Replaceable derailleur hanger alignment?

[kramnnim]

RD was sitting a bit crooked on a new-to-me frame, so I dug out the DAG-1 and tried to ease it into place...and POP, it broke.

Is there some trick to this? Some hangers more brittle than others? If the new one arrives and it's not aligned...what should I do?

:mad:

[Louis]

Might have been due to too much plastic deformation of the hanger before you got the frame.

You could check the dropouts to see how things are there. If they aren't too bad, then I'd just bend the new replacement hanger as required. If the dropouts are way out of whack, then you have a bigger problem on your hands.

[Exonerv]

I did the same thing on my Dean. There are differences in the strength of various aluminums:

6061 – Mechanical Properties

Ultimate Tensile Strength 45000 psi
Tensile Yield Strength 40000 psi
Fatigue Strength 14000 psi
Shear Strength 30000 psi
Hardness, Rockwell 40
Machinability 50%

7075 – Mechanical Properties

Ultimate Tensile Strength 83000 psi
Tensile Yield Strength 73000 psi
Fatigue Strength 23000 psi
Shear Strength 48000 psi
Hardness, Rockwell 53.5
Machinability 70%

[kramnnim]

The new one is 6061...softer, weaker. More or less brittle?

[8aaron8]

To my understanding 6061 is less brittle than its 7075 cousin, however, heavier and not quite as tough.

[Exonerv]

You know, I've always thought the same thing, but wouldn't the chart tend to indicate that 7075 has a significantly higher break point considering the Tensile Yield Strength numbers...

Engineers? Frame builders? Is 7075 worth the extra few bucks considering that hangers do break with some frequency?

[kramnnim]

Maybe I should just shim/Dremel the new one if it isn't aligned. Hate to ruin another hanger. I thought it would be okay to bend aluminum such a small amount, but it snapped like glass.

The new one is machined, though...and the old one was...forged?

[bikinchris]

Aluminum will only allow itself to be bent so many times before snapping. no matter the alloy. Your hanger may have been bent more than once before you bought the frame.

[buldogge]

6061 no like bending.

We used 3003 when we needed to bend/shape to form and weld gas tanks for the race scooters.

Not sure if 7075 would be any better…as it would be more brittle I believe…definitely "stronger" though.

-Mark in St. Louis

[lhuerta]

First the obvious...make sure your hanger is mounted flush on your frame, the mounting screws properly torqued and that there is no excess carbon/epoxy flux under the hanger. Second, make sure your wheel is inserted and clamped firmly and evenly on the dropouts. Third, make sure your dropouts are aligned. Once you have those out of the way and are ready to start aligning, be sure that you move tool very slowly and then hold in place for a few seconds at the outer limit of where you are heading, before easing off. This is especially important on cheap stamped hangers which will bend like a noodle and then simply give out and snap. With stiffer machined hangers you will need to exert a bit more force to bend and again, do so slowly and smoothly....no jerking, yanking or pulling. Finesse is important if you want to get the job done well...this is certainly not a job or the ham-fisted. Good luck, Lou

[kramnnim]

This now-broken hanger doesn't look machined. It was very stiff, and did not budge at all when I put gentle pressure on it. I increased the pressure slowly/gradually and it still would not move until it cracked suddenly.

Didn't feel like like it was weak from already being bent, but who knows. I'm just scared to try bending any of them again...

[Peter P.]

I don't think aluminum hangers are meant to be aligned, partly because of their material properties. They should merely be replaced.

[oldpotatoe]

RD was sitting a bit crooked on a new-to-me frame, so I dug out the DAG-1 and tried to ease it into place...and POP, it broke.

Is there some trick to this? Some hangers more brittle than others? If the new one arrives and it's not aligned...what should I do?

:mad:

No, Yes, align it.

Get a wheels Manufacturing one?

[kramnnim]

New one is from Wheels, yes. Are they more bendable than the OEM?

[oldpotatoe]

New one is from Wheels, yes. Are they more bendable than the OEM?

Sold a bunch of Wheels ones and they come straight and can be bent if bent while riding but like mentioned, aluminum doesn't like to be bent and YES, check the frame where the der hanger lives.

[kramnnim]

Dropout looks fine, nice thick layer of glossy paint on top of...carbon, I guess? Unless it's an alloy dropout bonded seamlessly to the stays.

[lhuerta]

I don't think aluminum hangers are meant to be aligned, partly because of their material properties. They should merely be replaced.


Nope....all replaceable hangers are made of aluminum and ALL hangers must be aligned upon installation to frame. There is no such thing as an install of new hanger without engaging in process of aligning to dropout...i.e. Hanger must be aligned to match the angle of each unique dropout on which it is installed.

[Mark McM]

I did the same thing on my Dean. There are differences in the strength of various aluminums:

6061 – Mechanical Properties

Ultimate Tensile Strength 45000 psi
Tensile Yield Strength 40000 psi
Fatigue Strength 14000 psi
Shear Strength 30000 psi
Hardness, Rockwell 40
Machinability 50%

7075 – Mechanical Properties

Ultimate Tensile Strength 83000 psi
Tensile Yield Strength 73000 psi
Fatigue Strength 23000 psi
Shear Strength 48000 psi
Hardness, Rockwell 53.5
Machinability 70%

I'm pretty sure you mean 7005 aluminum. 7075 really isn't weldable.

[Exonerv]

According to the website...it's 7075. http://www.paragonmachineworks.com/cgi-bin/commerce.cgi?search=action&category=0005

[Mark McM]

According to the website...it's 7075. http://www.paragonmachineworks.com/cgi-bin/commerce.cgi?search=action&category=0005

Oops! I misread - thought we were talking about the (welded on) frame dropout. A machined bolt-on hanger is actually a good use of 7075 aluminum (better for this application than 6061).

[Peter P.]

Nope....all replaceable hangers are made of aluminum and ALL hangers must be aligned upon installation to frame. There is no such thing as an install of new hanger without engaging in process of aligning to dropout...i.e. Hanger must be aligned to match the angle of each unique dropout on which it is installed.

You mean to tell me that most dropouts today aren't straight to begin with?

It stands to reason that when the frame and its dropout leaves the factory, that the dropout should be straight and bolting on a hanger should require no alignment. So you're also saying manufacturers can't hold tight enough tolerances on the bolt on hangers to mate with a presumably straight dropout?

Are all those glued in or molded in dropouts really that bad?

And it gets worse-you're going to align cheesy soft aluminum hangers (vs. steel) and count on long term reliability?

[oldguy00]

You mean to tell me that most dropouts today aren't straight to begin with?

It stands to reason that when the frame and its dropout leaves the factory, that the dropout should be straight and bolting on a hanger should require no alignment. So you're also saying manufacturers can't hold tight enough tolerances on the bolt on hangers to mate with a presumably straight dropout?

Are all those glued in or molded in dropouts really that bad?

And it gets worse-you're going to align cheesy soft aluminum hangers (vs. steel) and count on long term reliability?

I get your point, but the fact is, it doesn't take much of a variance in the angle for it to be off.
I have a WM brand hanger on my Cervelo S3 and was able to align it no prob.

[PacNW2Ford]

To my understanding 6061 is less brittle than its 7075 cousin, however, heavier and not quite as tough.

7075 is very slightly denser than 6061

[lhuerta]

You mean to tell me that most dropouts today aren't straight to begin with?

It stands to reason that when the frame and its dropout leaves the factory, that the dropout should be straight and bolting on a hanger should require no alignment. So you're also saying manufacturers can't hold tight enough tolerances on the bolt on hangers to mate with a presumably straight dropout?

Are all those glued in or molded in dropouts really that bad?

And it gets worse-you're going to align cheesy soft aluminum hangers (vs. steel) and count on long term reliability?

Yes, precisely. Remember that you are attaching your rear der to the end of the hanger which is positioned about 2-2.5 cm from ur actual dropout where hanger is attached, so even the slightest misalignment in ur dropout will be translated into a few mm or more of unparallel-ness, resulting in poor shifting. Also, remember that the reason hangers are made of aluminum is because the hanger is designed to break/bend in case of an impact/crash thus saving ur frame from damage.lou

PS-I am in NYC too...if u want a quick primer on how to finesse the alignment of a new hanger, bring ur hog uptown and I'll show you

[oldpotatoe]

You mean to tell me that most dropouts today aren't straight to begin with?

It stands to reason that when the frame and its dropout leaves the factory, that the dropout should be straight and bolting on a hanger should require no alignment. So you're also saying manufacturers can't hold tight enough tolerances on the bolt on hangers to mate with a presumably straight dropout?

Are all those glued in or molded in dropouts really that bad?

And it gets worse-you're going to align cheesy soft aluminum hangers (vs. steel) and count on long term reliability?

AND BB tolerances. I think some of the 'quality' of 'some' carbon bikes is really pretty poor sometimes. Being in the trenches, you get to see some really 'interesting' stuff.