Sram etap FD chain drops

Discuss light weight issues concerning road bikes & parts.
jeffy
Posts: 1255
Joined: Sun Oct 05, 2014 11:51 pm

by jeffy

@1415chris when you say added a Rotor shim i would automatically think you mean one of the spindle shims, but they way you mention it, it sounds like the shim is attached to the front mech ? ?

1415chris
Posts: 1085
Joined: Sat Apr 18, 2009 8:59 am
Location: Surrey UK

by 1415chris

Rotor as the brand of my crank and chain rings
Their FD shims, supplied with QXL rings
Image

felshampo
Posts: 4
Joined: Mon May 08, 2017 4:11 pm

by felshampo

1415chris wrote: setting up the correct FD angle, which has a big impact on shifting.
.


What have you found is the correct fd angle. I have mine lined up with the marks inline with the big chainring

Det55
Posts: 9
Joined: Mon Apr 09, 2018 7:28 am

by Det55

Hi, as a new participant on this platform I like to share my curent experience wirth the Etap.

I ride a new Colnage V2R with 52/36 and 11-32. After several adjustments and kms on the road I must confirm that the chain drop over the big chainring is an issue. I happens in one of 100 kms, especially when there is no torque, high rotation on the chain and when you are on the last two gears. Bringing the derailleur slightly down to the chainring would solve the issue (perhaps) but then you will not be able to ride the last 4 gears with the big chainring because the chain scratches at the inner nose of the derailleur. Reducing the gap of the end position of the derailleur will force the same. Riding smaller cogs 11-25 i.e. would also no problem because the vertical angle of the chain is not that steep. Before I tried the compact 50/34 but i have to say this option is the worst I´ve tried with the etap, chainrub while riding the chain crossed, chaindrops outside because you cannot mount the derailleur so low unless you would ride only 50-23 as a maximum crossed.
For me SRAM should limit the overshifting for some x/10mm, it is not necessary to have this full angle. The other option would be a trim function like the DI2 while riding the chain crossed, bringing the derailleur slightly outside that the chain will not touch the inner nose (chain catcher?).

If I could choose again I would go for DI2.

Regards Det

TobinHatesYou
Posts: 1212
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

I run 50/34x11-32 and do not have these issues with chain drops. The most difficult front shifts take place while in the middle of the cassette.

I used to run my FD higher as is the common suggestion for eliminating chain-rub on the “nose” you describe inside the derailleur cage while in the biggest cogs. This is actually a mistake. It is better to run the derailleur in the lowest possible vertical position while relaxing the high limit a bit. I basically add enough turns to the low limit and position the outer cage plate over the tallest tooth. I set the height to 1mm, then return the low limit to a reasonable setting. I set the high limit to 1mm or slightly larger...this eliminates the rub in 50x32 on the top of the derailleur cage.

Also when setting the yaw of the FD, you need to temporarily turn the high limit in to the point where the front guide mark lines up perfectly with the chainring.

Of course all this goes out the window when trying to use oval chainrings. I have never gotten shifting working with eTap and Q-Rings on my Emonda. It was way better on my Swiss Cross. I have yet to try the large Rotor shim meant for QXL rings, but I have tried the SRAM angled shim meant for compact rings.

1415chris
Posts: 1085
Joined: Sat Apr 18, 2009 8:59 am
Location: Surrey UK

by 1415chris

I 've been using Osymetrics (50/38) for a while and have to say that shifting between the chainrings is crispier than in QXL 52/36 case.
Again, overshifting solved with fine limit screw adjustment. I use additional derailleur wedge pushing the mech back and tilting the edge of the cage down.

Det55
Posts: 9
Joined: Mon Apr 09, 2018 7:28 am

by Det55

TobinHatesYou wrote:
Mon Apr 09, 2018 8:08 am
I run 50/34x11-32 and do not have these issues with chain drops. The most difficult front shifts take place while in the middle of the cassette.

I used to run my FD higher as is the common suggestion for eliminating chain-rub on the “nose” you describe inside the derailleur cage while in the biggest cogs. This is actually a mistake. It is better to run the derailleur in the lowest possible vertical position while relaxing the high limit a bit. I basically add enough turns to the low limit and position the outer cage plate over the tallest tooth. I set the height to 1mm, then return the low limit to a reasonable setting. I set the high limit to 1mm or slightly larger...this eliminates the rub in 50x32 on the top of the derailleur cage.

Also when setting the yaw of the FD, you need to temporarily turn the high limit in to the point where the front guide mark lines up perfectly with the chainring.

Of course all this goes out the window when trying to use oval chainrings. I have never gotten shifting working with eTap and Q-Rings on my Emonda. It was way better on my Swiss Cross. I have yet to try the large Rotor shim meant for QXL rings, but I have tried the SRAM angled shim meant for compact rings.
Interesting approach, I am not sure if I am right but it seems to me that the amount of overshifting is not influenced by the high limit screw. While over-shifting the derailleur makes a defined (over-) shift. Shortly after the over-shift it goes back to the position which is limited by the limit screw.
But "relaxing" the limit screw a bit would mean that the derailleur goes more inside and the chain will rub at the nose earlier in the biggest cogs, especially when you bring him down?! Turning the screw clockwise will reduce the clearance between the chain and the cage. Have you done this?

IchDien
Posts: 252
Joined: Mon Nov 05, 2012 12:23 am
Location: Veneto

by IchDien

A bit worrying to read...I was thinking about upgrading to eTap with a Rotor Flow and 53/39 Q ring set up but?

Det55
Posts: 9
Joined: Mon Apr 09, 2018 7:28 am

by Det55

I had an mechanical Red 22 with Rotor Q-Rings and always problems. Before I owned a DA 10-Speed with 50/34 Q-Rings and 11-27 without any concerns. If I were you I would take an Shimano Group but this is based on my personal experience. I like SRAM, use it on my mounty but on the road it isn‘t par to Shimano which I have experienced as fuzz-free. ....but this is only my experience


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TobinHatesYou
Posts: 1212
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

IchDien wrote:
Mon Apr 09, 2018 4:10 pm
A bit worrying to read...I was thinking about upgrading to eTap with a Rotor Flow and 53/39 Q ring set up but?
As someone who likes Q-Rings, but uses round rings with eTap, I cannot recommend the combination. If you must have Q-Rings, go with Shimano.

jlok
Posts: 505
Joined: Tue Jun 30, 2015 3:30 am

by jlok

I got chain drop every time I have my.bike serviced by my lbs. The mechanic just love to give the FD high limiter 1/3 turn towards the outside. With that the chain drop easily when shifting to big ring.

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yantu
Posts: 5
Joined: Wed Apr 11, 2018 11:03 am

by yantu

Just got myself an etap upgrade kit. Though not yet installed, pairing was already done. tried shifting the FD and it is functional. the only thing i noticed is that sometimes it over-shifts and move back a bit (like trim) and sometimes this movement doesn't happen (it would just shift/move 1 time and that's it).
anyone experienced the same?

TobinHatesYou
Posts: 1212
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

It always overshifts and then resets to the high limit a half second later.

yantu
Posts: 5
Joined: Wed Apr 11, 2018 11:03 am

by yantu

TobinHatesYou wrote:
Wed Apr 11, 2018 1:13 pm
It always overshifts and then resets to the high limit a half second later.
then my FD is facing some issues...by the looks of it, and based on reviews, might be selling this kit even before installation. :(

yantu
Posts: 5
Joined: Wed Apr 11, 2018 11:03 am

by yantu

yantu wrote:
Wed Apr 11, 2018 1:27 pm
TobinHatesYou wrote:
Wed Apr 11, 2018 1:13 pm
It always overshifts and then resets to the high limit a half second later.
then my FD is facing some issues...by the looks of it, and based on reviews, might be selling this kit even before installation. :(
i'm taking back what i've said...just finished installing my etap and set-up done...
1st attempt and got it on the spot! crisp FD shifting and trim is working as well. Glad no issues encountered using Q-rings...

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