I don't know the answer but a common question that comes up with similar issues is if you're sure the cassette is fully seated. The typical recommendation is that since there's a lot of friction installing an XD cassette, the lock ring needs to be tightened sufficiently to fully seat the cassette, which best done with a torque wrench.

 

I went out and pulled the cassette, cleaned/greased, and reinstalled to 40 N-m torque. No dice.

Thanks for the suggestion, though. That thing needed to be cleaned.

 

I found a compatibility chart on SRAM's website. Going by that, I'm boned. But then they list XD cassettes in their road 1x pages. Ugh.

 

SRAM road 1x groups use mountain XD cassettes. For example the XG-1150 comes both with Rival 1, and GX. It's not a road cassette. Actually, first it was a GX cassette. There is also the 1175 and 1180, which is a Force, or an X1 level cassette in theory. Again, it's shared with MTB stuff.

See here:

https://www.sram.com/sram/road/family/sram-rival-1

https://www.sram.com/sram/mountain/family/gx

The cassette on your build which should be a PG1130 is also shared with NX, again, MTB group.

Personally I used an 1150 and 1180 with Rival 1.

The higher level Cutthroat builds use XD cassettes like the 1150. Which again is just a regular mountain cassette. I'm pretty sure there is no such thing as a "road" 10-42 XD cassette.

The spacing between the cogs is the same on SRAM road and MTB cassettes. There is a new standard called XDr (XD road), but you don't need that, and if I start explaining what it is i'm just gonna confuse you more.

Hate to be that guy, but you're doing something wrong. First of all, low gear = biggest cog, high gear = smallest cog. So if you adjust the low limit screw, that has nothing to do with the derailleur shifting onto the 10t.
Release the cable completely, then back out the high limit screw so the derailleur can shift onto the 10t cog. Attach the cable again, then try messing with the cable tension a bit, then shift into the 42T, adjust the low limit screw. B tension is VERY important with SRAM RDs, don't forget that, set it correctly!
There are tons of tutorials on youtube. You can watch tutorials for SRAM MTB stuff too, it's basically the same as 1x road in terms of setup.

The XD cassette being closer to the dropout is not an issue, that is what the limit screws are for. On my bike the chain is almost touching the dropout on the 10T.

 

Hate to be that guy, but you're doing something wrong. First of all, low gear = biggest cog, high gear = smallest cog. So if you adjust the low limit screw, that has nothing to do with the derailleur shifting onto the 10t.
Release the cable completely, then back out the high limit screw so the derailleur can shift onto the 10t cog. Attach the cable again, then try messing with the cable tension a bit, then shift into the 42T, adjust the low limit screw. B tension is VERY important with SRAM RDs, don't forget that, set it correctly!
There are tons of tutorials on youtube. You can watch tutorials for SRAM MTB stuff too, it's basically the same as 1x road in terms of setup.

The XD cassette being closer to the dropout is not an issue, that is what the limit screws are for. On my bike the chain is almost touching the dropout on the 10T.

Well. this is embarrassing as hell. I screwed with it for a good 45 minutes last night and couldn't get it to work. I read your post and decided to go through the setup routine from start, one more time. And hey, it works perfectly now. I have no idea what I was doing wrong last night. I wasn't even drinking, so I don't have that as an excuse. And that's why I'm not a bike mechanic.

Thank, HollyBoni. I think I just needed to know that it does work.

 

"... I wasn't even drinking..." Well, right there's your problem-that's a two-beer job.