BrazAd

Okay gang, someone explain the benefits of 1x over 2x, please.

I figure - 2x means closer ratios between gears and twice as many options.

No front derailleur = less weight, but most of us wouldn't miss those 28 paperclips anyway. 1x means the gear spread from gear to gear is farther apart. You have fewer options.

What am I missing? This isn't a troll thread, I'm sincerely asking. I'm sure I'm missing something in order to understand why this is a "thing", but I don't know what it is.

TIA,

Gary

base2 

Nope. You've pretty much got it.

2x, in addition to closer ratios, & more of them, also offers a greater total range. With some obvious expensive exceptions. I'm sure they're probably up to 9-56 tooth, $500 wear-item cassettes by now, just to do what 2x & a $50 cassette has always done.

I'm dubious of the derailleur capacity & cage length in such a (wide range 1x) scenario...That's a lot of leverage on the derailleur hanger & asking that long cage to hang down that low to be snagged by a bit of trail hazard is asking for problems, IMO.

3x tends to have even greater range & lower necessary derailleur capacity than either 1x or 2x, but that ship has sailed.

dwmckee

It is not that one is better than the other, just that roadies that cross over to gravel are more comfortable with the 2x they grew up with and mountain riders that cross over to gravel like to stay with the 1x they cut their teeth on.

Rolla

Not a dumb question at all, but there have been SOOOO many threads on this subject, I just can't.

chaadster

If you’re a newbie. When I cut my MTB teeth, there were only 3x.

But to the OP, yeah, I think 1x is a rather silly trend. Earlier today, in another thread, I was recalling a bike I had in 1980 which was a 1x2, but the two were up front! What would life be if everything stayed the same, right?!

DorkDisk

MTBs drove 1x to mainstream, and there you will find many benefits for frame design when you remove the front derailleur and have one chainring.

Fentuz

yes, this is what I think too...

I have a road biased bike and I set it up as 2x9 (39-53 x 11-25) because on the road, I wanted to keep the same cadence range and swap gear quickly, all nice and smooth.
On the gravel that goes on MTB trails, it is 1x11 (XC setup) because 2x would not work; when I climb a narrow (1.5m wide) rocky hill that keep changing inclines and can go from grippy to slippy, I don't really have to time to go through a closed ratio cassette and a chainring swap...

if the OP needs are road baised, 2x9/2x10 is a good cost effective option
if the OP needs are XC baised, 1x11/1x12 is definitely better

chaadster

Perhaps for swingarm design suspension frames, but not so for gravel bikes…as we know them.

Gravel 1x is a trend born from a fad, not a trend born of necessity.

DorkDisk

That's what I said, its the origin of 1x; it answers the OP's question of, "what am I missing?".

Then it "crossed over" to "gravel." Because it exists?

chaadster

There is, of course, no reason a 2x cassette needs be any different to a 1x cassette.

It may be better to have more or less closely spaced gear ratios for a particular user in a particular circumstance, but no gearing system is going to be optimized for every possible rider and circumstance. We can either provide more gearing options to cover more possibilities, or narrow the intended use range and gear for a more specific conditions.

That’s the question. Why? Why is 1x “definitely better”? It seems like your main point is that you “don’t have time” to shift a front derailleur??

It’s hard to imagine that’s always true, but I dunno how or where you ride, but it does raise the question why not ride an MTB…or is a drop bar MTB a gravel bike?

It’s all just a matter of definitions and particular user needs (i.e. how and where they want to ride), it’s not at all a matter of 1x or 2x being intrinsically better, something I think we are in agreement on.

For me, as a heavy but strong rider on rolling terrain, I see huge swings in speed constantly, and want to have as finely tuned gearing as possible so I can optimize my output for the competitive, fast group riding I do. It’s mostly on dirt roads, followed by pavement, with only occasional, small sections of track or trail. My fitness, as well as surface conditions, swings seasonally, so in winter and spring I want lower gearing than that which I’ll be using on the same rides in mid-summer. Given my needs and abilities, only 2x gives me the gear range to work whenever I want to.

Every rider needs to make that sort of assessment in order to determine what kind of drivetrain layout is best for them.

chaadster

I took the OP to be wondering why 1x gravel is, as they phrased it, “a thing,” because gravel bikes don’t have swingarms. I don’t know that the origin story of 1x speaks to that or speaks to the OP’s understanding that 1x presents fewer gearing options or why that should be desireable.

StanSeven

Ok guys. I cleaned up a couple posts on arguing and insulting. Let’s keep this civil. The original question is interesting to many and not everyone here is a 20 year cycling veteran. Thanks.

ClydeClydeson

• Lack of a front derailleur frees up a lot of design constraints re. seat tube placement (or if one is included at all), BB spindle length.
• Chainrings designed to encourage the chain to jump back and forth also (surprise!) encourage the chain to jump off or not engage correctly some non-zero percentage of the time.
• weight isn't a big part of the issue - 1X drivetrains usually have absurdly large cassettes compared to multi-ring setups, and 1x is also used often on bikes that are not really sensitive to small weight losses, like fat bikes and DH or Enduro bikes. The lightest road bikes still use 2x drivetrains.
• futzing with two shifters can leave your drivetrain knotted up when trying to make too many changes at once; one shifter that can access all drive ratios sequentially does not have this problem.

mstateglfr 

If you do the math, 1x really isnt lighter than comparable level 2x. It saves a front derailleur, some cables, and some left shifter internals...but it replaces that with a massive cassette. Thru the last few years I have found examples where 1x is a handful of grams lighter(like really a handful), even with 2x, and slightly heavier than 2x.


1x is really good for people who cant conceptualize how gears at two different points work. Just eliminate the front variable and go 1x for simplicity. Shifting jumps are bigger, but I dont think these people care.
1x is really good for MTB and CX because mud isnt trapped as easily in the bottom bracket joint and there is left fiddling to get good gearing when inclines are sudden and steep.

I dont find value in 1x for my gravel bike because it is just a road bike for gravel roads. A slightly easier geared 2x drivetrain is all I need. I like the smaller jumps and use my gravel bike on pavement to get to/from gravel since...its still a road bike.
If I bought a gravel bike that I use exclusively to underbike on singletrack, maybe 1x would be my choice.

Fentuz

Well, I won't go into details as I think others mentioned things like narrow wide keepin stuff is position and better when covered in mud etc. and yes I don't the time to shift quickly in difficult terrain.
Ultimately, manufacturers are not idiot and on XC bike, they go 1x. on road, they go 2x although some TT are 1x... @ Tokyo game, I didn't see XC mtb running 2x...
Gravel bikes are filling such a wide gap between XC mtbs and road bikes, it is "normal" that depending where the model is in between XC and Road, its transmission will be biased accordingly.

msu2001la

I'm surprised no one has mentioned tire clearance (or maybe I missed it). On some gravel/cx frames, the FD is a factor and 1x provides more clearance than 2x. Also worth noting that 1x setups can use a narrow-wide chainring, which helps with chain retention - particularly when combined with a clutched RD.

I like 1x and use it on both my CX and gravel bikes, which also do double duty as road bikes. I live in a flat area and don't need climbing gears, so I can run fairly narrow range cassettes (11-32 is plenty, I also use 11-34).

For me, it's more that I just don't really need 2x. On my 2x road bikes I almost never used the small ring. The large ring on a compact crankset plus an 11-25 or 11-28 road cassette basically meant I used the big ring for 90% of my riding, so why not ditch the FD and extra chain ring, use an 11-32 or 11-34 instead? The fact that the 1x provides better mud clearance, chain retention and frees up some space on my frame is just added bonus.

Don't get me wrong, if I lived in a mountainous area, I'd definitely want 2x on both road and gravel bikes. For flatland riding though... 1x is great.

chas58

I think you got it above. It was "invented" for MTB because it freed up frame design options.
downsides: More wear and tear on chain/chainring/cassette, bigger jumps between gears, you REALLY need a clutch on that derailleur.
The biggest benefit (thanks MSU) is probably that you can use wider tires. With a road Q factor and 2x, you really can't go beyond 40mm (38mm to be ISO compliant). You can also use a narrow/wide chain ring to help keep that chain on.

But the debated downsides are often trivial. Realistically,

1x is

• just easier mentally for a newbie.
• good for people who ride solo or casual group rides (where cadence/speed isn't critical)

2x is

• Good for people who REALLY care about their cadence
• Good for people who do fast group rides (where you can't easily choose your cadence and speed).

just a clarification -2x doesn't have twice as many gears. It roughly has 30-40% more as there is a lot of overlap.
(as noted above, 2x can be lighter - mine is).

BrazAd

OP here - wow, thanks for the great replies so far!

Background: Cycling seriously for 4-1/2 years. I ride about 6k annually on road and 1k+ on dirt roads with a gravel bike. I don't ride MTB or know much about them at all.

I've been shopping for a new gravel bike and have been surprised that so many are 1x. The one I am buying this week ('21 Salsa Warbird) is a 2x (like my Cannondale Synapse road bike) which gives me lower gearing options for steep hills.

I appreciate all the input - I'm learning, every day!

Gary

chaadster

Yeah, assuming 700c, but a couple of points:

I don’t think it’s unusual for standard Q factor setups to run +40mm rubber, is it? 3T Exploro for example, can run SRAM AXS 2x with 50mm tires, and even 55mm with the Wide AXS FD and 43//30 Wide crank setup (https://blog.3t.bike/2020/05/14264/g...l-sram-gravel/), albeit the latter with a 5mm sacrifice to wider Q factor. My own T-Lab X3 runs 42mm but can clear up to 45mm.

The other point is that, if tire width is of primary importance, 650b wheels can be run with rubber in the +50mm range on the same drivetrain setups as the above 700c examples.

I think sacrificing gear range for tire width is not necessarily a tradeoff which needs made. Even with regards to Q factor, it seems inconsequential to move from 150mm road spacing to 155mm to accommodate extra FD space when we ride around on 170mm spaced MTBs all day…. Point being, it’s hard to complain about lost aero benefits from wider Q factor when pushing fat, 2.3” rubber down a trail.

mstateglfr 

My old gravel frame uses a 68mm shell and 130mm OLD, but fits a 50mm 700c tire and wheel.
My current gravel frame uses a 68mm shell and 142mm OLD, but fits a 47mm 700c tire and wheel.

Rolla

Anything that does away with the front derailleur represents an advancement for mankind, IMO.

rdecredico

The only reason front derailleur exist was to give more gears back when the largest cassette a wheel hub could handle was five cogs. Now that we can run a 11+ cassette the 2x and the 3x really only need exist for hyper specific applications.

The modern 1x provides plenty of gearing for all but a few that are working at extreme ends.

Also, this idea of closer gaps is silly. The gearing is not sequential on a 2x and in order to enjoy these 'close ratios' on a 2x one must noodle around both derailleurs and this is highly inefficient. It often involves skipping the rear cassette three cogs while droping from large to small on the front.

People that talk gear gaps on 1x are myopic. The only thing lost on a 1x is higher end stuff over 110 gear inches.

scottfsmith

I don't think anyone above is talking about the close ratio you are referring to. The 'close ratio' is even if the front derallieur is not moving. If you only have 11 gears going from 11-42 vs 11-30 you will have closer gears on the latter. Here is a Shimano 11-42: 11-13-15-17-19-21-24-28-32-37-42. Here is an 11-30: 11-12-13-14-15-17-19-21-24-27-30T. Now lets compute the tooth difference in each shift on these. 11-42: 2-2-2-2-2-3-4-4-5-6. OK now for the 11-30: 1-1-1-1-2-2-2-3-3-3. Now comparing the two you can see that on almost half the gears the 11-42 has double the gap on a single-gear shift compared to the 11-30.

ericcox

I'm in a similar boat. My area has some short hills, but on the road bike I am very rarely in my small ring. My CX bike is 1X with a 11-32 cassette. I had been using it on gravel and was fine 95% of the time but did want a bigger bailout gear. I just got a new gravel bike with XPLR on it; the bottom half is pretty closely spaced. The only big jumps come at the top. When I need the bailout, I don't mind the big jump.

I really think it depends on the use case. I have 42t chainring with a 10-44 cassette that looks like this: 10,11,13,15,17,19,21,24,28,32,38,44. The 42-10 is big enough for the occasional group ride on the road (I use the gravel bike for commuting - occasionally hop in a pre-work group ride with it), and I can manage my cadence pretty well at speed and in races. Yeah, the bailout jumps are big, but when I need the 38, I don't mind so much. If I were in a hillier region, I may feel differently.

In short, I don't think there is one answer for everyone. A lot of people will benefit from and prefer 2x. That's fine! Many of us prefer 1x on gravel and that's fine too. I'll stick with 2x on the road for the time being.

mstateglfr 

newb coming in strong with the heat!
I will just add that in the middle 8 or so cogs on my 2x11 gravel bike, the jumps are smaller than if I had a 1x11. Its sequential, unlike your claim, and its very much real.

I run 48/32 with 11-36. That gives a 121.19 - 24.74 gear inch range.
If I were to run 1x, I would need a 42t ring with an 11-46 cassette to get close to the same range as that would be a 106.18 - 25.29 gear inch range.

Below are by current 1170 cassette and a wide range cassette. Between the 2nd and 8th cog, there is a 13 tooth difference on my setup compared to a 19 tooth difference on the 1x setup. Linear progression and tighter jumps for the 2x.
my current cassette- 11,12,13,15,17,19,22,25,28,32,36
an available wide range cassette- 11,13,15,18,21,24,28,32,36,40,46




ETA- When my current cassette finally dies, I will most likely buy an 11-34. The cassette range will be even tighter for sequential shifting.