from what I understand, the difference is mainly in the weight/material. I’ve been running NX for over a year now and I’m happy with it. personal opinion, save the cash and go buy some more beer instead haha
My daily ride is GX, but my only experience with NX has been rentals, demos, buddy bikes, etc. One thing I noticed was NX didn’t handle loaded downshifts as well. But coming from riding XT for years, I may be pushing it a little for both NX and GX. Although, my GX does OK trying to downshift while on a steep technical standing climb. Other than that, I don’t have a lot to go on for comparing GX/NX. Having said that, I didn’t notice any real issue with NX in my limited experience with it… works as advertised. I don’t measure grams, so have no idea about weight differences.
Maybe someone else can expand on their NX experience, but my thoughts on GX are (coming from XT): I’ve got close to 10 months on GX now. 2018 model. The usual abuse, including at least two (that I remember) rock slams causing pretty decent gouges into the derailleur’s aluminum body. Stuff gets an occasional cleaning and oiling once in a blue moon. Loaded downshifts work pretty good considering the angles needed to reach the span of a 12 speed cassette. Upshifts are quick and solid. I’m not crazy about the shifter. Thumb press downshift, index finger pull upshift (only). It works fine, but I prefer the two way shifting using either finger like XT does. Even with slamming the rear derailleur into rocks, I haven’t had the need to make any adjustments. It’s held true, including throughout break-in. The only issue I had was one of the idler gears nearly seizing. Had to take it off, clean it out. All in all, no real complaints. And to be honest, works as well as XT. Just different ergonomics. As for wear… I don’t see any unusual wear patterns that wouldn’t be expected.
The main difference is weight of the systems, which is mostly in the cassette. Lighter materials used in GX versus NX. The only complaint I have heard about GX is that the cage arm is more prone to bending versus the NX. Don’t know if they solved that issue. I would customize if I were to build up, go with GX cassette and shifters and NX derailluer and crankset. I have XO which came stock on my bike and it has been flawless with no adjustments for a year now.
Thanks for your replies. I’m not a racer and don’t plan to race unless I do a one off race so weight really isn’t a concern. The trails I primarily ride are singletracks and have some drop offs, plenty of rocks, roots, etc. so I guess my greatest concern would be the functionality and durability of each. The price difference from NX to GX isn’t too much so that isn’t a concern either. I’ve heard different opinions and most seem to come down to preference. I ask because I’m in the market to buy a new bike and was deciding between one with an NX groupset and another with the GX groupset and different shocks on both and the overall price difference is $500. Thanks again for your replies.
The Eagle NX drivetrain is designed for Shimano HG hubs and has an 11-50 cassette 455% range. The Eagle GX drivetrain is designed for Sram XD hubs and has a 10-50 cassette 500% range. So you want to make sure you buy the right cassette for your hubs. I do think that the wider range of the of the 10-50 cassette is worth paying more. I don’t think 1X drivetrains really got good until they had a 500% or greater range. According to Sram, all the Eagle drivetrains are mix and match so you could use a GX 10-50 cassette (if you have the XD hub) with an NX drivetrain and save a few bucks. However, given that the difference between the two drivetrains is only about $100, I would just go for the total GX drivetrain if I had XD hubs.