AXS Flattop chain/chainring compatibility

[p nut]

I’m cobbling together a dropbar MTB. I had some issues with the chainring clearance. It only cleared a measly 32t but I was able to fit a 36t by using a 3mm offset chainring (frame has 142mm spacing).

The chainring I purchased is SRAM Eagle X-Sync 2. I’m reading some conflicting info of it working with SRAM flattop chains. I believe officially, it says no. But some have said it works.

I should have my AXS XPLR groupset in the next week or two. I wanted to make sure I had all parts on-hand to have the build go as smoothly as possible. Thanks.

[kppolich]

https://forums.thepaceline.net/showthread.php?t=290402
For a crankset and chainring (36T) that will work with the included flat top chain.

But to more clearly answer your question.

The flat top chains I believe are required for road/gravel cassettes and RD's.

If you are running a mullet setup (XX1, XO1, GX) AXS RD and cassette, I believe you'll need the non-flat top chain.

Here's a useful doc capturing compatibility strictly for AXS:
https://www.sram.com/globalassets/do...bility-map.pdf

[AngryScientist]

This of course does not directly answer your question, but I'm successfully using a flat top chain on both a 2x Campag-12 chainset and also a Campag Ekar chainring. Moral of the story - don't believe everything you read about incompatibility.

[p nut]

Thanks. The group I’ll be running is Rival AXS XPLR (1x). I guess the best thing to do is just wait for the groupset and test fit.

kppolich - It’s going on a MTB so won’t fit road cranks. Thanks though.

[callmeishmael]

I have AXS XPLR with Rotor (round) rings. As Rotor don’t officially make AXS compatible 1x rings, I called them for advice. They told me to run an Eagle chain. The result was acceptable shifting but a reluctance to drop down to the lowest cogs and a bit more noise than ideal.

As an experiment, I swapped in a Force flat top chain. It shifts perfectly and is much quieter.

[p nut]

Well, got my answer. Does not work.

[EB]

A wolf tooth drop stop B chainring will work with those chains.

[kppolich]

SRAM Eagle Chain should work with that setup.

[AngryScientist]

wow that's a new chainring? that is some seriously aggressive shaping on those teeth.

[p nut]

Eagle chain will work with the chainring but not with the XPLR RD (I don’t think?)

Both chainring and chain in picture are brand new.

I just emailed Wolftooth to see if they have a DM, 36T, Dropstop B with 3mm offset.

[kppolich]

Ah yes, XPLR RD needs a flat top chain.
Eagle chains are only compatible (per SRAM) with MTB RD's
https://www.sram.com/globalassets/do...bility-map.pdf

I wonder if DUB Wide would clear the chain stays and chainring clearance.

[p nut]

Wolftooth emailed and said they do not make a Sram DM chainring with Drop Stop B.

Guess this means I need to buy an Eagle RD and chain. I’ve got a Force AXS cassette which means I need to get an Eagle AXS cassette?

[callmeishmael]

Originally Posted by p nut

Eagle chain will work with the chainring but not with the XPLR RD (I don’t think?)

Both chainring and chain in picture are brand new.

I just emailed Wolftooth to see if they have a DM, 36T, Dropstop B with 3mm offset.

An Eagle chain works ok with an XPLR RD. Shifting to the smallest 2 sprockets was sluggish but otherwise it was fine; less smooth and a bit noisier than with a flat top, but functionally sound.

[p nut]

Originally Posted by kppolich

I wonder if DUB Wide would clear the chain stays and chainring clearance.

DUB wide is the crankset? Chainring is the same, correct? This is on a MTB frame so I don’t think that’ll work.

Originally Posted by callmeishmael

An Eagle chain works ok with an XPLR RD. Shifting to the smallest 2 sprockets was sluggish but otherwise it was fine; less smooth and a bit noisier than with a flat top, but functionally sound.

That may be my only solution short of buying a new RD and cassette. Thanks.

[p nut]

Just as an update and reference for posterity: I was able to get a hold of a Sram spider (actually a whole crankset). See this thread for important compatibility info (thanks kpploich):

https://forums.thepaceline.net/showthread.php?t=290999

After installing the spider, I left the 36T chainring the crankset came with to check clearance. Luckily, about 2mm of clearance so it’ll work.

The plan was to then get a Wolftooth 110bcd chainring, which comes in Drop Stop B. I will probably still do that but out of curiosity, I tested the flattop chain on the 11sp chainring. Fit is great. I’m sure chain retention won’t be as good, as it is not N/W. But it at least works.