Darth Lefty 

I don't know if you all have noticed, but several bikes this year have come out with a parts-bin 1x10 or 1x11 setup built around the big new Sunrace cassettes, and decent but not expensive derailleur, shifter, crank etc. SRAM has now countered with a similar approach but all in one groupset, called NX. In a notable departure for SRAM, the cassette is Shimano freehub compatible, with an 11 top cog, much like the Sunrace.

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

SRAM NX drivetrain most affordable 1x groupset yet - Mtbr.com.

FrozenK

538 gram cassette weight= ouch. There goes most of the weight savings from going 1x11. And you lose the 10t cog, which means you lose quite a bit of top end. I can see the appeal for people who don't want to get an XD driver, but on the other hand why not just get an XT cassette?

Darth Lefty 

I know, right? Even the Sunrace versions are several ounces lighter, even lighter yet at 10-speed and/or with an aluminum bottom cog.

The Marin Pine Mountain 1, a bike I've been eyeing, has an X7 RD, an X5 shifter, an unbranded 32 NW ring and the Sunrace 10x11-42 cassette. It looks like a pretty good combo to me, I might try it if my current MTB would have the good grace to die :-D

Maelochs

XT cassette only goes to 40 teeth I think.

Canker

XTR only goes to 40. SRAM had to put out a full group for OEMs including the cassette, doesn't mean you have to use it. Just buy the XT cassette.

FrozenK

No, XT has a 11-42 option and weighs about 100 grams less. SRAM's 1150 cassette (GX) weighs 394 grams in 10-42.

gsa103

An XT cassette is about $80 by itself. Hard to hit a $300 groupset price with hardware that expensive.

I think it'll be huge benefit not for mountain bikes, but for commuter bikes. 46t crank+11-42 cassette covers a nice gear range for a flat bar commuter, and is much simpler and cleaner.

Darth Lefty 

The Shimano cassettes have a nicer sequence thanks to some unusual tooth counts. The Sunrace ones tack a 36 and 40 or 42 onto a familiar 9x11-32 sequence. I hadn't yet looked at the NX sequence.

FrozenK

The gear spread on the NX seems very similar to Shimano XT.

I have about 400 miles on the Corvus using a GX drivetrain, my first experience with 1x11, and so far so good. At the top end the 10 to 12 shift can feel like too big a jump, but 99% of the time it isn't noticeable. Only when I'm trying to hammer on a flat section. Other than that the gears are nicely spread.

I'm not convinced that it would be enough of an improvement over the 2x10 I'm running on the Yeti to justify upgrading. But for winter biking I'm sold. You can fit bigger tires without chain rub. Less things to worry about freezing/failing. And with a double you end spending more time pushing a taller gear to avoid shifting up front -or at least I do- which some times means spinning out. In the summer I can usually push a taller gear. But we'll see.

And for beginners I think 1x drivetrains will be great. No need to worry about front shifting at all.

Darth Lefty 

Looking at it now in detail. Most of the 42's have a slightly awkward 4-4-6 tooth spacing at the bottom shifts but the Shimano uses a 37 to get 4-5-5, smoother.

Shimano's 40 has a lot of oddball cogs to make it more evenly spaced than the Sunrace version that uses the familiar 4 spacing.

All the 11-42 cassettes have the same cogs as an 8x11-28 and 9x11-32.

SRAM's 10-42 has the same cogs as a 9x12-36 with a 10 added to the top and 42 to the bottom.

[TABLE="width: 398"]
[TR]
[TD]Shimano 11x11-40[/TD]
[TD="align: right"]11[/TD]
[TD="align: right"]13[/TD]
[TD="align: right"]15[/TD]
[TD="align: right"]17[/TD]
[TD="align: right"]19[/TD]
[TD="align: right"]21[/TD]
[TD="align: right"]24[/TD]
[TD="align: right"]27[/TD]
[TD="align: right"]31[/TD]
[TD="align: right"]35[/TD]
[TD="align: right"]40[/TD]
[/TR]
[TR]
[TD]Shimano 11x11-42[/TD]
[TD="align: right"]11[/TD]
[TD="align: right"]13[/TD]
[TD="align: right"]15[/TD]
[TD="align: right"]17[/TD]
[TD="align: right"]19[/TD]
[TD="align: right"]21[/TD]
[TD="align: right"]24[/TD]
[TD="align: right"]28[/TD]
[TD="align: right"]32[/TD]
[TD="align: right"]37[/TD]
[TD="align: right"]42[/TD]
[/TR]
[TR]
[TD]Sunrace 11x11-40[/TD]
[TD="align: right"]11[/TD]
[TD="align: right"]13[/TD]
[TD="align: right"]15[/TD]
[TD="align: right"]17[/TD]
[TD="align: right"]19[/TD]
[TD="align: right"]21[/TD]
[TD="align: right"]24[/TD]
[TD="align: right"]28[/TD]
[TD="align: right"]32[/TD]
[TD="align: right"]36[/TD]
[TD="align: right"]40[/TD]
[/TR]
[TR]
[TD]Sunrace & SRAM 11x11-42[/TD]
[TD="align: right"]11[/TD]
[TD="align: right"]13[/TD]
[TD="align: right"]15[/TD]
[TD="align: right"]17[/TD]
[TD="align: right"]19[/TD]
[TD="align: right"]21[/TD]
[TD="align: right"]24[/TD]
[TD="align: right"]28[/TD]
[TD="align: right"]32[/TD]
[TD="align: right"]36[/TD]
[TD="align: right"]42[/TD]
[/TR]
[TR]
[TD]SRAM 11x10-42[/TD]
[TD="align: right"]10[/TD]
[TD="align: right"]12[/TD]
[TD="align: right"]14[/TD]
[TD="align: right"]16[/TD]
[TD="align: right"]18[/TD]
[TD="align: right"]21[/TD]
[TD="align: right"]24[/TD]
[TD="align: right"]28[/TD]
[TD="align: right"]32[/TD]
[TD="align: right"]36[/TD]
[TD="align: right"]42[/TD]
[/TR]
[/TABLE]

FrozenK

So the only difference between the Shimano 11-42 and NX is the 37t on Shimano vs 36t on SRAM? I doubt you'll be able to tell the difference at all.

Darth Lefty 

Yes, it's more of a grams-per-dollar decision