Yup... another etap front derailleur thread. Sanity check.

Discuss light weight issues concerning road bikes & parts.
RocketRacing
Posts: 563
Joined: Thu May 10, 2018 2:43 am

by RocketRacing

Hi folks,

After my first time diy setup of di2, i figured it was time to dive into my etap setup. LBS set it up originally with the wedge. After a while (two-3minths) it started disliking shifting into the big ring unless i was on the 5th or 6th smallest cog or less. I had my lbs look at it again and they tweaked the FD. Problem not solved. More reciently, it was having very mild issues shifting in the back in that 5-7th cog range also.

2015 felt f2 with braze on fd adaptor. Compact chainrings.

So like any good newb, i read the sram setup guide (crap on details), and various videos (also crap on details). I also read some threads on the topic, and found one that adressed my question.

So from my asessment, the FD was tailed out too much (wedge adjustment), and the outer edge of the fd was too far away from the biggest teeth of the large chainring. Sram and all videos seemed to say 1-2mm. Mine was 5mm. Sure... 1-2mm if i shift the deraillier to the small ring position.

Now, i read on this forum that 1-2mm is crap, and farther away is fine, if not better.

Regarding the vertical placement/fd height line... i could not get any better than having the large cog teeth just reach the bottom of the guide line. The slot in the fd plastic housing that hugs the top of the braze on bracket will just not let me lower the fd any more (a subcompact setup on my bike would be screwed... but don’t worry, i am too manly to need one). Taking a few mm off the bracket with a hacksaw would solve that problem... but before i break out good old rusty... i figured i would sanity check (i like my black anodizing).

So again, some here said that positioning the big tooth at the bottom of the vertical placement line is ideal. That is what i have, like it or not. I can’t get it any closer. And some people say that the 1-2mm distance between the fd (positioned for big ring) and the big teeth is also garbage advice, and more space is realistic.

So who is right? Is the ideal setup different between compact, semi compact, and regular chainrings? Is the internet smarter than sram? Or have a few of us just found a way to “make it work.” Do i need to break out old rusty and grind away my braze on bracket to allow my fd to go lower?

P.s. for bonus points, what is the torque of the bolt for the fd wedge? If i am lucky enough to even find an article that references it, i consider myself lucky. It is soft plastic so i just did “tight enough”.

Double bonus points. Does the wedge(s) come with the new fd? I see 2-3 options in a spare parts kit. No unboxing videos i could find even showed the wedge. Is it an add-on thing? I think I am ok with what i have, but i also think i read on this forum “to make sure you chose the appropriate shaped wedge..”

Thanks for any help
Last edited by RocketRacing on Tue May 07, 2019 4:26 am, edited 1 time in total.

by Weenie


TobinHatesYou
Posts: 3052
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

The answer to derailleur height, yaw, pitch, etc. is NOBODY REALLY KNOWS.

Setting up an eTap 11spd FD so that it never throws a chain over the big ring is pretty much a fool's errand because it's a moving target that depends on chain wear, chainring wear, thermal expansion, limit screws backing out, vibrations slowly moving the FD position, etc. Right now I have my FD sitting high, the guide line is well above the edge of the tallest tooth. I also have the tail toed-inward slightly. In addition I have my high limit so close that there is slight rub between the cage and outer plates at certain points in the pedal stroke. Even with all these little changes minimizing the effect of the FD "overshift," the chain can still get thrown, albeit rarely.

Given the size of the wedge fastener, anyone doing anything other than barely finger tight might be a moron.

RocketRacing
Posts: 563
Joined: Thu May 10, 2018 2:43 am

by RocketRacing

I love your reply as it reinforces how jaded i am on all this. It all seems a bit like black magic. But sram had to get their numbers somewhere.

I have never dropped a chain. But the fd has a hard time throwing it onto the big one from any deeper than the 6th cog on the cassette.

Regarding the wedge fastner torque... finger tight is great until it is not. I think the correct torque is “just tight enought that it will not eventually vibrate lose and move.” I think that specific numerical torque equivalent is delicately in between “so tight that the fd explodes” and so loose that the wedge falls out of place, you drop a chain, and your fd and bike explodes.”
TobinHatesYou wrote:
Tue May 07, 2019 4:21 am
The answer to derailleur height, yaw, pitch, etc. is NOBODY REALLY KNOWS.

Setting up an eTap 11spd FD so that it never throws a chain over the big ring is pretty much a fool's errand because it's a moving target that depends on chain wear, chainring wear, thermal expansion, limit screws backing out, vibrations slowly moving the FD position, etc. Right now I have my FD sitting high, the guide line is well above the edge of the tallest tooth. I also have the tail toed-inward slightly. In addition I have my high limit so close that there is slight rub between the cage and outer plates at certain points in the pedal stroke. Even with all these little changes minimizing the effect of the FD "overshift," the chain can still get thrown, albeit rarely.

Given the size of the wedge fastener, anyone doing anything other than barely finger tight might be a moron.

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wheelbuilder
Posts: 601
Joined: Wed Feb 08, 2017 2:10 am

by wheelbuilder

My experience has been that it varies wildly bike-to-bike. So many variables. Usually you have to disregard official set up parameters and use what works for your particular situation. I also believe that the front derailleur is highly susceptible to vibration, flex,etc, as I see a lot of these shift perfectly for some time, then out of the blue start rubbing/dropping chains all over the place. While mine shifts in an acceptable manner for me, I have always been plagued with slow pick up when in middle of cassette. AXS has been so much better as far as front shifting goes. I have five customers bikes out there with it right now, and not a single complaint or concern of any sort. Not the case with my 11 spd installs.

RocketRacing
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Joined: Thu May 10, 2018 2:43 am

by RocketRacing

wheelbuilder wrote:
Tue May 07, 2019 5:28 am
My experience has been that it varies wildly bike-to-bike. So many variables. Usually you have to disregard official set up parameters and use what works for your particular situation. I also believe that the front derailleur is highly susceptible to vibration, flex,etc, as I see a lot of these shift perfectly for some time, then out of the blue start rubbing/dropping chains all over the place. While mine shifts in an acceptable manner for me, I have always been plagued with slow pick up when in middle of cassette. AXS has been so much better as far as front shifting goes. I have five customers bikes out there with it right now, and not a single complaint or concern of any sort. Not the case with my 11 spd installs.
So do i understand it right that etap dislikes going from the small to big ring beyond mid casette? I ask cause i wonder if i have unreslistic expectations. Di2 lets me shift in and out of the extremes without complaint.

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wheelbuilder
Posts: 601
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by wheelbuilder

RocketRacing wrote:
Tue May 07, 2019 5:41 am
wheelbuilder wrote:
Tue May 07, 2019 5:28 am
My experience has been that it varies wildly bike-to-bike. So many variables. Usually you have to disregard official set up parameters and use what works for your particular situation. I also believe that the front derailleur is highly susceptible to vibration, flex,etc, as I see a lot of these shift perfectly for some time, then out of the blue start rubbing/dropping chains all over the place. While mine shifts in an acceptable manner for me, I have always been plagued with slow pick up when in middle of cassette. AXS has been so much better as far as front shifting goes. I have five customers bikes out there with it right now, and not a single complaint or concern of any sort. Not the case with my 11 spd installs.
So do i understand it right that etap dislikes going from the small to big ring beyond mid casette? I ask cause i wonder if i have unreslistic expectations. Di2 lets me shift in and out of the extremes without complaint.
The opposite. Mid cassette is problematic for me and others. The extremes shift snappily.

RocketRacing
Posts: 563
Joined: Thu May 10, 2018 2:43 am

by RocketRacing

Interesting. I try not to cross chain, so i have never really triad to go frombig to big. Will try post sanity check adjustment completion. It will then go to the lbs to verify/tweak in case i have missed anything.

I am ok with the fd position, now time for high and low limit adjustment, i dexing the rd... and road test

Jugi
Posts: 397
Joined: Sun Jun 24, 2018 8:10 am

by Jugi

Where have I earned all of this good Karma? 5997 km ridden from last install, which equates to roughly 200 hours. First 120-130 hours ridden on a Tacx Neo in Zwift, rest of the time outside. Using Rotor Q-rings 52/36, SRAM and KMC chains, SRAM cassettes and the FD wedge. Because of the q-rings, I have setup the FD height so that it just clears the tallest teeth of the big chainring in all situations (no matter where the chain is).

During zwifting, got two or three random chain drops to the outside. That led to a tiny adjustment of the outer limiter screw. During outside rides, no chaindrops to report.

I have been using two wheelsets which requires some adjustment to the RD's position and limiter screws, but that has no effect on the FD. I have noticed one peculiar thing about my setup - if I ever go into small-small combination front and rear, the FD's cage is unable to move the chain to the bigger chainring. If I move the chain from 11th to 10th sprocket first and then move the FD, all is well.

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

by TobinHatesYou

The middle of the cassette produces the most challenging front upshifts because the chainline leaves a huge gap between the outer cage plate and the chain. It’s less of a problem in the largest cogs because the chain naturally wants to “fall” back to the inside. In the smallest cogs, the gap between chain and FD cage is small, minimizing the chance of the chain dropping on the outside.

1415chris
Posts: 1222
Joined: Sat Apr 18, 2009 8:59 am
Location: Surrey UK

by 1415chris

I've been on Etap for over 3 years now. I used it on 2 bikes with the same crank-chainring combo, 3d+ and QXL 52/36.
Although I tried to ply with FD I couldn't fix 100% chain overshifting. I reached the point in which overshifting happened very occasionally, but was still there. It could be funny but I developed subconscious awareness when changing from small to big ring, where part of my brain was focused on the whole process checking if everything is OK....
Because QXL were, after Q-rings a continuation of my non-round chainring journey, my next step were Osymetrics. I was a bit worry at that point. I decided to use a small wedge supplied with Rotor QXL chainrings, which moved the FD slightly back and tilted the cage down, I mounted it with thinner end pointing down. After first initial setup, maybe I had to do small limit screw adjustment, as you never know whether the bike stand performance will be the same in real life on the road.
Since then, about 18 months ago, I haven't had any single overshift. What is more, which is probably down to chainrings themselves rather than the additional wedge, or maybe both, shifting is very crisp, precise and fast. QXL were not sluggish by any means, but there is noticeable difference in favour of Osymetrics (just in case someone considers whethe Osymetric and Etap combo is workable).
I also managed in the process to free up my previously occupied brain capacity, I regained a joy of riding :)

RocketRacing
Posts: 563
Joined: Thu May 10, 2018 2:43 am

by RocketRacing

So am i good to proceed with 5mm cage to big tooth clearance (vs stam advised 1-2mm)? Should i shave the top of my braze-on to make it fall to within spec?

Is it ok that the top tooth only just reaches the bottom of the verticle adjust line?
Last edited by RocketRacing on Tue May 07, 2019 10:53 pm, edited 1 time in total.

bikeboy1tr
Posts: 332
Joined: Thu Mar 21, 2013 3:19 am
Location: Southern Ontario Canada

by bikeboy1tr

I have etap on my main bike(V2R) and my wife has etap on her main bike(Movistar Dogma). I have long chainstays she has short. Like you have read on the other thread if you have long chainstay it will shift over the top, if you have short it will drop inside. For my bike I have 52/38 Rotor inner and Absolute outer. I have applied loctite to fd outer limit (max) screw to eliminate potential for movement. Fd has wedge and height set as close to big ring as possible. Fd is flush with outer ring as you look down the chainline. I decided to adjust the yaw fd the same way as I do all my fd as I am not bothered by a bit of chainrub on the big/small. I have my max screw adjusted so the chain just makes to the big without going over and avoid the centre of the cassette when shifting to big. Recently installed a new Red chain and had to adjust the max screw in a bit as it was going over with the original settings. It took some time of incremental adjustments on the max screw (turning it out) before I got the new chain to shift without going over the big but I think I have it shifting reliable again.
My wifes bike has a chain catcher installed as tight as I can get it and I had to piggyback two wedges as there was enormous clearance between fd and seat tube. For her so far no issues or at least she is not complaining so it must be good. Happy wife, happy life : )
So like THY says its a mystical thing.
"Life is like riding a bicycle. To keep your balance you must keep moving"-Albert Einstein
2018 Colnago V2R Rim Brake
2014 Norco Threshold Disc Brake
2012 Time RXRS Ulteam Rim Brake
2008 Time VXR Rim Brake
2006 Ridley Crosswind Rim Brake

ancker
Posts: 123
Joined: Sat Dec 31, 2011 9:29 pm

by ancker

I have three eTap groups. (One is 1x, so irrelevant to this discussion.)

On one bike, using Extralite (52/36) chainrings, I had it drop both inside and outside numerous times no matter setup. Switched to Praxis rings, can't make it drop no matter what. (Other than just plain terrible setup.)
The other group has been on two frames, SRAM (53/39) chainrings, never once dropped ever.

I'm very much in the camp of "varies bike to bike".

Still love my eTap. Doubtful I'll even run wires (electric or not) ever again.

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wheelsONfire
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Location: NorthEU

by wheelsONfire

No problems cross shifting using all gears (11-28) with both chainrings (50/36).
No chainrub in any combination, no chaindrop.
The 3 wedges, use the one that fits, that's why you have 3 of them.
Torque, as mentioned above and it doesn't come off.
My chainstays are 403mm.
Set up is as suggested by Sram.
Bikes:

Ax Lightness Vial EVO Race (2018.12.21)
viewtopic.php?f=10&t=156137
Paduano Racing Fidia (kind of shelved)
Open *UP* (2016.04.14)


Ex bike; Vial EVO D

bikeboy1tr
Posts: 332
Joined: Thu Mar 21, 2013 3:19 am
Location: Southern Ontario Canada

by bikeboy1tr

They should supply 4 wedges as not one of the three wedges had an offset large enough for my wifes Movistar Dogma.
"Life is like riding a bicycle. To keep your balance you must keep moving"-Albert Einstein
2018 Colnago V2R Rim Brake
2014 Norco Threshold Disc Brake
2012 Time RXRS Ulteam Rim Brake
2008 Time VXR Rim Brake
2006 Ridley Crosswind Rim Brake

by Weenie


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