I’m playing around with a 1x12 Sram XPLR setup on a 2018 Specialized Roubaix (back when the Roubaix was still a road bike and not an all-road/gravel-lite bike). Because of the terrain around me, I’m running a 44t Wolftooth chainring (specifically with the tooth profile they list for use with a flattop chain) and a 10-44 cassette. I’ve played around with the derailleur and chain length, but it feels terrible in the biggest three cogs. In the stand, there is so much resistance while spinning the cranks. When I look down at the chain when I ride, the chain line is terrible in those cogs (running a waxed Force chain). I checked the frame specs, and the chainstays are 415mm, which is the minimum recommended by Sram for XPLR. Is this a big deal? Any tips on improving the feel, or is this just a consequence of going 1x? I know some of the Sram sponsored teams sometimes run a 1x setup, so I would guess they tested and thought advantages outweigh the disadvantages.
The only thing I can think of changing would be putting on a Sram chainring. I’m skeptical that would make a huge difference and I don’t want to spend the money (those things aren’t cheap) without some confidence that it would help.
That sounds a bit more extreme than is typical. I run Transmission on my gravel bike, and while going to the 52T has noticeable drag, it’s pretty smooth by feel/sound one cog down in the 44T. 425mm stay length for me.
I doubt it’s the tooth profile of your Wolftooth ring. But you could have a chainline a bit off depending on what crank setup you’re running? Is it new XPLR Road Wide crank?
Is it possible that the chain might be rubbing against something as your rotate the cranks? To rule out the obvious, did you adjust the FD’s position when swapping to the 1x chainring?
The minimum chain stay length is based in part on tooth profiling. Chainring teeth have all sorts of cuts and chamfers to give the chain clearance when the chain is bent to extreme angles. An aftermarket chainring with different tooth profiles will yield different amounts of clearance so the SRAM minimum chain stay length is irrelevant. In my experience the term “compatible” is used very loosely in the world of chainrings. When it comes to 12 speed drivetrains, especially 1x, I have yet to find an aftermarket combination that is as smooth as full Shimano or full SRAM.
I’m running Eagle 1x on a 408mm chain stay bike. There is drag in the 52T but the rest are fine. Definitely something off if you’re getting drag on top 3 cogs with your setup.
I’d double check that it’s actually chainring/chain interference and not something else before spending money.
Remove the chain and make sure all the spinning parts (BB, pedal, rear wheel, free hub, r. derailleur pulleys) are smooth, straight and aligned. If it’s actually chainring/chain interference, you’ll often feel or see vibrations in the chain as each link notches into the teeth.
