Badger6

Hunted around for an answer to this question, and it is not exactly clear to me.

Context first: 11-speed SRAM XG1175 cassette (10-42), Shimano 11-speed chain), SRAM AXS X-Sync Road 1x chainring.

The chainring says something about flattop or eagle chain only. Fine, but when I lopped the 11-speed Ultegra chain onto the ring, it meshed (with no obvious issues). It's on a 1x set up, to it isn’t being moved on the front, and on the back the cassette/chain pairing have been perfectly fine over 10,000km (replaced of course).

So, 11-speed chain on this chainring…any experience with it?

FBinNY 

ANY 1/2" pitch of the correct width will work fine. Obviously SRAM has an incentive to try to convince their customers to spend replacement dough on their own products, but there may also be a legitimate reason for the recommendation. Besides carrying the load, index shift sprocket are shaped to optimize shift characteristics. That means the chains (ideally) should be matched so the plate profiles are the same.

I can't say how much difference the "wrong" chain may make, if any, or whether that difference is meaningful and how much (if any) shifting will be less than optimal, but I expect that it'll be minimal (if at all). in any case, nothing succeeds like success, so stay with what's been working fine for you so far.

FWIW - the flat top chain was designed to increase clearance on the sprocket side and facilitate chain dissengagement when shifting. Based on that logic, it MIGHT actually be more likely to come off the single sprocket than the chain you have now.

Badger6

So, to be clear...the business end (back) is a SRAM 11-speed cassette. I'm on the second cassette on this bike, and it's always been driven by a Shimano 11-speed chain. Zero issues back there.

The front end (party!) is where I'm wondering about the engagement/meshing of chain to chainring...I did my normal short commute (10km) this morning to work on it, and all seemed fine.

FBinNY 

As I said ANY chain of correct pitch and width will run on any sprocket* regardless of brand.

Chain and sprocket dimensions are highly standardized, so the only differences relate to shifting performance, which obviously doesn't apply to a single chainring.

*chainring is just another term for sprocket

Badger6

Before 12-speed…yes. But, today, in the 12-speed world, SRAM and Shimano chains are not interchangeable…despite the pins being the same pitch, and the chains using the same outer dimensions, the inner dimensions are different. This is clearly not a marketing gimmick since KMC 12-speed chains are sold for SRAM and Shimano and marked accordingly. That is what led to my question. Nevertheless, I now have about 100km on various surfaces, including some rough surface stuff, and the 11-speed Shimano chain is working fine, with the 12-speed AXS chainring.