Replaceable Rear Derailleur Hanger

[MontyBiker]

I have a carbon frame with an aluminum replaceable rear derailleur hanger. The hanger seems to easily get out of alignment because of the softer aluminum -- especially if I cross chain alot. Yep, I am really bad about using my 53 chainring with my last 3 cogs!

Anyway, use to have a steel and all aluminum frames, so hadn't had this problem before. Anyone else experience this issue? What do you do to keep from always needed to realign your rear derailleur hanger?!

Stop using bad gear combinations LOL

[DebW]

Just noticed a new Shimano rear derailleur, the Saint, with a new mounting system that supposedly attaches to the hub axle. Maybe it's a response to your problem.

[ridebikeme]

Ummmm... my suggestion is also to stop crosschaining... if you find that that is the gear combination that you are most comfortable with than perhaps you should change your cassette to accomodate that choice...or perhaps even change to a compact crank.

You didn't mention whether your bike is a double or triple, however the Saint hub would be quite a bit of work for a shop to set up. First, it's a mountain bike hub that is spaced differently than a road bike(mtn bike spacing is 135 and road is 130) . A shop could change this to accomodate your bike, but it's also a long cage derailleur...is that what you have on your bike now? If not, then the shifting will be quite a bit slower with more chain slap when you shift. The long cage derailleurs are setup for cassettes that are 27 tooth and up.. is yours in that range?

You mentioned that your derailleur hanger keeps bending ... have you replaced it each time that has happened? You can generally bend these back, but obviously they are not as strong as they once were...

Good luck with this!!

[Kitsune06]

oh, but the Saint is so hot...

[Batbike]

Ummmm... my suggestion is also to stop crosschaining... or perhaps even change to a compact crank.

You didn't mention whether your bike is a double or triple, however the Saint hub would be quite a bit of work for a shop to set up. The long cage derailleurs are setup for cassettes that are 27 tooth and up.. is yours in that range?

You mentioned that your derailleur hanger keeps bending ... have you replaced it each time that has happened? You can generally bend these back, but obviously they are not as strong as they once were...

Good luck with this!!

To address above important points:

YES! I need to stop crosschaining -- however, VERY surprised that a 53-21 or 53-23 combo would cause this problem (thought it would happen only at extreme level of 53-26). I don't crosschain at extreme level, but at the other gears. I have been working on dropping to lower 39-15 or 39-16 to compensate. I have a traditional double 53/39 crank with a 13-26 cassette. I may eventually change to compact 50/34 and 12-25 cassette. I would not use the Saint hub.

As for derailleur hanger bending, yes, I have had LBS realign it -- which I guess is bending it back. I am thinking about getting a speciality/welding shop to weld me a new hanger made of stronger material such as steel or ti. Not sure if this can be done, but I think it could be ...

Bottom-line, thinking the problem is with the derailleur hanger, so that is what needs to be strenghtened. After that it would be a gear combo issue and the need for a compact crank. Any one have thoughts on my thoughts?

[KnottedYet]

Mechanical engineering question:

Is the hanger on a carbon fiber bike made made of aluminum so that the aluminum will fail rather than sending the stress into the delicate carbon fiber?

Sort of a 'sacrifice the hanger to save the frame" situation?

My cheap-o aluminum frame bike has a steel hanger. (magnet sticks to it, so I assume it's steel)

[ridebikeme]

Very wise thoughts on replacing the hanger... you definitely have to be concerned with the material of the frame vs the hanger. If the hanger is stronger than the material of the frame, you could potentially damage the frame... which is a much bigger expense. I would generally NOT think about bending the hanger back unless I didn't have a choice ...if I had to order one or needed to get myself back home. Even though your LBS can bend it back very accurrately, it still is NOt the same strnegth that it once was. The other issue could be that the bike may have some sort of chain line problem... other than the obvious of cross chaining... you might have them check that as well.

The idea of the compact crank will definitely give you lower gearing, and might just fill that need!

Good luck!!

[Batbike]

Very wise thoughts on replacing the hanger... you definitely have to be concerned with the material of the frame vs the hanger. If the hanger is stronger than the material of the frame, you could potentially damage the frame... which is a much bigger expense. I would generally NOT think about bending the hanger back unless I didn't have a choice ...if I had to order one or needed to get myself back home. Even though your LBS can bend it back very accurrately, it still is NOt the same strnegth that it once was. The other issue could be that the bike may have some sort of chain line problem... other than the obvious of cross chaining... you might have them check that as well.

The idea of the compact crank will definitely give you lower gearing, and might just fill that need!

Good luck!!

Two questions based on above:
1. Are you saying it is NOT a good idea to get a new hanger in a stronger material because it would be too heavy?
2. What sort of "chain line problem" ... I don't understand what this could mean?

Thanks!

[Batbike]

Mechanical engineering question:

Is the hanger on a carbon fiber bike made made of aluminum so that the aluminum will fail rather than sending the stress into the delicate carbon fiber?

Sort of a 'sacrifice the hanger to save the frame" situation?

My cheap-o aluminum frame bike has a steel hanger. (magnet sticks to it, so I assume it's steel)

I believe that is true ... instead of having to replace the entire frame, you end-up saving frame and replacing hanger.