SRAM AXS 2x users who are satisfied with your front derailleur: Enlighten me please

I know the AXS FD has a bit of a reputation, and based on my experience it’s well deserved. Anyone out there who’s installed and set up an AXS FD and feels like they’re getting crisp consistent shifts with no chain drops, can you share any tips or tricks?

Brief background: Longtime MTB/gravel/1x rider who has been riding more road, so I set up a bike with Rival AXS front and rear, 10-33 Red cassette and 46/33 Force chainrings on a Quarq 107BCD PM spider/Force cranks. I’ve built dozens of bikes and feel like I’m pretty technically proficient. I set up the FD using the SRAM setup tool thing, and followed SRAM’s instructions including these troubleshooting suggestions. Little dumb plastic wedge is installed.

Despite all this, I feel like I’m rolling the dice every time I shift from small to large chainring. Sometimes the chain doesn’t shift and instead grinds and jumps and I have to shift back to small and then re-shift. Sometimes the chain drops to the outside of the big ring. Even when it works it seems like there’s skipping and/or over-shift (i.e. I can see the chain being shoved past the big ring, but it catches the teeth before dropping.)

What am I missing? Do I need to further mess with high/low limit screws? I’ve seen suggestions that very small (like 1/4 turn) changes in these can be the diff between crips shifts and dropped chains, but I’m within the limits suggested by SRAM so feels like I’d just be turning them at random and hoping for the best. I honestly can’t think of what else to adjust, and would appreciate suggestions.

(I just rented a Shimano 11s mechanical equipped bike on vacation and it was made clear to me how much better Shimano is at this. But I’m sufficiently bought into the SRAM ecosystem on multiple bikes that I’d really rather not swap if at all possible.)

That’s not right. My Tarmac came with Rival and FD shifting has been fine with Red 46/33 crank. Last month I put a 48/35 crank on, and moved FD. Chain was just under 1mm, used the plastic thingy, etc. Shifting front was fine, rear was a little chunky in a couple mid cassette shifts. Had a shop look and they slightly adjusted yaw of front, so make sure the front is square(?) They also tweaked the rear B adjust because it was my first time and seemed like I had a lot of range to keep it in 5mm or whatever that measurement is specced at.

Very similar experience here. 1 out of 4 FD shifts the chain would drop, almost always on the inside, shifting from big to small ring. Going by SRAM set up instructions / videos did nothing. I resorted to eyeballing the whole set up and making super small adjustments. The high and low tolerances have to be very tight. I managed to get the FD to a point where a dropped chain happened about 1 out of 30 shifts. Best I could do.

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I will see if I can get it even better. I do get the occasional drops on the inside but they are very infrequent, like 1-2/months but I don’t have any noise yet either, so probably can make an even tighter adjustment

@Drew

Did you use the forward derailleur set up tool?

My Madone came with Force AXS, and it regularly threw the chain off to the outside. I did all the things, and got it down to once or twice a month. Then got sick of that and started tweaking the limit screw a tiny amount (way less than 1/4 turn) whenever it dropped the chain. It took a few times. Now I’ve had one dropped chain in the last 18 months (~9000 miles) or so, and haven’t touched a thing.

-Tim

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When you say “tweaking the limit screw”, which one and which direction?

Upper limit, tighten. Like 1/8 turn or so, sneaking up on the correct setting.

-Tim

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Oh, and one more thing: this only worked when riding in the world. I could not get the chain to drop on the work stand no matter how hard I tried. It was the right (wrong?) combination of…something that would only happen on the road.

-Tim

The only time I’ve had a drop was trying to shift to the big ring while putting power down, so it makes sense to me that it would be tough to make it happen on the stand.

OK thanks, good info. I’m gathering you want those gaps as small as possible, probably? And I’ve heard the suggestion that the FD doesn’t behave/position itself the same in the workstand as on the road, i.e. adjusting during a ride might make sense.

All in all seems like more voodoo than science, but I’ll give it a try.

I do wonder if I just have poor/unpracticed front shifter technique. I certainly don’t shift under full power but am I mistiming my soft-pedal?

(It can’t possibly be this complicated. Shimano FDs shift under load while covered in mud on gravel roads EVERY.SINGLE.TIME.)

I’ve had Force or Red eTap since 2016. Just a N+1 observation: The AXS flat top chains seems to be less forgiving if too long or short. No idea if this would contribute to your problem but, it definitely seems like a factor in crisper shifting. From time to time I’ll throw the chain off the big ring. In each case the FD was not aligned or straight.

The only other issue I’ve had, which again doesn’t really help solve your issue, is the rear Force cassette needed to be warrantied as some of the cogs were not straight. Check your rings for something similar maybe?

Maybe not voodo, more like finesse. The crazy tight tolerances of cramming 12 speed cassettes into the same space as 11spd makes everything more sensitive. And disconnecting the feel of the shift from your fingers on the lever means you don’t learn (and can’t affect) the nuances of a good shift. The up side is that once it’s done, you never have to touch it unless you remove the derailleur.

-Tim

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I never had any issue over the last couple of years. I have to say though that all the maintenance was done by LBS.

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Yea this is the issue with them. The ratio on this adjustment screw is way too high. The working window between not changing, good, and throwing a chain is a fraction of a turn

Are you using the setup tool?

It’s a specific template that you mount on the chainring to get the FD spacing exactly right.

I had my shop do the original install, and then upgraded to the WIDE spacing. They used the setup tool both times and it was PERFECT. When I tried to set up the WIDE version without it, the shifting was a mess.

Have you tried bringing it to a shop? The nice thing about electronic - one it’s adjusted, it’s set. No cable stretch or anything…

Mine dropped twice (rival) early on and then never again. Both times I foolishly was crosschained and it dropped inside when going directly to the small while on the biggest cog. I stopped doing that :upside_down_face:and haven’t had a problem since. Force on second bike has yet to have any issues.

I gave up and installed a chain catcher. Zero drops since the install, not ideal but it works.

My force axs fd has only dropped around a dozen times in the last year, and always to the inside. Until last week I had 2 drops, one of which was to the outside. I suspect it’s time to replace the chain. I’ve been loathe to fiddle with the setup because it works just good enough that the over/under on screwing it up is higher than letting it alone. Usually the drops were under load or a quick cadence jump, which I could just be more mindful of while riding. I didn’t install it, so no idea if voodoo was required to get it setup this way.

tldr: any chance the chain is stretched?

How many miles on the chain, and how well have you kept up with lubrication? Your best bet is to just get a chain checker, but be sure it’s compatible with flat top SRAM. The rollers are bigger, so 10/11 speed checkers won’t work.

-Tim