SRAM YAW FD shifting "slow"/not shifting under power

Discuss light weight issues concerning road bikes & parts.
mike001100
Posts: 96
Joined: Sun Dec 04, 2016 10:26 am

by mike001100

Hi,

so a few days ago, I built up my first road bike from scratch (except BB, headset etc.) - I am running a complete SRAM RED 11 speed setup and I am having troubles adjusting the front derailleur.

All in all - I have gotten it to a state where it is rideable, but shifting of the FD, while in all gear combos with what looks to be no rubbing - does not happen effortlessly under power, i.e. putting the hammer down, I pull the lever and I hear a "hissing", if I stop pedaling and then continue, the shift has usually occurred.

Any ideas?

Also, it took me quite some time to get it to this level... can I make some minute adjustments to get it perfect, or do you recommend starting all over?

Thanks.

TobinHatesYou
Posts: 1196
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

I'm guessing the yaw of your your derailleur (top down rotation) needs to be more counter-clockwise. The tail of a yaw derailleur needs to be within a few millimeters of touching your crankarms when in the outboard position.

mike001100
Posts: 96
Joined: Sun Dec 04, 2016 10:26 am

by mike001100

Well, that's quite a paradoxical tip, as I just moved it inwards at the tail to get no rub in all gear combos...

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themidge
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Location: Auld Reekie

by themidge

When you're next out riding, watch the FD and tell us what you see. Does the chain fail to 'latch on' to the big ring (I'm assuming we're going from small to big here)? Does the derailleur struggle to lift the chain off the small ring? Also, try keeping the lever pushed all the way while the shift happens, sometimes that can help to make the shift happen.
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wingguy
Posts: 3824
Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

First things first, did you read SRAM's instructions and follow the process from the start for a yaw derailleur, or did you do what you'd normally do for any other front mech?

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LouisN
Posts: 2341
Joined: Mon Feb 19, 2007 3:44 am
Location: Canada

by LouisN

This video is handy for SRam Yaw front derailleurs:
Since I followed these instructions, no more FD shifting problems.
https://www.youtube.com/watch?v=jKzA-QVyBWo

Louis :)

TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

mike001100 wrote:
Mon May 28, 2018 10:22 pm
Well, that's quite a paradoxical tip, as I just moved it inwards at the tail to get no rub in all gear combos...
It's not paradoxical. It's how Yaw is supposed to be set-up. There are guidelines on the top of the cage for you to line up with the big ring. When you don't line things up correctly, you also end up offsetting that with wonky high and low limits. By moving the tail inward, your chain gets pushed onto the big by a smaller area on the inner cage plate during upshifts...that's why the ramps are slow to pick up the chain.

mike001100
Posts: 96
Joined: Sun Dec 04, 2016 10:26 am

by mike001100

Thank you all,

yes, I did see the videos and set up according to them - both the SRAM one, as well as the GCN one. Neither video got it perfect for me... so after lots of tweaking, I got it to the state that it's in now.

Regarding lining up the cage - yes, I did line up the marks, however, looking at the derailleur marks and the chainring, the front mark (on the top of the cage) seems to be slanted in relation to the tail mark, i.e. they do not line up in a straight line. I have gotten them as straight as possible, but, considering what is written above, what is better: to have the tail slightly inward of the big ring, or slightly outward of the big ring? (I'm talking like 0.2mm offset)

In terms of limiter screws, yes, I think it is wonky right now - as low limit screw is all the way out (i.e. if I loosen it more, nothing happens).

So, all in all, what do I do - restart the whole procedure? Or just adjust the angle of the cage gently?

Thank you.

TobinHatesYou
Posts: 1196
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

The cage itself is a solid structure. Unless there was a manufacturing defect, the guide lines cannot be slanted relative to each other. Because you perceive one of the guide lines to be correctly placed, but not the other, that means both are actually out of alignment. You are likely not looking at the chainring and guidelines at a perfectly top down angle. In addition this necessarily means your high limit is set incorrectly. Because you have rotated the tail inward, in order to bring the guide line closer to plane of the big ring, you must have pulled the high limit outward.

By rotating your tail inward, the back 2/3rds of the cage are too far inward. This means when you try to upshift the chain makes contact with the cage inner plate closer to the front. Because the shift can now in a more forward position on the derailleur, that means the chain is being picked up by the shifting pins later and grinding against the big ring more often.

Please be aware that the tail of a Yaw derailleur does not move the same distance as the front. The correct yaw angle is crucial. Stop ignoring the official instructions and set your derailleur up correctly. Aka force an upshift with the low-limit screw and make sure there is no rubbing in your big ring and smallest cog with the outer plate. Set your high limit temporarily by screwing it counter-clockwise until the bolt makes contact with the stop. Now rotate the derailleur cage so the big ring lines up with the guides. Pull the cable tight and bolt it down. Relax the lower limit and then shift to your easiest gear combo. Set an appropriate lower limit. Shift into your hardest gear combo and double-check the high limit. If you need to redo cable tension, shift back into the small ring to make it easier.

mike001100
Posts: 96
Joined: Sun Dec 04, 2016 10:26 am

by mike001100

Thanks again everyone... I took the bike to a LBS and had the FD and RD adjusted.

Now, I'm not sure how expert these guys are (they sell new bikes and are Wilier, Giant, GT dealers). I explained it was not shifting right, the sales guy put it on the stand and took like 5 minutes to adjust everything. He did not seem too concerned about FD alignment.

The bike shifted fine, but would drop the chain on the little ring. So, I adjusted the low limit screw and got some grinding... I say "shifted", since the bike fell today (I propped it up to take a picture and a gust of wind knocked it over... just my luck), and the RD hanger was bent.

I took the bike to another LBS (Cervelo, Cannondale, Specialized etc dealer) to get the hanger straightened. While the bike was there, the mechanic also adjusted the derailleurs (I didn't see it in person) claiming "it shifts well". I took it home and voila - it does shift well... but after 3 or 4 up and downshifts, it drops the chain going from big to small...

So, to fix this, is the ONLY thing I touch the low limit screw? Or could it be something else, such as derailleur angle, cable tension, etc, etc.???

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Kimmoth
Posts: 39
Joined: Wed May 30, 2018 11:33 am
Location: Melbourne, Oz
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by Kimmoth

If it's a Yaw FD, doesn't that mean there's a chain catcher?

TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Man these LBS mechanics suck.

mike001100
Posts: 96
Joined: Sun Dec 04, 2016 10:26 am

by mike001100

There is a chain catcher, but I figured that was insurance, not a function...

And yes, so far I have not been impressed by ANY LBS mechanic... from too large tires (which they claimed was brake rub and it was frame rub...), improperly adjusted Dura FD (which I got right myself), to fitment off vs Retul etc...

But, back to my question - so do I just adjust the low limit? Or, is there more to it?

alcatraz
Posts: 920
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Just do it yourself. Follow the manual.

This no rub in any gears rule you have seems strange to me. Do you want good shifting or no rub? The manual is clear about the angle of the fd. There are two lines on the cage that when over the big ring should all line up. If not then rotate it properly. Take care so it doesn't touch the crank arm. It does come awfully close.

No rub in small/small is useless. Don't mind that.

At the click just set the cable tension so that the fd just barely doesn't touch the chain in the heaviest gear (make sure you get this right, test it several times and have the limit screws somewhat loosened). Then proceed to set the limit screws. When you do an upshift you should push the lever until you hit the limit (past the click). The limit should be set so that it makes the shift barely when hitting the limit (not the click). Then you have a proper safe margin against dropping the chain over the big chainring. If you afterwards find shifting to be slow or you drop chains you don't mess with the cable tension. Only limit screws.

If you move the fd mounting position you have to recheck everything.

kgibbo1868
Posts: 106
Joined: Thu Jun 21, 2012 6:36 pm

by kgibbo1868

Also, consider your cable / cable routing. If the shifting feels slow I would have a good look as this can really make a big difference.
Pain is my friend!

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