eTap Front Derailleur Setup - Guidance Requested

[frank_h]

Quick eTap question for anyone out there in the know.

Just setup eTap last night and have everything dialed in perfectly except the FD.

I followed the instructions and have the lines aligned to the chainring, the height appropriately set, the limit screws dialed in. Shifting to the small chainring is butter smooth. However, regardless of position on the cassette, I can't seem to get enough throw to get the chain to catch and fully engage with the large chainring. It tries but can't seem to make it to the top of the rotation (12 o'clock) and this remains caught between the two until I shift back down on the FD.

Normally, I'd recheck the limit screws (done), and then add a little tension to the cable.

However, with no cable, what should I do with FD to tune in the shifting to the big ring? I started over with installation of the FD and ran into the same issue again. I could continue to dial in on the alignment marks and height, but I think I'm pretty well within the error.

Thanks in advance for the assist!

[SoCalSteve]

Stupid question ( and I'm sure you didn't do this ) but... did you start the initial set up ( lining up the lines on the derailleur to the line on the chainring ) in the wrong position?

I can tell you that once you have it pretty much dialed in, the tolerances are very narrow. ( easy to throw chain ) . Takes a bit of finessing to get it just right. But once it is, it's perfect from then on.

[frank_h]

Originally Posted by SoCalSteve

Stupid question ( and I'm sure you didn't do this ) but... did you start the initial set up ( lining up the lines on the derailleur to the line on the chainring ) in the wrong position?

I can tell you that once you have it pretty much dialed in, the tolerances are very narrow. ( easy to throw chain ) . Takes a bit of finessing to get it just right. But once it is, it's perfect from then on.

I am pretty sure I was in the right position for setup.

- Small cog on cassette, most outboard position on FD actuation (big ring).
- Set height for 1-2mm gap between ring teeth and button of cage.
- Made sure the tallest tooth was passing through the visible line when looking at the FD perpendicular to drive train path.
- Look down on it and make sure the the chain rings are aligned front and back with the markings.
- Tighten down and set the limits.

Maybe I'm just not getting the front rear alignment perfect enough. I did have some trouble the first time with tightening to the braze-on and having it shift the alignment a bit. But I was pretty certain I had nailed it the second time even after tightening.

I can check this again tonight as a first troubleshooting step.

Thank you!

EDIT I should note that occasionally it does make it up there and runs smooth, so maybe my alignment is off just enough.

[chiasticon]

Originally Posted by frank_h

- Look down on it and make sure the the chain rings are aligned front and back with the markings. .

admittedly, I've not set up eTap. but it is a yaw FD after all, so I'm guessing the overall process is similar. in this step, you want the line on the top of the FD to line up with the big chainring. after that's all good, you back off the inner limit screw (you had tightened it in to get to the big chainring after all) until it's back into the little ring and then set up as normal.

have you set up a yaw FD before? they're a little different, and finicky, but not overly difficult once you do it once or twice. one other thing I do is that once the chain is on and I wanna be 100% sure that the rotation of the cage is correct, I'll put it in little/little and make sure there's no rubbing. it should be just a hair away from rubbing, but not rub. then verify same for big/big. if you're getting rubbing there but can change rings OK, your rotation is off a bit. (this occurs more when using a band clamp adapter though.) and if you change this, make sure you then adjust limits again.

[lhuerta]

...just to state th obvious...when adjusting the high limit the der must be in high position, and more importantly, remember that the high limit screw is reverse threaded

[frank_h]

Originally Posted by chiasticon

admittedly, I've not set up eTap. but it is a yaw FD after all, so I'm guessing the overall process is similar. in this step, you want the line on the top of the FD to line up with the big chainring. after that's all good, you back off the inner limit screw (you had tightened it in to get to the big chainring after all) until it's back into the little ring and then set up as normal.

have you set up a yaw FD before? they're a little different, and finicky, but not overly difficult once you do it once or twice. one other thing I do is that once the chain is on and I wanna be 100% sure that the rotation of the cage is correct, I'll put it in little/little and make sure there's no rubbing. it should be just a hair away from rubbing, but not rub. then verify same for big/big. if you're getting rubbing there but can change rings OK, your rotation is off a bit. (this occurs more when using a band clamp adapter though.) and if you change this, make sure you then adjust limits again.

Originally Posted by lhuerta

...just to state th obvious...when adjusting the high limit the der must be in high position, and more importantly, remember that the high limit screw is reverse threaded

Right, this is indeed how I proceeded.

As an exercise, if I allow too much space between the cage and the big chain ring when adjusting the High Limit, besides the risk of throwing the chain over the big ring when shifting from the little, would this make it easier to engage the big ring? (And conversely, besides rub when in the ring, too little space meaning I wouldn't get a successful push up into the big ring) Just trying to figure out how these adjustments can remedy the probably when there is no cable tension factor.

[SoCalSteve]

Watch this video: https://m.youtube.com/watch?v=AQc8wGnF-Tk

And pay VERY close attention to the way he adjusts the front derailleur. I mentioned this before, the tolerances are very tight ( unlike Shimano ). I learned this the hard way and threw the chain a few times before I realized how close things need to be.

After that, golden. Nary an issue after a few thousand miles.

Good luck!

[Theclintc]

Did you put the shim between the derailleur and the frame? Missing it could allow enough flex to hamper proper shifting.

[frank_h]

Thanks all!

Followed some advice posted by Skunkworks in another forum.

This advice was the key. I took the high limit a lot further out, until it threw, then backed it in 1/4 to 1/2 turn until it didn't seem to throw any longer. I'm still dialing it in as I was a bit paranoid about throwing it over. But I'm at least right in that sweet spot zone now and know what I need to do for micro-adjustments.

As to other questions, height was solid, I did have the wedge in, and no, this was my first YAW.

[SoCalSteve]

Originally Posted by frank_h

Thanks all!

Followed some advice posted by Skunkworks in another forum.

This advice was the key. I took the high limit a lot further out, until it threw, then backed it in 1/4 to 1/2 turn until it didn't seem to throw any longer. I'm still dialing it in as I was a bit paranoid about throwing it over. But I'm at least right in that sweet spot zone now and know what I need to do for micro-adjustments.

As to other questions, height was solid, I did have the wedge in, and no, this was my first YAW.

Take tools with you on your first ride. What works while in a stand may not work on the road. Go through all the gears and shift the front in each one. Around the middle of the cogset seems to be the most finicky.

[frank_h]

Originally Posted by SoCalSteve

Take tools with you on your first ride. What works while in a stand may not work on the road. Go through all the gears and shift the front in each one. Around the middle of the cogset seems to be the most finicky.

It's interesting you mention this. I just hopped back on after doing some things. (I have been tweaking with the bike on the trainer so I can pedal through my testing)
Around the middle, I sometimes am still throwing over the top. It's such a small window. I've been getting really good at the back pedal re-engage method, though.

[SoCalSteve]

Originally Posted by frank_h

It's interesting you mention this. I just hopped back on after doing some things. (I have been tweaking with the bike on the trainer so I can pedal through my testing)
Around the middle, I sometimes am still throwing over the top. It's such a small window. I've been getting really good at the back pedal re-engage method, though.

Personal experience ^^^

[frank_h]

So I checked tailing the rear out a bit. This made me realize that one issue was that the front of the derailleur as a bit high - the marking for chain ring height clearance had about a mm gap between the bottom of the mark and the top of the tallest tooth. If I set this back down, it was impossible to tighten and keep the rear high enough to not hit the rear facing teeth when shifting down into the little ring. So I'm wondering if my braze-on mount needs a slight bend (bottom back a bit) to allow for a more level placement when tightened down. I have it now in a position of best compromise and about a hair width between cage and teeth when shifted into little ring.

I have the chain off soaking to apply some Squirt, so I'll try some shifting and see if this has helped.

[oldpotatoe]

Originally Posted by frank_h

So I checked tailing the rear out a bit. This made me realize that one issue was that the front of the derailleur as a bit high - the marking for chain ring height clearance had about a mm gap between the bottom of the mark and the top of the tallest tooth. If I set this back down, it was impossible to tighten and keep the rear high enough to not hit the rear facing teeth when shifting down into the little ring. So I'm wondering if my braze-on mount needs a slight bend (bottom back a bit) to allow for a more level placement when tightened down. I have it now in a position of best compromise and about a hair width between cage and teeth when shifted into little ring.

I have the chain off soaking to apply some Squirt, so I'll try some shifting and see if this has helped.

sram makes a doohicky that will adjust tilt of front der. Sounds like a slack seat tube angle. I've bent more than a few front der tabs..have only broken one

[frank_h]

Originally Posted by oldpotatoe

sram makes a doohicky that will adjust tilt of front der. Sounds like a slack seat tube angle. I've bent more than a few front der tabs..have only broken one

Perfect. I'll see if I can get one of the "doohickies" before I take to bending. Thank you!