Changing the cage on the SRAM eTAP rear derailleru

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ComradeSpear
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Changing the cage on the SRAM eTAP rear derailleru

Postby ComradeSpear » Sun Aug 27, 2017 8:36 pm

Got a Ritchey Breakaway fitted with SRAM eTap and toying with the idea of putting an 11-32 cassette; however, the rear derailleur doesn't have a long cage.

A new WiFli RD is availabe but wondering if there's a more economical & legit hack to fit the bigger cassette :) .... Has anyone changed the cage or the SRAM eTap RD's or have any brilliant ideas?

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Uncle Just
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Re: Changing the cage on the SRAM eTAP rear derailleru

Postby Uncle Just » Sun Aug 27, 2017 9:01 pm

Would a wolftooth road link work.....?
https://www.wolftoothcomponents.com/products/roadlink

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Duck!
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Re: Changing the cage on the SRAM eTAP rear derailleru

Postby Duck! » Sun Aug 27, 2017 9:42 pm

You will need the WiFli derailleur to fit a 32, as in SRAM's case the upper body is longer than the normal model to fit the bigger cassette.
I had a thought, but it got run over as it crossed my mind.

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ComradeSpear
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Re: Changing the cage on the SRAM eTAP rear derailleru

Postby ComradeSpear » Mon Aug 28, 2017 12:35 pm

Uncle Just wrote:Would a wolftooth road link work.....?
https://www.wolftoothcomponents.com/products/roadlink


I've got one of those but I've been advised by my LBS that it won't work. I might contact Wolf Tooth direct and see if they can provide further details.

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ComradeSpear
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Re: Changing the cage on the SRAM eTAP rear derailleru

Postby ComradeSpear » Mon Aug 28, 2017 12:40 pm

Duck! wrote:You will need the WiFli derailleur to fit a 32, as in SRAM's case the upper body is longer than the normal model to fit the bigger cassette.


Yeah, that's what I've read too. Is it possible to fit a Red22 long cage as an option like this?

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Duck!
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Re: Changing the cage on the SRAM eTAP rear derailleru

Postby Duck! » Mon Aug 28, 2017 1:50 pm

Not really. The cage only determines the available chain length. Sprocket clearance comes from the upper body geometry. SRAM's standard derailleurs have a quite compact main body which limits them to 28T max. As I said above, WiFli derailleurs have a longer main body which lowers the upper jockey wheel to fit under larger sprockets.

By contrast, not relevant in this case but of interest to others, Shimano use the same upper body for both cage lengths, so if a model is compatible with a 32T, the short will happily do it, but chainring difference plus chainstay length dictate if the chain length is enough.
I had a thought, but it got run over as it crossed my mind.

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Duck!
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Re: Changing the cage on the SRAM eTAP rear derailleru

Postby Duck! » Wed Aug 30, 2017 9:58 pm

UPDATE:

Actually just finished doing a SRAM tech course, and this question was raised. It is NOT possible to change cages (as in changing length; they can be replaced like-for-like in the event of damage) on SRAM derailleurs. As mentioned above, the upper body also differs between versions, but additionally the short cage has a non-offset top pulley, while the longer cage has an offset pulley. This difference affects the mounting of the cage to the body, rendering it impossible to bodge a hybrid derailleur.
I had a thought, but it got run over as it crossed my mind.

usernameforme
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Re: Changing the cage on the SRAM eTAP rear derailleru

Postby usernameforme » Thu Aug 31, 2017 8:27 am

This is definetly a bodge, but a friend of mine runs a wolf-link on a short cage ultegra 6770 rear mech, and it clears a 36. The biggest problem is that the chain is 'too long' for the short cage mech.

I was thinking with your red rear mech, perhaps you can change the cage to a long cage (to take up the extra chain slack) and then use a wolf-link to get the clearance you need.

P.S. you should probably listen to Duck since he's done a course.

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ComradeSpear
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Re: Changing the cage on the SRAM eTAP rear derailleru

Postby ComradeSpear » Thu Aug 31, 2017 7:49 pm

My LBS advised the same as Duck!

I'll buy the long cage WiFli RD and sell the short one... Bloody expensive though :roll: !

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