SRAM AXS Front Derailleur Setup issues.....

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tomato
Posts: 729
Joined: Mon Jul 01, 2019 8:37 pm

by tomato

justonwo wrote:
Mon Jun 06, 2022 2:53 am
I have done all the setup myself. Installed the FD exactly according to SRAM's instructions. Used the little tool for positioning the FD when they released it. Have used the shims. Done everything precisely and exactly according to the manual. Have watched their videos. Have sat around thinking out loud with bike mechanics and making small tweaks to SRAM's recommended setup. Nothing has completely eliminated the FD drops on my three SRAM Red bikes.

For those of you that have never had problems, I'm not sure what to say. I don't doubt your experiences. However, realize that a not-insignificant fraction of us have consistent issues that are not related to user error. You shouldn't have to be a SRAM engineer to have the FD function without issues.

Given the sheer number of people that have FD problems with SRAM, it seems to me that there is some inherent design issue that causes intermittent FD drops. I have similarly followed Shimano's instructions for setup over the many, many years I've been using their groupsets and have never had an issue with chain drops. While there are several threads on this forum about FD issues with SRAM, I don't see anything analogous for Shimano. I do not believe this is a case of a huge number of people simply being incompetent in drivetrain setup. In the end, it really isn't that hard to setup derailleurs. Nor should it be if they are properly designed.
Yeah, the idea that the unusually high number of reported shifting problems is due to incompetence is ludicrous.

raggedtrousers
Posts: 416
Joined: Wed Dec 09, 2020 9:29 pm

by raggedtrousers

DaveS wrote:
Sun Jun 05, 2022 1:38 pm
One noticeable issue is many posters who can't do their own mechanical work and rely on some shop mechanic who apparently is also incompetent. I've never had anyone work on my bikes in the last 40 years. I actually watched the sram installation videos before my first axs installation so I didn't make a mistake with these unfamiliar components. I was fortunate to be using a chorus 48/32 crank with a crank arm that barely clears the FD cage. After fully tightening the clamp bolt, the arm hit the cage slightly instead of having 3mm of clearance. With cranks that have lots of clearance the crooked FD is easy to overlook. Some mechanics probably can't figure out how to measure a large gap accurately. I use drill bits and feeler gages if needed for fine measurements.
It seems an odd and unlikely explanation this, logically speaking. All those complaining (a diverse range of people), and all mechanics they've enlisted (also diverse) are, in this hypothesis, universally incompetent or careless, but the common system that all are using, is blameless. Occam's razor and all that...

Look, I don't doubt for a second that some people's AXS FDs have worked perfectly since day 1. That's great for them and I'm actually genuinely envious because on paper it's my favourite system.

But it's equally evident from threads on this forum, and plenty elsewhere, that AXS chain drops are very much a thing, and some of them are apparently impossible to resolve. Is the latter group in a majority? Absolutely not, but I'd guess it's statistically significant. Anecdata it may be, but one LBS stated they have had more issues with AXS FDs in the last 2 years than all Shimano products put together.

I suspect that the most likely explanation lies in a) FD hangers that are somehow prohibiting absolutely perfect alignment (or not maintaining said alignment) and/or b) some FDs being out of tolerance in their range, plane or consistency of motion. It would explain why some people have no problems while others have issues that appear unfixable. I'd be interested in an engineer's view of this hypothesis.

Finally, even if Dave S and co are correct, and that many individuals, including those apparently able to make a living from fixing bikes, do simply lack the skill to fit the FD correctly, that in itself is still a design problem. This is a bicycle derailleur ... which apparently (and quite literally) requires greater levels of accuracy in installation than a pacemaker.

by Weenie


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gycc
Posts: 7
Joined: Tue May 10, 2022 7:15 pm

by gycc

Hi All,
I know this is an old thread...I am new to sram AXS and I am curious if anyone can get a "perfect" FD setup?
I mean, keep FD in the outer location, and make chain rub free from FD when RD is in both min/max sprocket?
I can't get both RD min/max to be rub free for the FD, it's always either slightly touching one side or the other...
I don't have chain drop problem though.

maxim809
Administrator
Posts: 853
Joined: Sat Feb 25, 2017 6:28 am

by maxim809

Alright everyone. This thread is killing me. So time to spill the beans.

But first, my 3 reasons why this thread is crushing my soul. Skip below the line to dodge RAGE RANT... for more rage rant.

1. Half the people on this thread are genuinely having an AWFUL experience with SRAM's FD.

When you pay this much money, you expect the customer experience to be great. Instead, the unfortunate ones are double penalized by having to spend TIME fiddling with their FD at home. Driving your bike to every LBS in town so you can meet each of the mechanics who will surely provide the panacea to your problem. Who instead will eventually pull their hairs out chasing ghosts, just like the previous mechanic. So you go online to turn for help, and instead get ridiculed for asking innocent questions while carrying battle scars.

Hate to see this. Imagine how much you could have been riding your bike instead of dealing with nonsense.

2. Although some posters are well-intentioned and definitely trying to help, some are straight up patronizing.

"You are not following instructions!" Alright bro. One should consider that by the time someone is so deep into a problem that they're making a 'cry for help' post on a bice forum that looks like it's from circa 1980, they are probably NECK DEEP into their problem. And they probably know more about this than you, who happened to be lucky enough to avoid SRAM's FD problem and never actually had to struggle with anything to truly give any meaningful advice.

Tech support without understanding root-cause is basically, "Have you tried rebooting your router?"

3. Everyone be hating on SRAM. When SRAM is the victim. Like the customers whose struggles are real.

===================

The frame manufacturers are at fault for not building their frames to specifications.

Shimano owns numerous defensive patents that prevent competing group set manufacturers from easily making a reliable front derailleur.
Campy has figured out a way that works around these patents. SRAM has specifications that clearly state what is needed by frame manufacturers to get their group sets working flawlessly. However, some brands look to SRAM's specs as "optional guidelines" rather than HARD requirements.

Often the issue is that the FD bracket's pitch is angled out of tolerance. Ideally, SRAM would have a mechanism that allows them to finely adjust the FD's pitch after mounting. But they can't. SRAM can only provide specs to every frame brand, and cross their fingers the specs are followed. But a groupset company with 15% marketshare doesn't have the leverage nor enforcement powers to police every bike brand. Let alone inspect every frame that's popping out of every factory in the world to ensure no crooked frames reach customer hands.

If the frame's FD mounting bracket is too far misaligned, there is nothing you can do to solve an AXS chain drop.

For those who have truly tried everything with chain drops and have made it this far, I know that's not what you want to hear. It sucks.

This is flashbacks to the Cannondale x pressfit BB30a creaking issue, and BB creaking in general. Which took years to come to light. Remember when everyone was saying "You just didn't press your BB in straight! Are you sure you greased it JUUUUUUST right? Have you tried rebooting your bottom bracket?"

And now, nobody questions it's a tolerance issue. In fact, parts manufacturers literally have businesses built around offering aftermarket bottom brackets because this issue continues to both be an existing frame problem, as well as a lingering fear from those who have been around press fit long enough that some customers select after market BB's as part of their build process.

So where does that leave you? Your options:

A) Change group set brands (the silent killer: Shimano's patents win, SRAM falls on the sword for frame manufactures).
B) Sell your frame, hopefully to a Shimano fan. Then roll the dice with a new one.
C) Try to fight for frame warranty. But burden of proof is hard.
D) Post your frame brand, model, frame size here.

With enough anecdotes, we can at least start to get some clues as to which manufactures don't play nice with SRAM.

Honestly, we've reached this point because the pandemic wiped out Shimano supplies which forced all kinds of frames x SRAM permutations to be built. And now these issues pointing to the frames are surfacing.

If that was all too verbose: The takeaway is BLAME YOUR FRAME MANUFACTURER.

btw

did rebooting your router work?

ghostinthemachine
Posts: 780
Joined: Thu May 07, 2015 9:18 pm

by ghostinthemachine

maxim809 wrote:
Tue Jun 07, 2022 8:51 am

If the frame's FD mounting bracket is too far misaligned, there is nothing you can do to solve an AXS chain drop.


If that was all too verbose: The takeaway is BLAME YOUR FRAME MANUFACTURER.
Except many of these frames are actually in spec, and aligned. And Shimano and SRAM have the same nominal spec (i just checked). Just measured slightly differently.

DaveS
Posts: 3922
Joined: Fri Mar 24, 2006 1:26 pm
Location: Loveland Colorado

by DaveS

When someone posts that their FD rubs in the 52/11, it's set up incorrectly. The cage must have 0.5 to 1mm of clearance. If it also rubs in the 52/17 it's set up incorrectly. It must not rub in the little ring and largest sprocket. Both limits are set incorrectly, probably in an attempt to stop chain drops. That's totally wrong. I'd try a different FD at the minimum to be sure that the problem FD isn't malfunctioning. The real problem is probably the chain rings. A Campy 12, shimano 12 or grx crank would probably work fine. No aftermarket chain rings for me.

Holding on to a FD that wants to rotate during the final tightening of the clamp bolt is not the answer. The cage needs to be set such that it ends up with the marks parallel to the big ring. I suppose that the marks could be mislocated. Early on, I remember not aligning both marks.

I measured the total side to side travel on my FD and got about 5mm. I measured off the side of my rear tire, using a mark on the tire to eliminate tire runout error. There's no rub in the 48/10 or 31/33. I have 415mm chain stays, but I've also had no rubbing on a Colnago C-RS with 405mm stays.

raggedtrousers
Posts: 416
Joined: Wed Dec 09, 2020 9:29 pm

by raggedtrousers

maxim809 wrote:
Tue Jun 07, 2022 8:51 am
Alright everyone. This thread is killing me. So time to spill the beans.

But first, my 3 reasons why this thread is crushing my soul. Skip below the line to dodge RAGE RANT... for more rage rant.

1. Half the people on this thread are genuinely having an AWFUL experience with SRAM's FD.

When you pay this much money, you expect the customer experience to be great. Instead, the unfortunate ones are double penalized by having to spend TIME fiddling with their FD at home. Driving your bike to every LBS in town so you can meet each of the mechanics who will surely provide the panacea to your problem. Who instead will eventually pull their hairs out chasing ghosts, just like the previous mechanic. So you go online to turn for help, and instead get ridiculed for asking innocent questions while carrying battle scars.

Hate to see this. Imagine how much you could have been riding your bike instead of dealing with nonsense.

2. Although some posters are well-intentioned and definitely trying to help, some are straight up patronizing.

"You are not following instructions!" Alright bro. One should consider that by the time someone is so deep into a problem that they're making a 'cry for help' post on a bice forum that looks like it's from circa 1980, they are probably NECK DEEP into their problem. And they probably know more about this than you, who happened to be lucky enough to avoid SRAM's FD problem and never actually had to struggle with anything to truly give any meaningful advice.

Tech support without understanding root-cause is basically, "Have you tried rebooting your router?"

3. Everyone be hating on SRAM. When SRAM is the victim. Like the customers whose struggles are real.

===================

The frame manufacturers are at fault for not building their frames to specifications.

Shimano owns numerous defensive patents that prevent competing group set manufacturers from easily making a reliable front derailleur.
Campy has figured out a way that works around these patents. SRAM has specifications that clearly state what is needed by frame manufacturers to get their group sets working flawlessly. However, some brands look to SRAM's specs as "optional guidelines" rather than HARD requirements.

Often the issue is that the FD bracket's pitch is angled out of tolerance. Ideally, SRAM would have a mechanism that allows them to finely adjust the FD's pitch after mounting. But they can't. SRAM can only provide specs to every frame brand, and cross their fingers the specs are followed. But a groupset company with 15% marketshare doesn't have the leverage nor enforcement powers to police every bike brand. Let alone inspect every frame that's popping out of every factory in the world to ensure no crooked frames reach customer hands.

If the frame's FD mounting bracket is too far misaligned, there is nothing you can do to solve an AXS chain drop.

For those who have truly tried everything with chain drops and have made it this far, I know that's not what you want to hear. It sucks.

This is flashbacks to the Cannondale x pressfit BB30a creaking issue, and BB creaking in general. Which took years to come to light. Remember when everyone was saying "You just didn't press your BB in straight! Are you sure you greased it JUUUUUUST right? Have you tried rebooting your bottom bracket?"

And now, nobody questions it's a tolerance issue. In fact, parts manufacturers literally have businesses built around offering aftermarket bottom brackets because this issue continues to both be an existing frame problem, as well as a lingering fear from those who have been around press fit long enough that some customers select after market BB's as part of their build process.

So where does that leave you? Your options:

A) Change group set brands (the silent killer: Shimano's patents win, SRAM falls on the sword for frame manufactures).
B) Sell your frame, hopefully to a Shimano fan. Then roll the dice with a new one.
C) Try to fight for frame warranty. But burden of proof is hard.
D) Post your frame brand, model, frame size here.

With enough anecdotes, we can at least start to get some clues as to which manufactures don't play nice with SRAM.

Honestly, we've reached this point because the pandemic wiped out Shimano supplies which forced all kinds of frames x SRAM permutations to be built. And now these issues pointing to the frames are surfacing.

If that was all too verbose: The takeaway is BLAME YOUR FRAME MANUFACTURER.

btw

did rebooting your router work?
Post of the year :beerchug:

My frame was a TCR Advanced Pro 21, and the FD was Force AXS, also Force AXS chainrings, 48/35. Nothing aftermarket or non-standard.

Roadbiker10
Posts: 495
Joined: Fri Apr 30, 2021 8:22 am

by Roadbiker10

DaveS wrote:
Fri Jun 03, 2022 8:09 pm
Chain length can only be changed in one inch increments and that cover 4T of sprocket. I have my chain length set for a 10-36, but use a 10-33. I just corrected the B gap and have no problems. As long as the chain doesn't hang loose in the little ring and 11T sprocket, there should be no problem. I don't stay in the little ring long enough to use the 11, except by accident.

Roadbiker10, are you using sequential or compensating modes, shifting at a low cadence, with high torque? Sram has good installation videos. Try fixing it yourself. It takes less time than driving to a shop.
It doesn't look loose, I'll put a pic.

No I have never tried those modes of shifting, I only use manual. Now that you say it. For example when I approach a hill, I sometimes let the cadence drop(low cadence higher pressure) before shifting down in the front so that I don't spin too easy when I go to the small ring. I have noticed it has dropped a few times in those situations.

So I guess I should first go to the easier gears on the back approaching a hill in the big ring and then go to small in front while spinning faster and then go to harder gears in the back fast.

I also noticed it happening mostly when going slow.

What about shifting front and back at the same time? Should that be avoided? I have been avoiding it the whole time, being afraid that would make the chain drop, but lately I have done it more and that wasn't causing it any more than avoiding it.

Having said all that. It has happened pretty much in all kinds of situations. Although I obviously haven't kept track of which situations it happened the most.

I guess I'll have to try myself at some point. But like I said, I don't trust myself at all with mechanical work. I am the guy who forgot to take the plunger out when bleeding brakes and soaked my shifter in mineral oil, which led to over 200 euros of cost to replace. I once turned the simple task of removing a rear axle on a RM Element into leading to it seizing since I put the tool in on the cassette side of the axle which turned into a nightmare to remove and had to get a new axle. Every time I tried adjusting gears(mechanical) myself, 90% of the time I managed to make it worse. And that's just of the top of my head, there's probably plenty more I screwed up.

Nevermind forgeting my front axle from the Addict on top of my car, riding of with it, it falling of on the road, someone riding over it. That cost me 80 euros plus 40 for adjusting the brake issues which arised from me doing a race with that run over axle.
1555110E-645E-4C46-9850-A3AFD6B3D4AF.jpeg
Scott Addict RC 20 2021
Ridley Kanzo Adventure 2022

Roadbiker10
Posts: 495
Joined: Fri Apr 30, 2021 8:22 am

by Roadbiker10

By the way. I was there today again for a third go, mostly for them to fix the chaincatcher. First time, they put it just as far from the ring that the chain slipped through. Now this time, they put it as close to the chain as possible without touching it. Conclusion, they had no idea how to install a chaincatcher. I'll post the pictures of the before and after, of the chaincatcher.

This might be a noob question. But is the chaincatcher supposed to just catch it from going further and damaging your frame, or by being so close to the chain, to prevent the chain from falling of at all?

Here is the before and after:
15E5F20D-8CF7-4269-BD83-520B96749119.jpeg
5F013538-BB1C-4E6E-87B5-20F387A38CB5.jpeg
Scott Addict RC 20 2021
Ridley Kanzo Adventure 2022

tomato
Posts: 729
Joined: Mon Jul 01, 2019 8:37 pm

by tomato

Roadbiker10 wrote:
Tue Jun 07, 2022 6:33 pm
This might be a noob question. But is the chaincatcher supposed to just catch it from going further and damaging your frame, or by being so close to the chain, to prevent the chain from falling of at all?
I'd vote for the latter.

Roadbiker10
Posts: 495
Joined: Fri Apr 30, 2021 8:22 am

by Roadbiker10

tomato wrote:
Tue Jun 07, 2022 6:45 pm
Roadbiker10 wrote:
Tue Jun 07, 2022 6:33 pm
This might be a noob question. But is the chaincatcher supposed to just catch it from going further and damaging your frame, or by being so close to the chain, to prevent the chain from falling of at all?
I'd vote for the latter.
If that's the case, then the problem is easily solved right?
That sounds too good to be true.

Btw, has anyone else had this problem on an Addict RC?
Scott Addict RC 20 2021
Ridley Kanzo Adventure 2022

tomato
Posts: 729
Joined: Mon Jul 01, 2019 8:37 pm

by tomato

Roadbiker10 wrote:
Tue Jun 07, 2022 7:43 pm
tomato wrote:
Tue Jun 07, 2022 6:45 pm
Roadbiker10 wrote:
Tue Jun 07, 2022 6:33 pm
This might be a noob question. But is the chaincatcher supposed to just catch it from going further and damaging your frame, or by being so close to the chain, to prevent the chain from falling of at all?
I'd vote for the latter.
If that's the case, then the problem is easily solved right?
That sounds too good to be true.
There are no guarantees in life.

DaveS
Posts: 3922
Joined: Fri Mar 24, 2006 1:26 pm
Location: Loveland Colorado

by DaveS

No matter how close the chain catcher is mounted, I've had the chain slip under it. It can make things worse.

raggedtrousers
Posts: 416
Joined: Wed Dec 09, 2020 9:29 pm

by raggedtrousers

Roadbiker10 wrote:
Tue Jun 07, 2022 6:00 pm

Nevermind forgeting my front axle from the Addict on top of my car, riding of with it, it falling of on the road, someone riding over it. That cost me 80 euros plus 40 for adjusting the brake issues which arised from me doing a race with that run over axle.
I've done this.

I went on a cycling holiday last year (in the UK). I arrived, took the bike out of the boot of my car... and couldn't find my thru axle. Thinking back, I'd obviously left it on the roof, and simpy driven off. So that was next morning taken care of, driving 100 miles round trip to a Giant dealer who had a spare in stock. :oops:

DaveS
Posts: 3922
Joined: Fri Mar 24, 2006 1:26 pm
Location: Loveland Colorado

by DaveS

I tried an experiment with one of my sram force axs and shimano grx equipped bikes. I deliberately tried to induce a chain drop by first turning the low limit screw by as much as a full turn, so I got chain rub in the little ring and third from largest sprocket. I also increased the gap by a full turn. No chain drops with either improper setting.. Then I tried turning the high limit screw to increase the gap between the FD cage and chain in the big ring and smallest sprocket. I made a full turn off and it still didn't cause a chain drop. I'd have to try really hard to create a chain drop.

I then put everything back to the normal 0.5 to 1mm gap at the big ring and no rub in the big/big.

by Weenie


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