DaveSSS 

You have a interesting ability to misconstrue just about anything written. I never made any such claim. Others report such problems- no one can make their bike work. So now you're postulating that STA is the problem? No one has ever mentioned that suspicion, but you. Just add that to all of the other impossible to prove theories.

FWIW, my frames all have relatively steep 74.5 degree STAs. I honestly don't care what the problem might be for others.

tomato coupe

This is truly one of the strangest responses I've ever read -- what did I misconstrue about your statement?
Where the heck did I claim the problem was due to seat tube angle? You have a serious problem with reading comprehension.

DaveSSS 

What other part of frame geometry might affect FD operation, other than STA?

chaadster

Well SRAM does note that their Wide designated AXS FD is for frames with geometry for expanded wheel clearance, like gravel bikes, where a wider spaced crankset is used.

Insofar as these claimed FD issues are even issues— which I don’t think they are; I think this largely something akin to a mass hysteria springing from the old SRAM Yaw deraillers— it is possible that people are using the wrong FD for their frame and crankset. I have no idea how many people having “issues” aftermarket installed their Force AXS, and very few with complaints ever indicated FD model, or even the frame model, so it’s all just a hot mess of inaccuracies and incomplete information which, when considered in light of how many Force AXS FDs are out there spec’d as OE, just doesn’t add up to something credible by my reckoning.

DaveSSS 

FWIW, I used a grx wide crank with my force FD before correcting the chainline with spacing washers to a normal road chainline. It worked, but the big ring limit screw was within 1/2 turn of being maxed out. I now have 3 grx 46/30 cranks in use with the corrected chainline. Interesting that 7 cranks, 6 frames and a dozen easy FD setups isn't considered significant experience. Somehow I've fumbled through many builds without a single problem. This issue gets repeated about once per week on the sram axs owners web page on Facebook. Most complaints are from those who just got their new bike from a local shop that can't fix the problem.

chaadster

No, I’m with you, man. And call me old school, but when I see noobs like Jonob sign up to BF this month and only make posts insisting they have “significant problems” with their FD and condemning SRAM without presenting any evidence they know what they’re talking about, what kind of bike they’re dealing with, or that they even have a Force FD, all sorts of red flags pop up for me. Oh, and don’t forget the move “a bunch of my buddies have problems too and work with different shops…”. Yeah, okay, the outlandish claims aren’t sus at all; do they really think they’re the only ones who know folks with AXS?? Where I’m from, randos blathering doesn’t amount to anything serious; it’s just peanut gallery crap.

Jonob

i agree it doesn’t make sense that three different mechanics couldn’t set up my FD properly. I don’t think it’s my shifting technique I’ve been riding road bikes for 30 years and never had a problem previously. I don’t use sequential shifting. I don’t cross chain I don’t wait for the last second when I’m pushing a gear that is too much and change down the front chain ring. I never considered frame geometry that is very interesting all three riders in my group that ride sram and have problems all ride the focus izalco max. I don’t understand why it would make a difference does anyone have any thoughts? For now I think I’m just going to change to a red front chain ring and see what happens also does anyone want to give their opinion on what is good shifting technique vs bad shifting technique

Jonob

That is an unhelpful post. I came on here looking for a solution or at least some help not for someone to suggest that I don’t know what I’m talking about. I never suggested I know what I’m talking about. I bought a focus izalco max with sram force AXS D1 in 2020.

I have dropped the chain countless times.
I have never worked on my bike. Three different mechanics have and I have continued to have chain drop issues.

you gave exactly zero solutions

chaadster

That’s a lie. Here’s your first post, a reply to the question, was the chaindrop issue even a real thing:

There is no question there, no inquiry about solutions…quite the opposite: you make the claim that you’ve found “the original Force chainring”— no matter which chainring, eh?— is the problem because it’s too flexible and that “the only solution” is to replace the chainset. Your point in posting was clearly to make the issue seem real, and was in no way “seeking solutions.”

That might have been excused as a first day newbie mistake, but your response was not to take the hit, understand the situation, and make it right, it was to attack a 14 year veteran member with thousands of posts, trying to hold me accountable to be more helpful to you, a random nobody, rather than to the community. That’s more proof that you’re probably just a bad actor who came here with an axe to grind.

DaveSSS 

Overall, this thread is ridiculous because of one poster trying to derail nearly every comment while adding nothing of value.

A link to SRAM's latest video has been posted. That video is as thorough as any, but I disagree with trying to hold the FD in position while final tightening of the clamp bolt is done. If the FD rotates out of alignment, it should be set crooked to start with so the alignment becomes correct when tightening is complete. The plastic tool is really only good for setting height. The plastic tool wasn't even made when I bought my first two Force groups.

One thing I've never read of anyone trying is to simply buy another FD to see if it works differently. The cheapest rival model has markings that may be easier to align and shifts just as well. I've also never read of anyone trying a Shimano or Campy crank as a solution. That's all I've ever used and had zero problems.

The frame geometry comment went nowhere. Sram makes a wide FD for gravel bikes with a +2.5mm chainline. Road bikes don't need it. If someone suspects a frame geometry issue, they should include what the potential problem might be. Otherwise they make no contribution to this discussion.

If you're using sequential or compensating modes, turn those off. I just set a two sprocket limit for multi-shifts and use that for compensation. If you're shifting while pedaling with a high torque on a climb, let up for a second during the shift.

I've never used SRAM cranks due to their limited range. The other brands both make cranks with a 16T difference and they work. Sram says that 13T difference shifts better.

DaveSSS 

I see nothing unusual about the geometry of the Izalco max. If you zoom in on the picture, the FD looks to be set too high, but the curvature of the cage aligns with the chain ring teeth better than it does on my bikes with 74.5 degree STAs.

https://www.focus-bikes.com/int/1069...or_combo=97278

Jonob

thanks

eduskator

It works for now. Everything was within specs when I left the LBS with the bike, but I adjusted everything ''more tightly'' and it seems to have worked.

1) Low limit screw is set so that the chain is rubbing the cage just a little when on the big / small combo (it's less than 0.5mm for sure). I will leave it like that since chain is no longer dropping between the frame and the small ring. I guess I could try 1/4 or 1/8 of a turn to push the derailleur a little further towards the frame, but I am comfortable with where it currently is.
2) High limit screw is set so that the chain is almost touching the cage (also less than 0.5mm) when on the small / big combo.
3) FD height is set to the lowest possible (top of the line)
4) FD rotational angle is as parallel as possible to the big ring

My wild guess is that low limit screw was making the chain drop when shifting from big to small ring and that the derailleur height was making the chain drop when shifting from the small to the big ring.

PeteHski

That sounds very similar to my setup. No cage rub, but it is as close as possible. I also have minimum FD height. Mine has been fine like this for well over a year. I've never had a chain drop on the inside and just 3 isolated drops on the outside.

tomato coupe

Better to have the drops on the outside, even if more frequent, since you can usually just shift the chain back onto the big ring.

DaveSSS 

Here's something never mentioned. Cranks with two separate rings must be properly aligned. There's usually some mark that must be aligned with the crank arm. I have read of one person having rings attached out of alignment. It won't shift well.

Jonob

so do you think this may be why the one piece of metal for the two chain rings like the red chain ring fixes this?

DaveSSS 

One piece rings aren't likely to fix anything. You just have to be smart enough to put two rings on the crank arm properly.

Jonob

i read on another forum someone suggested that road vibration may move or loosen the upper and lower limit screws and this may result in a chain drop. They suggested using some low grade loctight or some other product to make sure the screws don’t move

does this sound possible or reasonable?

eduskator

L and H limit screw loosening up on a 3k$ groupset? Gotta love Shimano.

They will both cause chain drop or rub for sure if not adjusted properly. Can't tell if there is known instances of them loosening up though.

PeteHski

Mine haven't moved and our roads are as rough AF

chaadster

I heard its caused by Russian hackers using mini-EMP generators when meddling in USA elections. Is it possible our FDs are collateral damage?

Jonob

i heard if you spent as much time riding your bike as you do trolling people on forums you could turn pro

tankist

I used to have random chain drops (all inside) until I moved FD a tiny little bit higher (bottom of the mark).

eduskator

Update on my issue - no chain drop in the last 300kms.

Lesson learned: Don't rely on the marks' possible tolerance; adjust everything as tight as possible (FD height = cage as close as possible to the big ring, FD rotational angle angle = perfectly parallel to the big ring, low and high limit screws = adjusted to no more than 0.5mm of gap between the cage and the chain).