loto of design work so would be interested to see if I could come up with a solution.

[Tuxstir]

Those hangers are made weak for a Reason. If they didn't break you would end up breaking you derailer or worse your frame. I have made one's before out of stainless steel. But only as a back up. Would not recommend using something like that for extended periods

[DJR]

As already said, the hanger is supposed to break first so that your derailleur, which is much more expensive to replace, will be saved (hopefully).

 

If it happened twice when jumping, without crasing or getting caught on a log or something like that, you have to find out exactly why and then fix the problem rather than just making the hanger stronger. Otherwise your derailleur itself will be the victim next time.

 

My suspicion is that your derailleur got caught in the spokes when landing, and then got torn off. Was the derailleur mounting and hanger tight? Was the hanger bent inwards? Was it too close to the spokes? Was the wheel too flexible and deformed on landing, catching the derailleur? Spoke tension? Landing skew, sideways can do that. Was the wheel tight in the drop outs? Ouick release tight? Through-axle tight? Or could the wheel move on landing hard, sideways?

 

Hope this get you thinking like Sherlock Holmes! Find the culprit!

[The_Break]

Those hangers are made weak for a Reason. If they didn't break you would end up breaking you derailer or worse your frame. I have made one's before out of stainless steel. But only as a back up. Would not recommend using something like that for extended periods

 

Agreed, but I am assuming he has set his stops correctly and all is set up as it should be. He didnt change gears and a derailler should drop vertically in a jump so there should be no reason for it to get caught in the spokes in a normal situation. Besides, if he is jumping then he would most probably not be in his lightest gear.

[Manx18]

Specialized makes a "Derailleur Guard", which should stiffen up the derailleur.

 

http://www.specialized.com/us/en/bc/SBCEqProduct.jsp?spid=58190

[sputnik-f1]

It is a bit strange for it to break like that. Usually the cause is a side impact. I appreciate the fact that the hanger is supposed to bend in stead of the dropout/frame, but the hangers are ridiculously expensive for such a small piece of alu!

[Whiskers_81]

I would take the mounting bracket to an engineering firm. And get them to make it of a stronger material. I think will be expensive

[HaydenWilson]

Thanks for the Reply Guys! I will forward a picture as soon as i get the bike back. I was in my heaviest gear and landed pretty straight. it did get snarled in my spokes which did cause it to snap off. so i guess thats good cos it meant my spokes and derailleur did not break. but why it wound up doing that i am not sure. the guys at mikes bikes are super perplexed and have a suspicion that it might be the spring on my derailleur which was not tight enough to prevent the chain from slackening on impact, resulting in the arm of the derailleur bending and getting snarled in the spokes. As far as i know i had everything set up tightly and correctly for some serious jumping.

 

@ The_Break thanks for the offer mate! If this latest attempt at a fix by sorting out chain tension does not work then I will forward you a piccie and we can try and come up with a solution. maybe i should just cut out a wide circle out of perspex mount that between my gears and the spokes at the back and then there is no way the derailleur will impact the spokes?

[Just Keep Pedaling]

Your limit screws are possibly not correctly set if it goes into the spokes. You can also get a plastic guard that attaches to the spokes which prevent the derailler from snagging on them.

[Gravity Sux]

As already said, the hanger is supposed to break first so that your derailleur, which is much more expensive to replace, will be saved (hopefully).

 

If it happened twice when jumping, without crasing or getting caught on a log or something like that, you have to find out exactly why and then fix the problem rather than just making the hanger stronger. Otherwise your derailleur itself will be the victim next time.

 

My suspicion is that your derailleur got caught in the spokes when landing, and then got torn off. Was the derailleur mounting and hanger tight? Was the hanger bent inwards? Was it too close to the spokes? Was the wheel too flexible and deformed on landing, catching the derailleur? Spoke tension? Landing skew, sideways can do that. Was the wheel tight in the drop outs? Ouick release tight? Through-axle tight? Or could the wheel move on landing hard, sideways?

 

Hope this get you thinking like Sherlock Holmes! Find the culprit!

 

Another reason could be that the chain jumps off / gets caught up and when the crank is turned again the derailleur gets pulled off. Happened to someone on our ride on Saturday just riding on corrugated road. I try keep the chain on the middle blade on rough downhills to prevent it jumping off